API Gateway

The gateway acts as the Policy Enforcement Point (PEP) , offloading security from microservices. It intercepts every request to validate credentials before they reach the backend.

• Token Introspection: Validates JWT, OAuth2, and API Key integrity at the edge.
• Scoped Access: Enforces fine-grained permissions, ensuring a consumer only accesses the specific Training Corpus Manifest their license permits.
• Credential Lifecycle: Integrates with Key Provisioning services to reject expired or revoked tokens without backend involvement.

Protects backend Licensing Microservices from overload and ensures fair resource allocation per Monetization Tier using sophisticated algorithms.

• Token Bucket Algorithm: Allows controlled bursts of traffic while enforcing a steady long-term request rate.
• Quota Management: Tracks data volume ingestion against a Service Level Agreement (SLA) , returning 429 Too Many Requests when limits are breached.
• Throttling: Gracefully degrades service for non-critical consumers during peak load to prioritize high-tier licensees.

Decouples the public Content Licensing API endpoint from the internal implementation, enabling seamless backend evolution.

• Path-Based Routing: Directs /license/verify to the Entitlement Service and /data/download to a storage proxy.
• Header/Auth Routing: Sends requests from a specific partner to a dedicated, isolated backend stack based on the JWT claim.
• API Composition: Aggregates data from multiple services (e.g., license status + usage metrics) into a single, coherent client response.

Provides a single choke point for generating immutable telemetry, crucial for AI Audit Logging and billing reconciliation.

• Structured Logging: Captures every request/response payload, latency, and Idempotency Key for financial-grade transaction tracing.
• Metrics Aggregation: Exports request count, error rate, and latency percentiles to monitoring systems to verify SLA compliance.
• Distributed Tracing: Injects correlation IDs to track a single licensing transaction across multiple backend microservices.

Protects the Policy Decision Point (PDP) and backend data stores from malicious clients and web scraping attacks.

• Request Validation: Strictly validates input schemas and content types, dropping malformed requests before they hit the Licensing Microservice.
• IP Reputation & Allow/Deny Lists: Blocks traffic from known malicious sources or unauthorized AI Crawler IP ranges.
• TLS Termination: Handles the computational overhead of encrypting and decrypting HTTPS traffic, offloading this burden from backend services.

Bridges the gap between modern client expectations and legacy or specialized backend service interfaces.

• Protocol Bridging: Accepts external HTTP/2 or gRPC-web calls and translates them to internal gRPC for low-latency service-to-service communication.
• Message Transformation: Converts XML payloads from legacy systems into JSON for modern Content Licensing API consumers.
• Response Caching: Stores frequently accessed, immutable data like a Data Card to reduce latency and backend load.

The architectural component that intercepts every API request to a protected licensing resource. The gateway acts as the PEP, physically blocking traffic before it reaches the backend. It queries the Policy Decision Point (PDP) to determine if a request is authorized.

• Function: Enforces decisions (allow/deny) without making them.
• Flow: Intercept request → Forward to PDP → Enforce verdict.
• Example: A gateway rejecting a call because the attached JWT lacks a valid data_read scope.

The primary authentication mechanism for machine-to-machine licensing APIs. A JSON Web Token (JWT) is a compact, URL-safe token that carries cryptographically signed claims. The gateway validates the signature and expiry without querying a database.

• Stateless: The token itself contains the authorization context.
• Claims: Include iss (issuer), exp (expiry), and custom scope claims.
• Validation: Gateway checks the signature against a public JWKS endpoint.

A traffic control mechanism to prevent abuse and enforce Quota Management. The Token Bucket Algorithm is the standard implementation: a bucket refills with tokens at a fixed rate, and each request consumes a token.

• Burst Handling: Allows short traffic spikes up to the bucket's capacity.
• Response: Returns HTTP 429 Too Many Requests with a Retry-After header.
• Granularity: Limits can be per API key, per IP, or per licensed dataset.

A permissioning model where an access token is granted limited privileges. The Entitlement Service acts as the PDP, evaluating the token's claims against the requested resource at runtime.

• Fine-Grained: A token may allow reading dataset-A but not dataset-B.
• Dynamic: Entitlements can change mid-session; the gateway re-validates on each request.
• OAuth2: The Client Credentials Grant is the standard flow for obtaining these scoped tokens.

A critical reliability pattern for payment and licensing transactions. An Idempotency Key is a unique client-generated UUID sent in the Idempotency-Key header. The gateway or upstream service stores the response of the first request.

• Mechanism: If the same key is received again, the stored response is returned immediately.
• Use Case: Prevents double-charging when a billing request times out and is retried.
• Storage: Keys are typically stored with a 24-hour expiry.

The centralized interface for the API Key Provisioning lifecycle. This is where a licensee's developers generate, rotate, and monitor their credentials.

• Self-Service: Automates onboarding and reduces administrative overhead.
• Key Rotation: The portal facilitates License Key Rotation, allowing a new key to be issued before the old one is revoked to ensure zero-downtime transitions.
• Observability: Displays real-time usage against the Monetization Tier quota.