A Detailed guide on Runtime Application Self Protection (RASP) Security

Enterprise software delivery has accelerated. Many teams now ship changes continuously, and APIs have become the front door for revenue, partner integration, and customer experience. DORA’s research frames this shift through deployment frequency and lead time, and elite teams increasingly deploy on demand.  The upside is faster product iteration. The downside is a faster moving attack surface, with less time between exposure creation and exploitation.

Attackers are matching that pace. 311 billion web applications and API attacks in 2024 were reported, a 33% year over year increase, a clear signal that perimeter only defenses are being outscaled.

Breach data points to the same business reality: initial access is often valid, and escalation is fast. Verizon’s 2025 DBIR reports that in the Basic Web Application Attacks pattern, about 88% of breaches involved stolen credentials, meaning many incidents begin with legitimate access. Mandiant’s M Trends 2025 adds that when an initial infection vector was identified, 33% of intrusions began with exploitation of a vulnerability, showing that known weaknesses still translate into real impact.

For CEOs and CISOs, the business pain is predictable:

1. Release velocity compresses the response window. Even strong teams need time to validate fixes and ship safely, while attackers move immediately.
2. API growth creates blind spots. Without reliable inventory and ownership, exposure accumulates through forgotten endpoints, inconsistent controls, and unmanaged versions.
3. Noise delays action. Too many signals without proof of exploitability slow engineering and dilute security focus.
4. Cyber incidents become business events. Downtime, fraud, regulatory scrutiny, and trust erosion are the costs that matter.
   

That is why runtime application self protection is gaining momentum. RASP security focuses on stopping exploitation inside the running application, where there is enough context to make high confidence decisions, and where you can blunt the impact while engineering fixes are still in flight.

What is Runtime Application Self Protection?

Runtime Application Self Protection, often shortened to RASP, is a security capability that runs inside a live application and uses runtime context to detect and stop attacks in real time. Instead of only inspecting traffic before it reaches your code, RASP security monitors what the application is actually doing during execution, how user input flows through the app and whether that behavior is attempting something unsafe such as executing malicious queries or commands.

Runtime application self protection (RASP) helps your application protect itself from the inside, while it is running, so exploitation attempts can be blocked even when fixes are still in progress.

How does RASP Security work?

RASP works by running inside the application runtime and watching what the app is actually doing, not just what the request looks like on the network. It instruments the application so it can observe execution, understand context and enforce policy at the moment risky behavior occurs.

The RASP Architecture includes the following layers: 

1. In app runtime agent (instrumentation layer)

• Deployed with the application (per service, per pod, per host, or as a library/agent depending on language)
• Hooks into the runtime to observe key operations like database queries, OS command execution, file access, deserialization and template rendering
• Tracks request context such as user identity, session, API route, parameters and code path
  

2. Context and detection engine (decision layer)

• Correlates inputs with execution behavior
• Detects exploit patterns based on where data flows and what the app is about to do, not just signatures
• Applies policies such as allow rules, block rules, virtual patches and anomaly thresholds
  

3. Response and enforcement (control layer)
Depending on configuration, RASP can:

• Block the specific request or API call
• Terminate a session or token flow
• Sanitize or neutralize dangerous inputs before they hit sensitive sinks
• Rate limit abusive behavior
• Generate high fidelity alerts with evidence (service, endpoint, stack trace, payload, affected function)
  

4. Telemetry and management plane (operations layer)

• Central console for policy management, tuning, rollout control and reporting
• Integrations into SIEM, SOAR, ticketing, CI pipelines and observability tools
• Dashboards that connect exploit attempts to affected services and priority fixes
  

How RASP plays out in real time

1. A request hits an API endpoint
2. The agent tracks how inputs propagate through code
3. When data reaches a sensitive sink, the engine evaluates exploitability
4. If malicious, RASP enforces a response immediately and logs evidence for triage and remediation

Why is RASP important

RASP is important because it reduces risk during the most dangerous period in modern software delivery: the gap between when a vulnerability exists in production and when it is fully fixed everywhere. 

From a business perspective, that gap is unavoidable. Engineering teams need time to validate fixes, coordinate releases, avoid regressions and work across dependencies. Meanwhile, attackers exploit known weakness patterns quickly, especially in internet facing applications and APIs.

Traditional controls often detect suspicious traffic but cannot confirm whether the application is actually being exploited, which leads to noise, slow decision making and missed high impact events.

This is where runtime application self protection earns its place. By operating inside the application, RASP security can detect when real exploitation is happening, stop it in the moment and produce evidence that helps teams prioritize the fixes that matter most. It turns security from a backlog problem into a real time risk reduction capability.

RASP in DevSecOps

DevSecOps is about shipping faster without increasing exposure. RASP supports that goal by creating a feedback loop between production reality and engineering action.

In a mature DevSecOps workflow, RASP is used in three practical ways:

1. Protect production while remediation is in flight. RASP provides RASP protection for high value services and APIs even when patching is still underway, reducing the chance that a known issue becomes an incident.
2. Improve prioritization and reduce waste. RASP telemetry shows which services and endpoints are actually targeted and which code paths are involved. That evidence helps AppSec and engineering focus remediation on exploitable issues instead of chasing theoretical findings.
3. Using RASP Insights to Strengthen Security Testing. Make security testing more meaningful by using RASP runtime insights. Observations from RASP can be translated into targeted test cases and guardrails for CI and staging environments, helping teams validate that fixes and protections hold up against realistic attack patterns rather than relying only on static scans.

The result is a security program that moves at delivery speed, with fewer emergency firefights and clearer accountability.

Characteristics of RASP

Strong RASP security implementations typically share these characteristics:

1. Runtime context awareness. Understands code execution, call stacks and how input flows through the application to sensitive operations.
2. In process detection and prevention. Can detect attacks at the moment of execution and take action, not just generate an alert after the fact.
3. High fidelity evidence. Captures actionable details such as service name, endpoint, payload, code path and affected function, which makes triage and remediation faster.
4. Tunable policies and safe rollout. Supports monitor mode first, targeted enforcement and policy tuning by application criticality to reduce false positives.
5. Broad integration into security operations. Feeds events into SIEM, SOAR, ticketing and observability tools so RASP becomes part of incident response and continuous improvement, not a separate console.‍
6. Practical support for modern architectures. Works across distributed services where feasible and helps protect the highest risk parts of the portfolio first, especially internet facing apps and APIs.

IAST vs RASP

IAST and runtime application self protection solve different problems at different points in the lifecycle, even though both benefit from being inside the application.

IAST (Interactive Application Security Testing) instruments an application during testing so you can identify vulnerabilities with high accuracy using real execution and data flow. It helps teams find and fix issues before release and it fits naturally into your broader testing program. 

RASP (Runtime Application Self Protection) instruments a live application at runtime so it can detect and respond to attacks while the app is running. In other words, RASP security is designed to prevent exploitation in production, using runtime context to make high confidence decisions when traffic reaches sensitive operations.

Read More: What Is API Security Testing.

How to choose between RASP or IAST from an executive perspective

If you are deciding where to invest, anchor on what outcome you are trying to drive: fewer vulnerabilities reaching production, or less business impact when something inevitably slips through.

• Choose IAST when your priority is prevention. IAST is the better fit when you want to reduce how often vulnerabilities ship by finding issues during development and test cycles, while fixes are still low cost and teams can remediate quickly.
• Choose RASP when your priority is impact reduction in production. RASP is designed to act inside the running service, helping reduce the chance that a production vulnerability turns into a breach, especially for internet facing applications and APIs where exploitation windows can be short and consequences immediate.
• Use both when you want full lifecycle coverage. IAST reduces exposure creation by helping teams ship safer code. RASP reduces exposure impact by adding runtime guardrails in production. Together, they cover both sides of the risk equation: likelihood and blast radius.

If you still operate legacy SOAP services, keep the testing story explicit.

RASP vs WAF

A WAF and RASP both reduce risk, but they operate in different places and answer different questions.

A WAF (Web Application Firewall) sits in front of applications and APIs. It inspects incoming traffic and blocks known bad patterns before requests reach your services.

RASP runs inside the application runtime. It can make decisions based on execution context such as the code path being executed and where data is flowing, then enforce protection immediately. This is why runtime application self protection is often more precise for confirming and stopping exploitation, especially when traffic looks normal at the HTTP layer.

Where each one is strongest

1. WAF is strongest for centralized, broad coverage and fast baseline protection at the edge.
2. RASP protection is strongest for high confidence detection and blocking inside the services that matter most, because it can see what the application is actually about to do.

Positioning WAF and RASP

You do not need a single control to solve every API risk. You need a layered system that reduces noise, limits blast radius, and gives your team leverage.

Start at the edge. A WAF helps filter commodity probes, bot driven noise, and known attack patterns before they consume app resources or overwhelm your team. Then assume some threats will still get through, especially targeted abuse and exploit attempts hidden inside otherwise valid traffic. That is where RASP earns its place: as a last line of defense inside the runtime, stopping attacks at the moment they would execute and cause real damage.

Finally, make it operable. Runtime defenses only work at scale when they are tied to visibility and governance. Visibility tells you what is actually happening across services and endpoints so you can tune controls and prove impact. Governance ensures ownership, standards, and policy consistency so protections do not drift team by team.

Types of Vulnerabilities detected by RASP

RASP is most effective against vulnerabilities where untrusted input reaches a dangerous operation inside the running application. Because it operates in process, it can detect exploit attempts at the moment they execute and apply RASP protection in real time, even when the inbound request looks normal at the edge.

Code vulnerabilities RASP commonly detects and blocks at runtime

Below are the code vulnerabilities that RASP detects:

1. Injection vulnerabilities
Injection vulnerabilities arise when untrusted input reaches interpreters or execution engines inside a running application. This includes database queries, operating system commands, and directory lookups. When input is not safely handled, attackers can manipulate queries or commands at runtime, leading to unauthorized data access, system level execution, or directory enumeration. Because these attacks only become dangerous at execution time, they are well suited to runtime detection and blocking.

2. Execution and interpreter abuse
Execution and interpreter abuse occurs when structured input influences how code is executed rather than what data is processed. Insecure deserialization, object injection, and server side template injection fall into this category. The application may appear to behave normally until input triggers unexpected code paths or dangerous method invocation. These issues are difficult to detect at the perimeter because the payloads often look valid until execution context is applied.

3. Web and file system exploitation
Web and file system exploitation targets how applications render output and interact with local resources. When untrusted input reaches browser facing rendering sinks, cross site scripting can occur. When input influences file paths or file operations, attackers may access unintended files or execute malicious uploads. These vulnerabilities become exploitable only when data flows into sensitive runtime operations, not when the request is first received.

4. Outbound request abuse
Outbound request abuse happens when applications make network calls based on user controlled input. This can lead to server side request forgery, where internal services or metadata endpoints are accessed unintentionally. These attacks often bypass edge controls because the initial request appears legitimate, and the risk only becomes visible when the application initiates the outbound call during execution, assuming the runtime has outbound visibility.

API specific vulnerabilities and attack scenarios RASP can detect

In API driven systems, RASP is most effective when untrusted input reaches dangerous runtime operations, allowing it to detect and stop certain exploit driven attack scenarios as they execute inside the application.

1. Injection and exploit prevention
RASP can stop exploit attempts driven through APIs by blocking malicious execution at the sink. This includes API delivered SQL injection, command injection, template injection and deserialization driven exploitation. This matters because API traffic is structured and automated, so payloads often bypass simple pattern matching, but they still become obvious at execution time.

2. Zero day and unknown vulnerabilities
RASP can provide meaningful protection against zero day and unknown vulnerabilities by focusing on malicious runtime behavior rather than relying only on known signatures. Even when the exact CVE is new, many exploit chains still require the application to perform a high risk action and RASP can intercept that action while a permanent fix is still in progress.

3. Protection against authenticated attackersRASP can still detect and block exploitation even after an attacker is authenticated, because enforcement happens inside the runtime, not only at the perimeter. This is critical for APIs where attackers frequently use stolen credentials or tokens to reach sensitive endpoints and then attempt injection or exploitation through legitimate looking calls.

Top RASP Security Tools

Below are widely used RASP security tools and adjacent platforms that deliver runtime application self protection capabilities. 

1. Contrast Security

Contrast Security positions itself as in app and API protection using embedded runtime sensors that provide real time visibility and defense. It is often described as combining application detection and response concepts with classic RASP style protection, with a strong focus on developer context.

Best for: Teams that want runtime protection paired with rich execution context to reduce false positives and prioritize exploitable issues.

Key features

• Embedded runtime sensors for application and API visibility
• Runtime blocking and rapid response protections, including virtual patching style controls
• Vulnerability detection tied directly to runtime execution paths

Pros

• Strong accuracy signals for vulnerability detection and exploit confirmation
• Detailed runtime context helps developers understand root cause and impact

Cons

• Noise and tuning pain (false positives and false negatives)
  Reviewers mentioned needing to deal with false positives and occasional false negatives, which can slow triage and reduce developer trust if it is not tuned well.
• Reporting and analytics gaps
  Users call out reporting as inadequate for their needs, sometimes requiring extra attention to get the right views for leadership reporting and program metrics.
• Coverage limitations (language and framework support, especially outside core back end stacks)
  Feedback notes limited language and framework support in some areas, plus gaps for certain codebases like front end UI coverage.

Pricing: Free trial available. Pricing is typically quote based and not publicly listed.

G2 rating: 4.5 / 5 

2. Waratek

Waratek is positioned around runtime protection with a strong emphasis on virtual patching outcomes, aiming to reduce exposure without requiring application code changes.

Best for: Organizations that need fast risk reduction in environments where patching and upgrading are slow or operationally risky.

Key features

• Runtime vulnerability shielding without code modification
• Portfolio wide protection against known and zero day vulnerabilities
• Emphasis on reducing attacker dwell time during patch gaps

Pros

• Effective compensating control for legacy and hard to patch systems
• Simple operational model with minimal developer involvement

Cons

• Limited public detail on depth of detection compared to larger platforms
• Smaller ecosystem and fewer integrations than broader security suites
• Fit must be validated carefully for language and framework support
  
  

Pricing: Secure and Elevate editions listed with free trials. Final pricing is typically handled via sales.

G2 rating: 4.7/ 5

3. Imperva Runtime Application Self Protection (RASP)

Imperva’s RASP is framed as classic runtime protection embedded directly into the application, focused on monitoring execution and blocking attacks in real time.

Best for: Security teams seeking traditional RASP capabilities aligned to OWASP style exploit blocking.

Key features

• In app monitoring and real time blocking
• Protection claims against OWASP Top 10 classes like SQLi and XSS
• Context aware detection designed to reduce alert noise

Pros

• Straightforward RASP model that aligns well with traditional AppSec programs
• Effective at stopping known exploit patterns at execution time

Cons 

• Smaller number of reviews makes it harder to assess large scale deployments
• Interface and workflows may require onboarding time
• Less emphasis on developer centric context compared to newer platforms

Pricing: Typically quote based.

G2 rating: 5/ 5

4. Dynatrace

Dynatrace is primarily an observability platform but is frequently evaluated as a RASP option when teams want runtime security and deep production visibility in one place.

Best for: Large enterprises that want runtime telemetry, dependency mapping, and security context tightly integrated into operations.

Key features

• Full stack monitoring with automated service discovery
• Runtime execution visibility tied to services and APIs
• Broad integrations with security and operations tooling

Pros

• Very mature platform with strong enterprise adoption
• Deep runtime visibility beyond pure security use cases

Cons 

• Pricing and licensing can be complex at scale
• Rollout requires clear ownership and platform discipline
• Security controls are not as purpose built as dedicated RASP tools

Pricing: Starts at $69 per month billed annually per 8 GB host, with module based packaging.

G2 rating: 4.5/5

5. Appdome

Appdome focuses on mobile application protection and is commonly evaluated for RASP style runtime defenses in mobile environments.

Best for: Mobile first organizations that want runtime protection without heavy engineering effort.

Key features

• No code mobile security platform
• Broad runtime protection coverage for mobile threats
• Fast implementation and deployment workflows

Pros

• Very easy to adopt with minimal developer effort
• Strong customer support and onboarding experience

Cons

• Pricing can become expensive as mobile portfolios grow
• Platform abstraction limits deep customization
• Focused primarily on mobile use cases, not backend APIs

Pricing: Annual subscription model, typically quote based.

G2 rating: 4.8/ 5

6. DoveRunner

DoveRunner is positioned around mobile app shielding with runtime application self protection features aimed at preventing tampering and runtime manipulation.

Best for: Mobile teams looking for a packaged set of runtime protections with a low barrier to entry.

Key features

• Runtime application self protection for mobile apps
• Anti tampering, anti reverse engineering, jailbreak and rooting detection
• Real time analytics and monitoring dashboard

Pros

• Broad feature coverage for mobile runtime threats
• Free tier enables low risk evaluation

Cons

• Requires disciplined rollout across app versions and releases
• Less suited for backend or API runtime protection
• Analytics depth may be limited for large scale programs
  
  

Pricing: Free tier available. Paid plans start at $129 per app per month.

G2 rating: 4.7/ 5

7. Jscrambler

Jscrambler is best known for client side protection and JavaScript integrity controls and is also reviewed in the RASP category for browser side runtime defense.

Best for: Organizations focused on client side risk reduction and third party script control.

Key features

• Webpage integrity and third party script monitoring
• Real time client side threat detection=
• Code integrity protections including obfuscation and self defending JavaScript

Pros

• Strong client side security focus that complements backend controls
• Good automation and deployment capabilities

Cons

• Initial setup and learning curve can be steep
• Dashboard usability concerns mentioned in reviews
• Limited relevance for API or server side runtime protection
  
  

Pricing: Two editions available. Pricing is typically handled through vendor plans and quotes.

G2 rating: 4.4/5

Why RASP is a good to have for API Security

Runtime application self protection can be a meaningful part of an API security program when it is scoped and positioned correctly, but it is not a complete API security control plane. Think of it as a last line of defense inside the service: it detects and can block certain exploit behaviors at the point of code execution. 

Deployed behind strong gateway controls, authentication, authorization, and rate limiting, RASP reduces the chance that a technical vulnerability is successfully weaponized into data loss, fraud, or an outage. It complements API security, it does not replace it.

Where RASP is effective for APIs

RASP runs inside the application runtime, so it can see what the code is doing, not just what the request looks like.

1. Injection and exploit prevention

RASP is strongest when API inputs reach dangerous sinks. It can help detect and block:

• SQL injection and NoSQL injection
• OS command injection
• Expression language injection
• Deserialization attacks
• SSRF triggered from API inputs
• Path traversal

Injection and exploit prevention  matters for APIs because they are designed to accept structured input such as JSON and XML and to directly invoke backend logic and data access layers. API requests often interact with high value systems, including databases, internal services, and file systems, which means a single malicious request can trigger significant impact if it reaches a dangerous operation.

RASP helps reduce this risk by tracking how untrusted input flows through the application code path and by observing execution in real time. When data reaches a sensitive sink, such as a database query or system call, RASP can detect unsafe behavior and block the request before damage occurs.

This value is independent of whether the API is built using REST, GraphQL, or gRPC. If untrusted input reaches a dangerous operation inside the runtime, RASP protection can intervene at the moment execution occurswould occur.

2.  Zero day and unknown vulnerabilities

Zero day and unknown vulnerabilities are difficult to defend against because they often do not match known signatures or predefined rules. RASP addresses this by focusing on exploit behavior and unsafe runtime actions rather than relying only on signature based detection. This includes patterns such as unsafe reflection or eval style execution, unexpected code paths that signal exploitation, and abuse of insecure framework internals that only become visible during execution.

This approach is especially valuable for custom APIs where generic signatures are unreliable, legacy services where patch velocity is slow, and rapidly changing microservices where new exposure paths appear continuously. By operating inside the runtime, RASP provides a practical way to reduce risk during the patch gap while fixes are still being validated and deployed.

3. Protection against authenticated attackers

Many high impact API attacks occur after authentication, using stolen credentials, valid tokens, or compromised partner access. Once TLS is established and authentication appears legitimate, perimeter controls often lose the context needed to determine whether the request should be allowed.

RASP can still provide protection because it operates inside the application and has access to runtime context. This includes user identity within the application, the authorization context available to the code, and the actual business logic flow as execution occurs. Because enforcement happens at the point where privileged actions are executed, RASP security tools remain effective even when an attacker is already authenticated and interacting with APIs using seemingly valid access.

Where RASP is not effective for APIs

This is where expectations must be set. RASP is designed for exploit prevention, not for API design flaws, authorization gaps, or abuse patterns.

1. API specific threats and OWASP API Top 10 risks. RASP is weak or blind to many of the most common API breach drivers, including broken object level authorization, excessive data exposure, mass assignment, broken authentication, unrestricted resource consumption, schema abuse, and GraphQL query complexity attacks. These issues are rooted in design and authorization logic rather than technical exploitation. In many cases the code executes exactly as written, but it enforces the wrong business rule. RASP observes valid execution and cannot reliably determine whether the underlying decision was correct.

2. Protocol level and posture problems. RASP does not replace API layer controls such as discovery and inventory, schema validation, version governance, contract enforcement, or identity flow hardening. Problems like deprecated endpoint exposure, parameter tampering against API contracts, and JWT or OAuth misconfiguration must be addressed at the gateway or API security platform level, not inside the application runtime.

3. Traffic management and volumetric abuse. RASP is not suitable for traffic wide threats such as DDoS attacks, brute force attempts, bot driven abuse, or rate based enumeration. Because it operates after a request has already entered the application, it cannot protect shared edge capacity or enforce broad traffic controls at scale.

APIs vs web apps: key distinctions that change the threat model

RASP was originally built around web application exploit patterns, where attacks are often payload based and sink based blocking is highly effective. APIs shift the threat model toward authorization and logic abuse, where payloads can be valid and intent is the real issue. 

That is why RASP delivers strong value for exploit mitigation, but limited value for many API breach patterns.

One key outcome: APIs shift the threat model toward authorization and logic abuse, where RASP provides limited value because it cannot reliably determine whether a request should be allowed based on business intent and object ownership.

Ideal architecture for API security

RASP should act as a supporting layer, not the core of API security. A practical and effective architecture typically includes:

• Client: External consumers, applications, and services initiating API requests.
• API gateway and API Security Platform: Responsible for authentication, authorization, schema validation, rate limiting, and controls for risks such as BOLA.
• WAF (Optional): Provides edge level filtering for volumetric attacks and basic threat patterns.
• Application Runtime with RASP: Delivers in process exploit prevention and protects against low level runtime attacks.

This layered model prevents a false sense of safety and makes RASP security testing more honest and defensible.

When RASP makes sense for APIs

RASP makes sense for APIs when you own the API code and can safely deploy runtime instrumentation, especially for services that interact heavily with databases, operating system resources, or internal services. It is a good fit when protection is needed against injection, deserialization, and SSRF style exploits, particularly in legacy systems where fixes cannot be rolled out quickly. In these cases, RASP provides compensating control and runtime evidence that helps teams prioritize remediation and improve incident response, rather than relying on alerts alone.

Where RASP is a poor fit

RASP is a poor fit when the primary risks are authorization failures such as BOLA or IDOR, when large public APIs require continuous discovery and posture management, or when architectures rely heavily on GraphQL or event driven patterns where abuse is driven by logic and behavior rather than exploits. It is also not sufficient when strong contract enforcement, schema validation, or OAuth and JWT correctness guarantees are required. RASP can still add value as an exploit mitigation layer, particularly for classic injection and runtime exploit behavior during zero day windows, and it can help even against authenticated attackers by enforcing controls inside the runtime. However, it does not address the core drivers of modern API breaches, which are authorization gaps and business logic abuse. The correct positioning is to use RASP as defense in depth behind purpose built API controls and to rely on security testing to clearly define what RASP covers and where it cannot provide protection.

Benefits of RASP Protection

RASP protection delivers the most value when you measure it in business outcomes, not feature checklists. It reduces the likelihood that a technical vulnerability becomes downtime, fraud, or a reportable incident during the window when fixes are still in flight.

1. Stops exploitation in real time. RASP runs inside the application runtime and can block attacks at execution time, not just detect suspicious traffic. This is especially useful for injection driven attacks, deserialization abuse, SSRF and similar exploit paths where damage happens only when the code executes.

2. Shrinks the patch gap risk window. Most organizations cannot patch instantly across every service, dependency and environment. RASP provides a compensating control that helps protect production while engineering validates and deploys the permanent fix, including during high pressure vulnerability waves.

3. Improves accuracy and reduces alert noise. Because RASP security tools see runtime context, they can often confirm whether an input actually reaches a dangerous sink. That produces higher fidelity alerts and fewer false positives compared with controls that only inspect traffic at the edge.

4. Protects against authenticated attacker scenarios. Many high impact incidents start with valid credentials or tokens. RASP can still stop exploit attempts after authentication because enforcement happens inside the runtime where privileged actions occur.

5. Accelerates triage and remediation. RASP telemetry typically includes evidence like the affected service, endpoint, code path and execution context. That makes incidents easier to investigate and helps teams prioritize fixes based on real exploitability, not just CVSS.

6. Enables safer modernization and legacy risk reduction. For older applications and APIs where refactoring and patching are slow, RASP protection can reduce exposure without requiring immediate code changes everywhere. This is valuable during cloud migration, microservices decomposition and platform modernization.

7. Strengthens compliance posture and reporting. When implemented well, RASP produces defensible evidence of exploit attempts and the controls that prevented impact. This can support audit narratives, risk reviews and executive reporting tied to measurable reduction in exploitable exposure.

Challenges with RASP Protection and Solutions

RASP and several legacy application controls were born in an era of code heavy, browser driven web applications. That world had a predictable shape: a UI, sessions, form submits, and a smaller number of high value routes. RASP fit because it could sit inside a single runtime, observe execution, and stop common exploit classes like injection and unsafe function calls as they occurred.

API first systems flipped that model. Your primary interface is now machine to machine traffic across hundreds of endpoints, spread across microservices, languages, clouds, and teams. The dominant threats are no longer just exploit payloads. They are authorization mistakes, object access abuse, workflow automation, and resource exhaustion.

Why RASP is fundamentally misaligned with API threats

1. It reacts after the request enters the application, which is often too late

RASP works inside the running application, meaning the request has already traversed your edge, your gateway, and typically your service framework before RASP can observe meaningful execution signals.

That timing matters in APIs for two reasons:

• Cost is incurred early. Authentication, deserialization, schema parsing, and database lookups can happen before RASP has enough context to block safely. With modern APIs, attackers exploit expensive endpoints to create disproportionate backend load.
  
  
• Upstream infrastructure still gets flooded. Protocol and application layer volumetric attacks can saturate connections and worker pools before your business logic is even in play. The HTTP/2 Rapid Reset wave is a concrete example of protocol behavior being abused at a massive scale.

2. RASP is strongest on exploit payloads, weakest on authorization intent

The most exploited API failures are about who can access which object, not whether the payload contains suspicious strings. OWASP highlights object level authorization as a top risk precisely because attackers can simply manipulate IDs and access other users’ data.

RASP does not inherently know whether user A should access invoice 91827. That decision lives in your authorization model, your data relationships, and your business rules, often spanning multiple services.

3. The API attack surface is distributed, RASP is inherently per runtime

In microservices, protection that requires consistent runtime instrumentation across every language, framework, and deployment unit becomes brittle fast. Coverage gaps are inevitable, and attackers only need the weakest service.

4. APIs demand pre request controls and positive models

Modern API defense relies on knowing what good looks like: schemas, token requirements, allowed methods, and expected workflows. RASP is not a contract enforcement layer. It is a runtime detection layer. Those are different jobs.

Where RASP is not effective for APIs: mapping to OWASP API Top 10

RASP may help with a narrow slice of API risk, mostly around certain injection patterns. But across the OWASP API Security Top 10, the primary problems are authorization, workflow abuse, inventory, and unsafe integrations, where RASP is a poor fit.

Two API risk areas RASP routinely misses

1. Protocol level attacks. APIs increasingly run on protocols and patterns that can be abused before application logic: HTTP/2 multiplexing behaviors, connection handling, and request cancellation patterns. RASP cannot meaningfully defend shared protocol infrastructure because it operates inside the application process, after the protocol stack and request routing have already done their work.

2. Traffic management and volumetric abuse. Many API outages are not classic exploits. They are legitimate looking calls executed at abusive rates, against expensive endpoints, or across sensitive flows. OWASP explicitly calls out resource consumption and the ease of executing concurrent requests. RASP is not a traffic governor. It cannot enforce quotas, shape traffic, or protect upstream saturation at scale.

Practical solutions to mitigate API Threats that RASP

If your goal is real API protection, treat RASP as optional defense in depth, not the foundation. Build a layered approach that stops threats before they hit application logic and validates authorization intent throughout the request lifecycle.

1. Enforce identity and authorization at the edge, and in the service. Validate tokens, scopes, and role requirements at the gateway, but still enforce object and function authorization in the service to prevent bypass and lateral movement.

2. Adopt schema and contract enforcement. Use OpenAPI schemas and positive security models to reject unexpected fields and malformed payloads. This is one of the fastest ways to reduce mass assignment style abuse and data overexposure.

3. Implement identity based rate limiting and workflow protection
Move from IP throttling to per token and per user controls, especially on expensive endpoints and sensitive flows like login, checkout, password reset, and signup.

4. Harden protocol and layer 7 availability controls. Pair API gateways and WAAP style protections with modern DDoS mitigation tuned for HTTP/2 and API traffic patterns.

5. Continuously discover APIs and govern the full inventory. You cannot secure what you cannot see. Build continuous discovery, ownership, version tracking, and deprecation enforcement to address improper inventory management.

6. Shift left with API security testing that targets authorization and logic
Test for object level and function level authorization failures, sensitive business flow abuse, and unsafe third party consumption, not just injection signatures.

Where RASP still fits: if you already have it, keep it for what it does well inside specific runtimes, mainly helping reduce exploitation of certain code level vulnerabilities. Just do not confuse that with API security coverage.

Best Practices to follow for RASP

RASP is a production control. It reduces exploit risk at runtime, but it does not replace core API controls. The best results come when you treat runtime application self protection as one layer in a broader API security stack, not the foundation.

1. Position RASP correctly in your security architecture. Use RASP for exploit prevention inside the application runtime. Do not treat it as a complete API security solution. It is strongest against injection and runtime exploit chains and weaker against API logic and authorization abuse.

2. Put an API gateway in front of RASP protected services. Production controls like RASP do not cancel out the need for an API gateway. The gateway should handle authentication, authorization enforcement patterns, schema validation, versioning controls and rate limiting. RASP should sit behind it to stop technical exploitation that reaches code execution.

3. Keep API penetration testing in the program. Production controls like RASP do not cancel out the need for API penetration testing. Pen testing is how you validate real world exploitability and confirm you can detect and respond to issues that RASP will never catch well, such as broken object level authorization, broken function level authorization, excessive data exposure and workflow abuse.

4. Add API specific tooling that can prevent and block API specific threats. RASP cannot reliably prevent API first risks like BOLA or IDOR, mass assignment, schema abuse and resource consumption attacks. Use an API security platform or API specific controls that can discover APIs, enforce contracts, detect abuse patterns and block API logic attacks. This is the layer that closes the gap RASP cannot cover.

5. Start in monitor mode, then graduate to targeted blocking
Deploy RASP in observe mode first to establish a baseline and avoid breaking business critical flows. Then enable blocking on the highest risk services and endpoints, especially those that touch databases, internal services and sensitive operations.

6. Scope coverage intentionally and prove it with testing
Define which services, routes and environments are protected. Validate coverage with RASP security testing and re-validatere validate after major releases, dependency upgrades and infrastructure changes.

7. Tune policies by application criticality, not one size fits all
High volume public APIs may need different thresholds than internal APIs. Use tiers for enforcement so you reduce noise without reducing protection.

8. Integrate RASP signals into operations and remediation
Send RASP events into your SIEM and incident workflows. Use runtime evidence to prioritize fixes based on exploitability and business impact, not just vulnerability severity.

9. Define ownership and rollout discipline
Treat RASP as a platform capability. Standardize agent deployment, versioning, rollback procedure and performance guardrails so engineering teams can adopt it without friction.

10. Measure outcomes that leadership cares aboutTrack blocked exploit attempts, time to triage, time to remediate high risk issues, production incident reduction and coverage across critical APIs. If RASP is not improving these outcomes, adjust placement, tuning, or the surrounding API controls.

Achieve Complete API Security with Runtime Application Self Protection using Levo

Runtime application self protection is powerful for stopping exploit behavior inside the application, but it was not built to solve the biggest API problems: authorization failures like BOLA and BFLA, excessive data exposure, schema drift, inventory gaps and abuse patterns. Those are API specific threats that require API native visibility, governance, testing and enforcement.

That is exactly where Levo fits. Levo is an API security platform custom built for API first architectures and it prevents most of the API attacks that RASP cannot defend against by covering the full lifecycle: proactive discovery and testing, governance and threat detection and runtime detection and blocking.

1. Proactive: Visibility plus Security Testing

This layer ensures you actually know what exists, what it does and what data it touches, then continuously validates security before issues become incidents.

• API Inventory: continuously discovers internal, external, partner, third party, shadow and zombie APIs so nothing critical stays unmanaged.
• API Documentation: auto generates accurate documentation from live traffic so teams stop guessing what endpoints do.
• Sensitive Data Discovery: identifies and maps PII, PHI, PCI and token flows across APIs so you can find exposure paths and enforce policies.
• API Security Testing: continuous API security testing in CI and runtime to validate auth, data handling, misconfigurations and exploitability across your real endpoints.

2. Governance: Monitoring.

This layer ensures drift, misconfigurations and API specific vulnerabilities are detected continuously, across environments, without relying on periodic audits.

• API Monitoring: posture monitoring and governance that detects schema and auth drift, token misuse and high impact issues continuously.
• Vulnerabilities Reporting: exploit validated API vulnerability management, including API layer issues like AuthZ failures such as BOLA and BFLA, data exposure, injection flaws and more.

3. Runtime: Detection and Blocking

This layer is where prevention becomes real. Instead of only alerting, you can stop confirmed attacks in production.

• API Protection: runtime detection and blocking for APIs across environments, designed to enforce protection with low overhead and without sacrificing control or privacy.

• API Detection: runtime detection that surfaces unmanaged risk and provides high fidelity, context rich detections across real traffic, including encrypted flows inside the runtime.

Together, these modules ensure enterprises are not just discovering and reporting API issues, but continuously detecting, remediating and blocking them across the full API lifecycle: visibility to eliminate blind spots, testing to validate security controls, governance to catch drift and logic issues and runtime protection to stop active attacks.

Implementing API Security beyond RASP with Levo

RASP is effective for APIs as an exploit mitigation control, not as an API security solution. It is strong at technical exploit prevention when an API input triggers a dangerous runtime action. It is weak at API logic and authorization abuse, where requests are valid but business rules are wrong. 

That is why RASP is best deployed behind an API gateway and should not be treated as API security on its own. RASP focuses on exploit prevention inside the application runtime, but it does not provide full visibility or coverage across the API lifecycle.

Levo protects APIs from build through runtime by combining early visibility and security testing with continuous monitoring, threat detection, and inline runtime blocking. Coverage for OWASP API Top 10 risks is achieved through a combination of proactive testing and runtime enforcement, rather than relying on a single blocking layer.

Levo coverage across OWASP API Top 10 from build to runtime 

• API1 Broken Object Level Authorization (BOLA). Levo helps you discover the endpoints and objects involved, test object level access paths, detect abnormal object access in production, and block abusive access patterns when enforcement is enabled. Modules: API Inventory, API Security Testing, API Detection, API Protection.
• API2 Broken Authentication. Levo helps validate authentication related weaknesses through testing and monitoring signals, and detect suspicious runtime behavior tied to tokens and identity context. 
• API3 Broken Object Property Level Authorization. Levo maps sensitive fields and data exposure paths and tests for improper property level access and overexposure.
• API4 Unrestricted Resource Consumption. Levo can surface and respond to abusive patterns through monitoring, detection, and runtime protection, complementing gateway rate limiting. Modules: API Monitoring, API Detection, API Protection.
• API5 Broken Function Level Authorization (BFLA). Levo supports testing and runtime detection for unauthorized function access and privilege boundary breaks. Modules: API Security Testing, API Detection, API Protection.
• API6 Unrestricted Access to Sensitive Business Flows. Levo supports testing and runtime detection for abuse of high value workflows and business logic abuse patterns. Modules: API Security Testing, API Detection, API Protection, plus Monitoring for ongoing visibility.
• API7 Server Side Request Forgery (SSRF). Levo can detect and help block SSRF style exploitation paths at runtime when API inputs drive outbound requests. Modules: API Security Testing, API Protection.
• API8 Security Misconfiguration. Levo governance and monitoring surfaces configuration drift and exposure signals so teams can remediate before exploitation and report vulnerabilities in real time. 
• API9 Improper Inventory Management. Levo continuously discovers and enriches your API inventory and can generate documentation from observed behavior, reducing shadow and zombie API risk with runtime API threat detection. 
• API10 Unsafe Consumption of APIs. Levo supports testing and runtime detection for unsafe third party API consumption and downstream exploit chains. Modules: API Security Testing, API Detection, API Protection.

In short, use runtime application self protection where it excels at preventing exploits inside the runtime. Use Levo to cover the full API lifecycle, enabling continuous discovery, testing, monitoring, detection, and blocking of the API specific risks that lead to real incidents.

See how Levo.ai strengthens RASP based security with full lifecycle API protection. Book your demo to understand how modern runtime security can scale with real world APIs.