Agent-Skills.md

Agent Skills: Setting up a Mailtrap sending domain

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UncategorizedID: mailtrap/mailtrap-skills/setting-up-sending-domain

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mailtrap/mailtrap-skills
mailtrap
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pnpm dlx add-skill https://github.com/mailtrap/mailtrap-skills/tree/HEAD/skills/setting-up-sending-domain

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skills/setting-up-sending-domain/SKILL.md

Skill Metadata

Name
setting-up-sending-domain
Description
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Setting up a Mailtrap sending domain

Overview

You must add and verify a domain you control before live sending. Mailtrap shows every DNS record required for that domain in the UI: add the complete set as given (do not cherry-pick). After DNS verifies, complete the compliance step if requested.

Subdomain vs root: add the exact hostname you will use in the From address. If you send from notifications.mycompany.com, add that subdomain as the sending domain—not only mycompany.com, unless you truly send from the root domain.

For step-by-step clicks at common hosts, open the matching guide on Sending domain setup (Cloudflare, Route 53, etc.) and follow it alongside the live UI values.

Related skills: authorizing-api-requests (tokens, env vars, account_id resolution), sending-emails (after domain is ready).

When to use

  • New Sending Domains setup, stuck verification, or compliance questions
  • DNS at Cloudflare, AWS, Google, Namecheap, GoDaddy, DigitalOcean, etc.

When not to use

  • Sandbox-only testing without a custom domain (see testing-with-sandbox)

Authorization

The Sending Domains API calls below need Authorization: Bearer $MAILTRAP_API_TOKEN and an $MAILTRAP_ACCOUNT_ID in the path. Token scope, storage, and the one-liner that resolves $MAILTRAP_ACCOUNT_ID from GET https://mailtrap.io/api/accounts are covered in skill authorizing-api-requests.

Automating setup (API and DNS providers)

Prefer this path when building scripts or AI-assisted automation:

  1. DNS records and status via API — Use the Sending Domains API:
  • GET https://mailtrap.io/api/accounts/$MAILTRAP_ACCOUNT_ID/sending_domains — lists domains
  • GET https://mailtrap.io/api/accounts/$MAILTRAP_ACCOUNT_ID/sending_domains/{sending_domain_id} — returns dns_records (each with type, name, value, and verification status) and dns_verified. Poll after you publish DNS.
  1. Create domain via API —
  • POST https://mailtrap.io/api/accounts/$MAILTRAP_ACCOUNT_ID/sending_domains with domain_name when your flow provisions domains programmatically.
  1. Publish DNS programmatically —
  • Create the returned records at your DNS host using their API (e.g., Cloudflare API, AWS Route 53, Google Cloud DNS) or IaC. Align record names and values exactly with the API response.

Human fallback: Sending Domains > Add domain > copy values into the registrar UI > Verify when API automation is not available.

Workflow (summary)

  1. Sending Domains > Add domain and enter the domain name.
  2. Obtain required records from the UI or Sending Domains API; create all listed records at your DNS host exactly as shown (names, types, values).
  3. Wait for DNS propagation. If verification stays pending, use dig, nslookup, or an online DNS lookup to confirm each record is visible publicly before clicking Verify again.
  4. Complete the compliance flow when prompted.

Product walkthrough: Sending domain setup.

DNS provider guides (documentation)

Mailtrap publishes click-path guides for common providers. Open the page that matches the user's DNS host and follow it together with the live UI records:

If the user's provider is not listed, the same rule applies: copy every record from Mailtrap into the DNS zone that serves the From domain.

Important DNS caveat (proxied DNS)

If your DNS provider proxies records (orange-cloud on Cloudflare, similar CDN/proxy modes elsewhere), verification-related records must be DNS-only (grey cloud / non-proxied) unless Mailtrap documentation explicitly allows proxying—proxied CNAMEs and similar often break SPF/DKIM verification. The same constraint applies to any host that fronts DNS with a proxy.