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    API Penetration Testing

    APIs power mobile apps, partner integrations, and microservices, and they are a prime target for abuse. Budget Security delivers manual API pentesting focused on authentication, authorization, input handling, and business logic risks that scanners often miss.

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    We test how tokens are issued and validated, how object level authorization holds up under real requests, and how edge cases in parameters and workflows can be chained into impactful issues. Coverage is tailored to your API surface and documentation available (OpenAPI/Swagger, Postman collections, etc.).

    Book and scope online, see pricing upfront, and track validated findings as they are discovered. Then export compliance ready reporting and retest fixes from your dashboard.

    Methodology

    How we test APIs

    Testing blends structured manual techniques with automation helpers to explore endpoints, authentication flows, and data access patterns. We prioritize issues with realistic exploitability and business impact, not noisy theoretical findings.

    01

    Specification review

    OpenAPI or Postman collection ingestion, plus discovery of endpoints missing from the spec.

    02

    Authentication

    Token issuance, signature validation, expiry, refresh flows, algorithm confusion on JWTs.

    03

    Object-level authorization

    Systematic BOLA/IDOR testing across every resource identifier and every role.

    04

    Function-level authorization

    Admin-only operations reachable by standard users, undocumented verbs on known paths.

    05

    Mass assignment & injection

    Over-posting protected fields, query and command injection through parameters and headers.

    06

    Rate limiting & abuse

    Enumeration, credential stuffing surface, cost-amplification and resource exhaustion.

    Example finding

    This is the format a finding arrives in.

    An example of the format. Every finding carries a rating, reproduction steps and remediation guidance.

    CRITICALCVSS 9.4CWE-915

    Mass assignment on POST /v3/users

    The user-creation endpoint binds the whole request body to the model. Supplying "role":"admin" during self-registration grants full administrative access.

    Remediation

    Bind an explicit allow-list of fields and reject unknown properties at the schema layer.

    Deliverables

    What is included

    No upgrade tiers. The auditor-ready package is the standard package.

    Manual testing by OSCP certified penetration testers
    Deep focus on authn/authz, injection, and abuse scenarios
    Clear reports with reproduction steps and remediation guidance
    Compliance oriented documentation for SOC 2, ISO 27001, and NIS 2 programs
    Self serve booking and one click retesting after remediation
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    Other penetration testing services

    All

    All penetration testing services

    WEB

    Web Application Penetration Testing

    OWASP-aligned manual testing: auth flaws, injection, broken access control, business logic.

    NETWORK

    Network Penetration Testing

    Exposed services, misconfigurations, AD attack paths and segmentation testing.

    MOBILE

    Mobile Application Penetration Testing

    iOS and Android: data storage, transport security, platform-specific weaknesses.

    CLOUD

    Cloud Penetration Testing

    FAQ

    API Penetration Testing: FAQ

    What types of APIs can you test?
    We commonly test REST/JSON APIs and similar modern API styles. Share your API documentation and authentication model so testing matches how your product actually works.
    Can you test GraphQL or gRPC?
    Coverage depends on your stack and scope. During onboarding, we align on interfaces, auth mechanisms, and the best way to exercise your endpoints safely and thoroughly.
    Do you need API documentation?
    Documentation speeds up testing and improves coverage, but it is not always required. Grey box and white box approaches can significantly improve depth when specs and samples are available.
    How do you handle authentication in testing?
    We test token issuance, refresh flows, scopes/roles, and enforcement on protected endpoints. You provide test accounts and credentials according to your rules of engagement.
    What about rate limiting and abuse cases?
    Where in scope, we evaluate weaknesses that enable abuse, such as excessive data exposure, broken object level authorization, and flawed business rules, aligned to realistic attacker goals.
    How do I get a price estimate?
    Use our penetration test cost calculator. Pricing typically scales with endpoint count, authentication complexity, and testing approach.