An API can expose business data through one overlooked route, even when the rest of the app is locked down. This API integration security checklist groups the work by lifecycle, so your team can check design, access, runtime controls, and response before release.
We analyzed 27 comments from Reddit and YouTube about API integration security and found that 33% mentioned IP whitelisting.
Start With API Threat-Modeling and Design Resources
Start with a map of what connects to what. List each API, its owner, its users, the data it handles, and the systems it can reach. Mark whether it’s public, partner-facing, or internal. An internal API still needs protection if another service or account can reach it.
Then sketch the main request paths. For each one, ask what could go wrong if a caller changes an ID, sends a huge payload, replays a request, or gets a token they shouldn’t have. Check how a threat could cross from the API into a database or another service. Record the likely impact and the control that should stop it.
A contract-first design gives developers a shared description of routes, fields, and responses before they write the integration. Keep the API definition in source control, and require a review when a change adds a route or exposes a new field. Our API design best practices cover clear contracts, versioning, and documentation as part of secure design.
For every route in the contract, note its authentication method, permitted roles, accepted input, and data returned. This makes it easier to spot a route that has no owner or a field that clients don’t need. It also gives reviewers a specific checklist to test against.
Verify it: Compare the API contract with the routes deployed in a test environment. Confirm every route has an owner and a stated access rule. Send a request to a route that should be private and check that it is denied.
Lakeway Web Development builds custom web and mobile applications, with built-in security measures and scalable architecture. For a new integration, we can help map the systems and define the security checks alongside the API design.
Use Identity, Access-Control, and Data-Privacy Checklists
Authentication confirms who or what is making a request. Authorization decides what that caller may do. Check both at the point where the API receives the request, then check permission again where sensitive records are read or changed.
- Require authentication: Protect private routes with a defined method, such as OAuth 2.0 or signed tokens. Verify token signature, expiry, issuer, and intended audience. Reject missing, expired, or malformed tokens.
- Limit permissions: Give each user, service, or partner only the access needed for its task. A report reader shouldn’t be able to edit customer records.
- Check each object: Test whether a signed-in user can change an ID in a URL and view another person’s record. This catches broken object-level authorization, often called BOLA.
- Protect credentials: Keep secrets out of source code. Set a rotation and revocation process, and make sure a former integration credential can no longer access the API.
Authorization needs checks at the object level, not only at the route. If a customer support user can open an order record, test whether that person can also alter its payment details. Use role or attribute rules that match the work each account performs.
Data protection starts with the response. Return only the fields a client needs for its task. Review error messages too, since stack traces and internal service names can reveal details that belong on the server, not in a client response.
Decide which data is sensitive before building the integration. A medical practice may handle health details that need special care, while a retail API may expose order and payment records. Set rules for encryption in transit and at rest, retention, and who may review access logs. Apply the relevant US federal and state requirements to your business and data; don’t assume one rule fits every organization.
Lakeway Web Development supports system integration and ongoing maintenance. A written access matrix can help your team and developer agree on which system, role, and record each connection is allowed to touch.
Verify it: Test with a valid user, a user with the wrong role, and no token. Try changing a record ID. Confirm each request gets only the access intended for that caller.
Find Runtime Protection, Gateway, and Cloud-Configuration Resources
Runtime controls check requests as they move through the system. Put an API gateway with route-level security controls or equivalent policy layer in front of exposed services when your architecture supports it. Set route-level limits, payload size limits, timeouts, and allowed methods. A login route may need tighter request limits than a read-only catalog route.
Use HTTPS for API traffic. For internal service calls, decide whether mutual TLS or another workload identity check fits the risk. Restrict network paths so a service can reach only the backends it needs. This is a Zero-Trust approach: verify each connection instead of assuming that internal traffic is safe.
Cloud services have shared responsibility boundaries. When using a managed API gateway, confirm who is responsible for securing API definitions, identity and access settings, and network configuration. Apply least privilege and minimize the exposed attack surface.
Apply that idea to whichever cloud platform hosts your API. Review gateway routes and policies after each change. Check that public routes are intentional, administrative routes have tighter access, and backend services aren’t reachable through an unexpected path. Don’t assume a gateway can replace checks inside the application.
Set rate limits and throttles by route and caller where possible. A burst of password reset attempts needs a different response from a burst of public product lookups. For operations that change money or create records, test retries carefully. Use an idempotency mechanism when repeating the same request could create duplicate effects.
Review security settings with a short configuration checklist: TLS, accepted methods, allowed origins, CORS rules, response headers, caching, and error handling. CORS controls which browser-based sites may read responses; it isn’t a substitute for authentication. Set it to the specific origins that need access.
Verify it: Send a request with an unapproved method, an oversized body, and a disallowed origin. Confirm the gateway or application rejects each request before it reaches sensitive backend logic.
Keep a current inventory of deployed API versions. Retire old routes once consumers have moved, and set a clear end date for versions that no longer receive support. Each live version adds another route that needs access rules and monitoring.
Build a Continuous Testing and Incident-Response Toolkit
Security checks should run before release and after changes to routes, permissions, or data fields. Add API tests to the build pipeline, so a change can’t pass simply because the app still returns a successful response.
- Test authentication with missing, expired, and altered credentials.
- Test authorization with a valid account that lacks the required role.
- Send malformed input, unexpected fields, and oversized payloads.
- Check rate limits, error messages, and repeated requests to sensitive operations.
- Scan dependencies and API definitions as part of routine build checks.
Use an API security risk checklist, not a pass-or-fail badge. Include checks for broken object-level authorization, broken authentication, excessive data exposure, unrestricted resource use, and security misconfiguration. Add a test case for each risk that applies to your API.
Log enough to trace a request: caller or service identity, route, outcome, time, and a request ID. Record failed sign-ins, denied access, rate-limit events, and changes to sensitive records. Don’t store full request bodies by default. Passwords, tokens, and private customer data can turn logs into another place attackers look.
Set alerts for a sudden rise in denied requests or a sharp change in traffic on a sensitive route. Monitoring, alerting, auditing changes, and automating security practices where possible can help flag behavior that needs a human review.
Write an incident plan before an alert arrives. Name who can disable a compromised credential, block a route, preserve logs, and notify the right internal owners. The plan should cover leaked API keys, unauthorized access, exposed records, and abuse of an API function. Include a way to restore service after containment.
For example, if a partner key appears in a public code repository, your response should be clear: revoke it, issue a replacement through the approved process, review access logs for use of the old key, and document the outcome. Test the plan with a tabletop exercise so each person knows their part.
Verify it: Run a failed-login alert test and an access-denial test. Confirm the events appear in logs with enough detail to investigate, but without tokens or sensitive payloads.
API Integration Security FAQ
What should an API integration security checklist include?
It should cover API design, authentication, authorization, data protection, input validation, runtime controls, testing, and incident response. Assign an owner to each API and record which routes expose sensitive data. Then define how your team will test both allowed requests and requests that should be blocked.
How do I test API authentication and authorization?
Test them separately. Send a request without a token, then use an expired or invalid token and confirm access is denied. Next, sign in as a valid user who lacks permission and try to view or change a record they don’t own. The API should reject the request without returning protected data.
What is BOLA in API security?
BOLA means broken object-level authorization. It happens when an API checks that a caller is signed in but fails to check whether that person may access the specific record they requested. Test it by changing a record ID in a request and confirming the API doesn’t reveal or change another user’s data.
How often should API security tests run?
Run automated checks with every relevant code or API contract change, and repeat manual review when access rules or sensitive data flows change. Also test after a security incident or a major configuration update. The exact schedule depends on your API’s risk, release process, and business needs.
Conclusion
Use this checklist as a release gate: every route needs a clear owner, access rule, and test. If your business is planning a new connection or reviewing an older one, Lakeway Web Development can help map the systems and build security checks into the work. Start by inventorying your API routes and assigning an owner to each.