Isolated test environment

Validate safely before touching calendar data.

The always-available contract sandbox cannot read or write account data. A named staging stage supports end-to-end testing only while that isolated deployment exists.

Safe verification surfaces

No-write capabilities: https://api.twelvemonthcalendar.com/v1/sandbox
Validate event payload: POST https://api.twelvemonthcalendar.com/v1/sandbox/validate-event

Conditional isolated stage (replace <stage> with an active deployed slug)
Web: https://<stage>.twelvemonthcalendar.com
REST: https://api-<stage>.twelvemonthcalendar.com/v1
OpenAPI: https://api-<stage>.twelvemonthcalendar.com/v1/openapi.json
MCP: https://mcp-<stage>.twelvemonthcalendar.com/mcp

There is no permanently public staging environment. Verify /health, /v1/openapi.json, and /v1/sandbox before use. Never reuse production credentials or assume stage data persists.