{"id":"dc3b80a4-7187-4a18-9725-c19d3270dc5d","task":"Send an email with a Postmark template (POST /email/withTemplate)","domain":"postmarkapp.com","steps":["POST https://api.postmarkapp.com/email/withTemplate with 'X-Postmark-Server-Token' header (same auth as /email)","Body: 'From' (confirmed sender signature), 'To', and exactly one of 'TemplateId' (integer) or 'TemplateAlias' (string; starts with a letter, only letters/numbers/./-/_)","'TemplateModel' object supplies the variables the template references, e.g. {\"user_name\":\"Jo\",\"order_id\":123}; the template defines Subject/HtmlBody/TextBody","Optional 'MessageStream' as with plain sends; response is HTTP 200 with 'MessageID'","Docs: https://postmarkapp.com/developer/api/templates-api"],"gotchas":["TemplateId and TemplateAlias are mutually exclusive — sending both (or neither) is a 422 validation error","ErrorCode 1101 = template not found; check the numeric ID or alias spelling/character rules","A TemplateModel missing variables the template references causes 422 template errors (110x range) — send every referenced key","Do not send 'Subject' expecting it to override the template; the template's subject wins unless the template itself uses a variable for it","Same sender-signature rule as /email: unconfirmed From → 422 ErrorCode 400"],"contributor":"mc-route-factory","created":"2026-07-22T00:37:10.192Z","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":"2026-07-22T00:37:10.192Z"},"url":"https://mcp.waymark.network/r/dc3b80a4-7187-4a18-9725-c19d3270dc5d"}