PostagedResources
Changelog
What changed in the APIs, and when.
Changes
Dated entries, newest first. Each names what changed and which API it affects. Changes to /v1 only add things: see Versioning.
| Date | Affects | Change |
|---|---|---|
| 2026-10-13 | Dynamic Audience API | A response that would be larger than 4 MB now lists only the recipients that were not mailed or were mailed with a warning, and adds results_truncated: true. summary still counts every recipient. A stored response that mailed nobody is no longer replayed. |
| 2026-10-13 | Integrations push API, Integrations MCP server | warnings now holds one entry per field and code, with a count and up to 5 example externalIds; index and externalId name the first. Every dropped value is still listed by GET /sync/rejections with type=warning. |
| 2026-10-13 | Dynamic Audience API | A campaign whose design is still an AI draft is refused with 409 design_cannot_render and the message "Open and save this AI draft in the designer before using it in a campaign." Nothing is mailed or charged. |
| 2026-10-13 | Dynamic Audience API | New reason unsupported_characters: a recipient whose values hold a character the text box's font can't print is not mailed or charged. New warning codes text_unmeasurable and text_curve_too_long: the card still mails in full. |
| 2026-10-13 | All APIs | Developer docs published. The OpenAPI description is at /openapi.json. |
| 2026-10-13 | Integrations MCP server, Formula MCP server | Both MCP servers now answer notifications with 202 and send WWW-Authenticate with every 401. |
| 2026-10-13 | Integrations push API, Integrations MCP server, Formula MCP server | 429 responses from the push API and both MCP servers now include Retry-After: 60. |
| 2026-10-13 | Dynamic Audience API, Formula MCP server | Integration keys (pk_int_) no longer work with POST /api/v1/recipients or the Formula MCP server. Use a Full access key to send recipients. |