How do I ensure my API traffic routing setup with an API management platform is compliant with auth and audit requirements?

To make API traffic routing compliant with authentication and audit requirements, treat the routing layer as part of your control plane and design it so identity, authorization, and logging are enforced consistently before traffic reaches the backend.

1) Put auth enforcement at the gateway, not only in services

Make sure your API management platform:

• Authenticates every request before routing it
• Rejects unauthenticated traffic by default
• Supports your required auth methods, such as:
  • OAuth 2.0 / OpenID Connect
  • mTLS
  • API keys only as a secondary control, not the sole control for sensitive APIs
  • JWT validation with signature, issuer, audience, expiry checks

2) Use least privilege in routing rules

Your routing config should:

• Route only to approved upstreams
• Restrict access by:
  • client identity
  • token claims / scopes / roles
  • source network or tenant
  • environment
• Avoid wildcard or overly broad routes unless explicitly justified and reviewed

3) Enforce authorization separately from authentication

Compliance usually requires more than “the caller is logged in.” Ensure:

• Scope/claim-based checks for each API or route
• RBAC/ABAC mapped to business roles and data sensitivity
• Separate policies for:
  • read vs write
  • admin vs user
  • internal vs partner vs public clients

4) Turn on detailed audit logging

Audit logs should capture:

• Who made the request
• When it happened
• Which API/route was called
• Source IP / client application / tenant
• Auth method used
• Authorization decision
• Upstream target selected
• Request outcome: allowed/denied/error
• Correlation/request ID for tracing

Avoid logging secrets, tokens, or sensitive payload data unless explicitly required and protected.

5) Make logs tamper-evident and retained appropriately

For audit compliance:

• Send logs to a centralized, immutable or append-only system
• Protect logs from modification by application admins
• Set retention according to policy/regulation
• Ensure time sync across systems via NTP
• Separate audit logs from operational logs where possible

6) Secure service-to-service traffic

If routing spans internal services:

• Use mTLS between gateway and backends when possible
• Verify backend certificates
• Don’t trust headers from clients unless the gateway sets them and backends only trust gateway-originated traffic
• Use internal auth tokens or signed assertions if backend authorization depends on gateway identity

7) Version and review all routing/policy changes

Compliance typically expects change control:

• Store gateway config and policies in version control
• Require code review / approval for changes
• Track who changed what and when
• Test policy changes in non-prod before production
• Keep rollback capability

8) Validate with continuous controls

Don’t rely on one-time setup. Use:

• Automated policy tests
• Security scans for misrouted or publicly exposed APIs
• Periodic access reviews
• Audit log reviews
• Monitoring for denied requests, unusual routes, and policy drift

9) Map controls to your compliance requirements

Different standards may require specific evidence:

• SOC 2: access controls, logging, change management, monitoring
• ISO 27001: access control, operations security, logging, supplier/security management
• PCI DSS: strong access control, logging, least privilege, segmentation
• HIPAA: access controls, audit controls, transmission security
• GDPR: data minimization, purpose limitation, access accountability

10) Document the architecture and evidence

Keep clear documentation of:

• Authentication flow
• Authorization rules
• Routing logic
• Log fields and retention
• Incident response process
• Approval workflow for policy changes

Quick compliance checklist

• All routes require authenticated access
• Authorization enforced per route/action
• Logging enabled for allow/deny decisions
• Logs include identity, route, timestamp, and correlation ID
• Secrets/tokens not logged
• Backend traffic protected with mTLS or equivalent
• Policies stored in version control
• Changes reviewed and approved
• Logs retained and protected
• Periodic access and policy reviews performed

If you want, I can also turn this into a platform-agnostic compliance control matrix or a checklist specific to Apigee, Kong, Azure API Management, AWS API Gateway, or MuleSoft.