> API Security Audit_
APIs carry the most valuable traffic your product has: customer records, payments, internal operations. They are also easy to call directly, without your app's interface and the limits it imposes.
An API security audit from Krasty Soft checks whether each endpoint protects that traffic on its own. We review the code, test every route with real requests and deliver a ranked list of fixes with exact locations and clear guidance.
> When Does Your Business Need an API Security Audit?_
An API needs its own review whenever more people or systems start to depend on it. Common triggers include:
- You are opening a public or partner API, or publishing an SDK.
- Your mobile app, web app and integrations all share one backend.
- You are moving from a monolith to microservices or adding a new gateway.
- A partner or enterprise client requires a security assessment before integration.
- You process payments, health data or personal data under PCI DSS, HIPAA or GDPR.
- You have added AI features that call model APIs or expose new endpoints.
Teams often ask us to audit API endpoints before they are announced, because changing a public contract later is slow and expensive.
> What Is Included in Our API Security Audit_
Our API audit combines code review with hands-on testing of the running service. We follow the OWASP API Security Top 10 and extend it with checks for your business logic. The scope usually covers five areas.
API Authentication and Authorization Testing
We check how clients prove who they are: API keys, sessions, OAuth flows and JWT tokens. We look at how each token is issued, signed, validated, refreshed and revoked, and whether it can be forged, replayed or used after logout.
Then we test authorization on every route. A valid token must not give access to someone else's data, and each scope must allow only what it promises.
API Endpoint and Access Control Assessment
We map every endpoint, including old versions, debug routes and internal services that are reachable from outside. For each one we test access control by object, by field and by function.
The most common finding is broken object-level authorization: change an ID in the URL and you get another customer's record. We test for it systematically, with accounts in different roles and tenants.
Data Protection and Input Validation
We check what each response returns. APIs often send whole database objects, including fields the interface never shows, such as internal notes, other users' emails or password hashes.
On input, we test validation, type handling and limits: injection, mass assignment of fields like "role" or "balance", oversized payloads and file uploads.
API Configuration and Infrastructure Security
We review rate limiting, CORS, TLS, error handling, logging and the gateway or proxy in front of the service. Misconfiguration here can expose stack traces or secrets and turn a small bug into a large incident.
We also check how services talk to each other inside your network. Internal APIs are often left without authentication on the assumption that only trusted services can reach them, and one exposed service breaks that assumption.
Third-Party API and Integration Security
Your API also consumes other APIs. We check how webhooks are verified, how outgoing requests are restricted and how keys for payment, email and cloud services are stored and rotated.
An AI API security audit adds checks for endpoints that call language models: prompt injection, leaks of system prompts and private data, and cost abuse through unlimited requests. For autonomous agents with tools, we recommend a dedicated AI agent security audit.
> Common API Security Risks and Vulnerabilities_
Most API breaches come from a short list of mistakes. These are the ones we test for in every engagement:
- Broken object-level authorization: users access records that belong to others.
- Broken authentication: weak tokens, missing expiry or flawed login and refresh flows.
- Excessive data exposure: responses include fields the client should never see.
- Missing rate limits: brute force, scraping and expensive requests are not blocked.
- Broken function-level authorization: regular users can call admin actions.
- Server-side request forgery: the API can be made to fetch internal resources.
- Forgotten endpoints: old versions and test routes that still run without protection.
> Our API Security Audit Process_
Each engagement follows the same clear steps, from scoping to verified fixes.
- Scoping
We agree on the services, versions and roles in scope and confirm the price and timeline.
- Discovery
We study your code, specification files and traffic to build a full map of endpoints.
- Testing
We test each endpoint with penetration techniques on staging and confirm every vulnerability by hand.
- Reporting
Findings are ranked by severity, with requests that reproduce them and recommended fixes.
- Debrief and retest
We review the report with your developers and verify the fixes once they ship.
> Benefits of a Professional API Audit_
A professional assessment protects both your data and your integrations:
Customer data stays private, even when attackers call the API directly.
Partners and clients get evidence that your platform is safe to integrate with.
Hidden and outdated endpoints are found and removed.
Abuse and runaway costs are prevented with proper limits.
Your developers get specific, reproducible fixes instead of generic advice.
> Industries & Use Cases_
We audit APIs for fintech platforms, healthcare systems, SaaS products and ecommerce backends. Typical cases include public developer APIs, mobile backends, partner integrations, payment and payout services, and internal APIs exposed through a gateway.
In multi-tenant SaaS products, the key question is whether one tenant can ever reach another tenant's data. We test it with separate accounts in each role.
An API audit can be ordered on its own or as part of a broader application security audit that covers your web and mobile apps as well.
> FAQ About API Security Audit_
Here are short answers to the questions we hear most often about API audits.
Does an API Audit Include Third-Party Integrations?
Yes. We review how your API calls and receives data from third parties, including webhooks, payment providers and cloud services. We do not test the providers' own systems.
Does an API Security Audit Cover REST, GraphQL, and SOAP APIs?
Yes. We test all three. GraphQL gets extra checks for introspection, query depth, batching and field-level access, and SOAP gets checks for XML parsing issues.
Can an API Security Audit Identify Business Logic Vulnerabilities?
Yes, and this is where manual testing matters most. Scanners cannot tell that a refund should not exceed a payment or that a step should not be skipped. We learn how your application should behave and test where it does not.
How Often Should APIs Undergo Security Audits?
We recommend an audit before any public release, after major changes to authentication or data models, and at least once a year. APIs that handle payments or sensitive data benefit from more frequent reviews.