API Versioning & Deprecation Policy — SMMAiSetup

*Effective Date: January 1, 2026*

SMMAiSetup is committed to maintaining stable, predictable API surfaces that autonomous AI agents and enterprise developers can rely on without fear of unexpected breaking changes.

1. REST API Versioning Scheme

• **URI Path Versioning**: Major API versions are declared explicitly in the URI path (`/api/v1/*`, `/api/v2/*`).
• **Header Versioning**: Clients may also pass `API-Version: 2026-01-01` to declare strict compatibility pins.
• **Backward Compatibility**: Non-breaking changes (new optional fields, additional endpoints) are added directly to the active version without incrementing the major version.

2. Deprecation Schedule & Advance Notice

• **Minimum 6-Month Notice**: Any endpoint scheduled for deprecation or removal will be announced at least 6 months prior to sunset.
• **RFC 8594 Standard Signaling**: Deprecated endpoints will continuously return standard HTTP response headers:
• `Sunset: <HTTP-date>` (RFC 8594 timestamp when the endpoint will be turned off)
• `Deprecation: @<Unix-timestamp>` (Date when the deprecation became active)
• `Link: <https://smmaisetup.com/deprecation-policy>; rel="deprecation"`
• **Zero Silent Breaking Changes**: APIs will never be altered or shut down without public RFC signaling.

3. Supported Core Endpoints (v1)

• `GET /api/v1/health` — System status and version verification.
• `GET /api/v1/services` — Public capability catalog.
• `GET /api/v1/pricing-plans` — Pricing tiers and credit plans.
• `POST /api/v1/auth/agent-key` — Self-serve trial API token generator.
• `POST /api/v1/sandbox/order` — Simulated order testing in sandbox mode.
• `POST /api/mcp` — Model Context Protocol Streamable HTTP endpoint.
• `GET /openapi.json` — OpenAPI 3.1 machine-readable specification.