---
type: API
title: Sending domains API (partner integrations)
description: Create, verify and manage sending domains for apps that send as their customers' domains — one account, many domains, one key with the send_any_domain scope.
resource: https://euromailing.com/api/v1/sending_domains
tags: [sending-domains, partner, dkim, spf, dmarc, api]
timestamp: 2026-08-08T00:00:00Z
---

# Sending domains API

For **partner integrations** — one Euromailing account that sends on
behalf of many customer domains (e.g. a SaaS mailing as each customer's
own domain). One account, many `SendingDomain`s, **one API key** with the
`transactional:send_any_domain` scope (validates the From against every
verified domain on the account) plus `sending_domains:read|write`.

**Euromailing is the source of truth for verification.** Show the DNS
records to your customer, then poll status or trigger a check — never
verify the customer's DNS yourself.

## Create a domain

```
POST /api/v1/sending_domains
{ "domain": "coachklant.nl" }
```

`201` with ready-made DNS records the customer adds at their registrar:

```json
{
  "id": "…", "domain": "coachklant.nl", "status": "pending", "verified": false,
  "dns_records": [
    { "purpose": "dkim", "type": "CNAME",
      "host": "euromailing._domainkey.coachklant.nl",
      "value": "coachklant-nl._dkim.euromailing.com" },
    { "purpose": "spf", "type": "TXT", "host": "coachklant.nl",
      "value": "v=spf1 include:spf.euromailing.com ~all",
      "include_token": "include:spf.euromailing.com",
      "note": "Add only the include mechanism to an existing v=spf1 record; never create a second SPF record." },
    { "purpose": "dmarc", "type": "TXT", "host": "_dmarc.coachklant.nl",
      "value": "v=DMARC1; p=none; rua=mailto:dmarc@euromailing.com",
      "note": "Only add if no _dmarc record exists; do not overwrite an existing DMARC record." }
  ]
}
```

Notes:
- **DKIM is a single CNAME.** Euromailing publishes its side automatically,
  so the customer adds exactly one record.
- **SPF: use `include_token`, not `value`.** Read the customer's live
  `v=spf1` record and merge the token in — there must be exactly one SPF
  record.
- **DMARC: don't overwrite.** Only add when none exists.

## Check / verify status

```
GET  /api/v1/sending_domains/coachklant.nl          # poll
POST /api/v1/sending_domains/coachklant.nl/verify   # fresh DNS check
```

```json
{ "domain": "coachklant.nl", "verified": false,
  "dkim_published_at": "…", "dns_verified_at": null,
  "records": [ { "purpose": "dkim", "ok": true },
               { "purpose": "spf", "ok": false },
               { "purpose": "dmarc", "ok": false } ] }
```

Minimum you need is `verified`; the per-record `ok` is for a nicer UI.

## List / delete

```
GET    /api/v1/sending_domains          # all domains on the account
DELETE /api/v1/sending_domains/coachklant.nl   # 204, when a customer leaves
```

## Sending once verified

With a partner key, `POST /api/v1/transactional_emails` accepts a `from`
on **any verified domain** on the account — no per-domain key needed. See
[the transactional API](transactional-emails.md) (partner mode). A From
domain that isn't on the account returns `from_domain_not_on_account`; one
that exists but isn't verified returns `sending_domain_unverified`.

## Rails

The `euromailing-rails` gem (≥ 0.2.0) wraps all of this:
`client.create_sending_domain`, `sending_domain`, `verify_sending_domain`,
`delete_sending_domain`, `sending_domains`. See [the Rails guide](../guides/rails-gem.md).