What Is API Security?
API security is the practice of protecting application programming interfaces (APIs) from misuse, data exposure, and attack. It covers who can call each endpoint, what data they can see or change, how much they can request, and how the API handles bad input.
API security testing checks all of this the way an attacker would: by calling your endpoints directly, without your app's interface in the way.
This Is For You If...
Your mobile app, frontend, or partners talk to your API directly
You run a multi-tenant SaaS where one customer must never see another's data
You expose a public or partner API, webhooks, or a GraphQL endpoint
You've seen bots, scraping, or unexplained traffic spikes on your API
An enterprise customer wants API security test results before signing
The OWASP API Security Top 10 and What We Test
The OWASP API Security Top 10 (2023 edition, the current version) lists the most critical API risks. Every test we run covers all ten:
Risk | What It Means | What We Test |
API1 Broken Object Level Authorization | Changing an ID returns someone else's data | Every endpoint that takes an object ID, across users and tenants |
API2 Broken Authentication | Weak tokens or login flows | Token signing and expiry, refresh tokens, password reset, API keys |
API3 Broken Object Property Level Authorization | Responses expose, or requests accept, fields they shouldn't | Over-exposed fields and mass assignment, such as setting role=admin |
API4 Unrestricted Resource Consumption | No limits on requests or payload size | Rate limits, pagination, upload size, expensive queries |
API5 Broken Function Level Authorization | Regular users can call admin functions | Admin and internal endpoints, HTTP method switching |
API6 Unrestricted Access to Sensitive Business Flows | Flows can be automated and abused | Sign-up, checkout, coupon, booking, and OTP abuse |
API7 Server-Side Request Forgery | The API fetches attacker-supplied URLs | URL inputs, webhook targets, file imports |
API8 Security Misconfiguration | Unsafe defaults | CORS, verbose errors, missing headers, debug endpoints |
API9 Improper Inventory Management | Old or forgotten APIs stay live | Old versions, staging APIs, undocumented endpoints |
API10 Unsafe Consumption of APIs | Trusting third-party APIs too much | Validation of data received from partners and external services |
API Security Services We Offer
API Security Testing
Manual and automated testing of every endpoint, authenticated as each role and tenant.
GraphQL Security
Introspection exposure, query depth and complexity limits, batching attacks, and field-level authorization. See GraphQL API.
Webhook Security
Signature verification, replay protection, and SSRF checks on incoming and outgoing webhooks. See Webhooks.
Rate Limiting & Abuse Protection
Per-user and per-IP limits, quota design, and bot protection on sensitive flows such as login, sign-up, and checkout.
API Design Review
Authorization patterns fixed at the design level, so new endpoints are secure by default. See API Design.
Remediation
We fix findings in your codebase or pair with your team, then retest.
What You Get
An endpoint inventory, including undocumented and old versions we discover
Findings mapped to the OWASP API Security Top 10
Proof of each finding with request and response examples
Fix guidance for your framework: Node.js, Python, Java, Go, .NET, or PHP
A retest of fixed findings
A shareable summary for customers and auditors
What We Need From You
What to Share | Why It Helps |
API documentation: OpenAPI or Swagger file, Postman collection, or GraphQL schema | Helps us reach every endpoint quickly |
Test accounts for each role, in at least two tenants | Needed to test access between users and between customers |
A staging environment if possible | Keeps production data safe |
Written authorization and scope | Testing only happens with explicit permission |
Common Mistakes to Avoid
Instinct | Why It Doesn't Help | Do This Instead |
Trusting the frontend to hide data | Attackers call the API directly | Enforce authorization on the server for every request |
Checking login but not ownership | Logged-in users can still read other users' records | Check that the user may access each specific object |
Skipping rate limits | Enables brute force, scraping, and surprise cloud bills | Add per-user and per-IP limits on every endpoint |
Leaving old API versions running | Old versions often lack newer security fixes | Keep an inventory and retire old versions |
Relying only on an API gateway | Gateways handle authentication, not business authorization | Combine gateway controls with checks in your code |
How It Works
1. Scope and authorize
Endpoints, roles, and environments agreed in writing
2. Map endpoints
From your documentation, traffic, and discovery
3. Test
Each endpoint tested as each role and tenant
4. Report
Findings with proof, risk rating, and fixes
5. Fix and retest
We fix or guide your team, then confirm closure
Why Codersarts
We design and build APIs as well as test them, so every finding comes with a working code pattern for your stack, not just a warning. Testing only happens with written authorization and agreed scope.
Turnaround Time
Testing an API with up to about 50 endpoints typically takes 5 to 10 working days, plus 2 working days for the report. Larger or multi-API scopes are planned individually.
FAQ
What is the most common API vulnerability?
Broken Object Level Authorization (BOLA), number one on the OWASP API Security Top 10. An endpoint returns another user's data when the ID in the request is changed.
Which types of APIs do you test?
REST, GraphQL, gRPC, and SOAP APIs, plus webhooks and the APIs behind mobile apps.
How is API testing different from web application testing?
Web app testing goes through the user interface. API testing calls endpoints directly, which is how most data leaks are found, because attackers skip the interface too.
Will testing disrupt our API?
We prefer a staging environment. Production testing is scheduled, limited to agreed activities, and rate-limit tests are run with care.
How often should APIs be tested?
After every major release, whenever new endpoints or integrations are added, and at least once a year.
Is our project kept confidential?
Yes. Your data, code, and results stay confidential, and an NDA is available on request.
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