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Internal API gateway

ID MOD-075
System SD07
Repo bank-platform
Build status Deployed
Deployed Yes
Last commit bbdfbac46a1b5cf6dc25b4c7cd428a8daa669d03

The internal API gateway is the single entry point for all service-to-service and app-to-backend communication within the platform. Every API call from the customer app, the back-office app, and inter-service integrations passes through this gateway, which handles TLS termination, service authentication, rate limiting, request routing, API version negotiation, and request logging before forwarding to the target service.

Unlike the Open Banking gateway (MOD-061) — which handles external third-party CDR access — and the JWT RBAC module (MOD-044) — which handles token validation — the internal gateway owns the routing and reliability layer: circuit breaking, retry with backoff, timeout enforcement, and canary routing for deployments. It is the chokepoint that prevents any single misbehaving service from degrading the platform, and the place where cross-cutting concerns (logging, tracing header injection, correlation ID stamping) are applied uniformly.

API versioning is managed here: multiple versions of a service can be live simultaneously, with the gateway routing requests to the correct version based on the Accept or API-Version header. Deprecation notices are injected as response headers so consumers can track sunset timelines without consulting documentation.


Module dependencies

Depends on

Module Title Required? Contract Reason
MOD-044 JWT role-based access control Required Service-to-service request authentication is validated using JWT tokens issued by the RBAC module.
MOD-045 Secrets & key management Required mTLS certificates and service credentials used for mutual authentication are managed by the secrets module.
MOD-104 AWS shared infrastructure bootstrap Required AWS shared infrastructure provisioned by MOD-104 (EventBridge buses, S3, KMS, Kinesis, Cognito) is required before this module can be deployed.

Required by

Module Title As Contract
MOD-061 Open banking API platform Hard dependency
MOD-068 Authentication & session management Hard dependency
MOD-176 Snowflake read API service Hard dependency
MOD-177 SD06 risk dashboard renderer Hard dependency

Policies satisfied

Policy Title Mode How
DT-001 Information Security Policy GATE All service-to-service traffic passes through TLS-terminated endpoints with mutual authentication — no plaintext internal API calls are permitted.
DT-002 Cybersecurity Policy GATE Rate limiting and request signing enforce that only registered, authenticated services can call platform APIs — unauthenticated requests are rejected at the gateway.

Capabilities satisfied

Capability Title Mode How
CAP-121 API rate limiting & throttling GATE Enforces per-service and per-consumer rate limits, returning 429 responses before upstream services are reached — protects backend services from traffic spikes and abuse.
CAP-122 API versioning & request routing AUTO Routes requests to the correct service version based on the API version header, supporting multiple live versions simultaneously during migration windows.

Part of SD07 — Data Platform & Governance Infrastructure Compiled 2026-05-22 from source/entities/modules/MOD-075.yaml