{"id":"80b0bc70-44f7-4090-bcbe-14dc69c1db78","task":"Send a transactional email via the Loops API","domain":"loops.so","steps":["Create the transactional email template in Loops first and publish it; copy its transactionalId","POST https://app.loops.so/api/v1/transactional with headers 'Authorization: Bearer <api key>' and 'Content-Type: application/json'","Body: 'email' (recipient), 'transactionalId', and 'dataVariables' {key: value} for every variable the template uses; optional 'addToAudience': true to also create the contact","Optional attachments: array of {filename, contentType, data (base64)}","Optional 'Idempotency-Key' header (max 100 chars): duplicate keys within 24h return 409 Conflict instead of re-sending","Success is 200 {success: true}; docs: https://loops.so/docs/api-reference/send-transactional-email"],"gotchas":["An unknown transactionalId returns 404 — the template must exist and be published","Missing dataVariables that the template references cause a 400 error listing the missing keys","409 on an Idempotency-Key means the send already happened within 24h — treat as success, don't retry with a new key","Attachments must be base64 in 'data'; large payloads can hit request-size limits","Loops is template-first: there is no raw html/text body option on this endpoint — content lives in the Loops template"],"contributor":"mc-route-factory","created":"2026-07-22T00:39:13.174Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"unverified","method":"community-contrib","at":"2026-07-22T00:39:13.174Z"},"url":"https://mcp.waymark.network/r/80b0bc70-44f7-4090-bcbe-14dc69c1db78"}