MailChannels Email API (Send + Delivery Events)

Environment

Required:

MAILCHANNELS_API_KEY (send in X-Api-Key)
MAILCHANNELS_ACCOUNT_ID (aka customer_handle)

Optional:

MAILCHANNELS_BASE_URL (default: https://api.mailchannels.net/tx/v1), MAILCHANNELS_WEBHOOK_ENDPOINT_URL

Domain Lockdown (DNS)

Create a TXT record for each sender domain:

Host: _mailchannels.<your-domain>
Value: v=mc1; auid=<YOUR_ACCOUNT_ID>

API Quick Reference

Base URL: ${MAILCHANNELS_BASE_URL:-https://api.mailchannels.net/tx/v1}

Send: POST /send
Send async: POST /send-async
Webhook: POST /webhook?endpoint=<url>, GET /webhook, DELETE /webhook, POST /webhook/validate
Public key: GET /webhook/public-key?id=<keyid>

Sending Email

Minimum payload fields: personalizations, from, subject, content. Use /send for normal traffic and /send-async for queued/low-latency; both produce webhooks. Persist MailChannels correlation IDs (e.g., request_id).

Delivery Events (Webhooks)

MailChannels POSTs a JSON array. Common fields: email, customer_handle, timestamp, event, request_id. Bounce fields often include: recipients, status, reason, smtp_id.

Moltbot Hooks Routing

Enable hooks in ~/.clawdbot/moltbot.json.
Map /hooks/<path> to an agent action via hooks.mappings and optional transform.
Enroll the public endpoint in MailChannels /webhook?endpoint=....

Webhook Signature Verification

Headers: Content-Digest, Signature-Input, Signature. Steps:

Parse Signature-Input (name, created, alg, keyid).
Reject stale created values.
Fetch public key by keyid.
Recreate the RFC 9421 signature base.
Verify ed25519 signature (avoid hand-rolling). Also verify JSON body is an array and every event has customer_handle == MAILCHANNELS_ACCOUNT_ID.

Correlation + State Updates

Store your internal message ID + MailChannels IDs (e.g., request_id, smtp_id). Update delivery state from events: processed, delivered, soft-bounced, hard-bounced, dropped. Operational tips: respond 2xx quickly, process async, store raw events, dedupe retries.

Mailchannels