---
title: "Add a sending domain"
method: POST
path: "/api/v1/domains"
tags: ["Domains"]
---

# Add a sending domain

`POST /api/v1/domains`

## Request

- Base URL: `https://api.sendly.now`
- URL: `https://api.sendly.now/api/v1/domains`
- Auth: one of:
  - HTTP bearer
  - API key in cookie `better-auth.session_token`
  - OAuth 2 (authorization code, authorization URL `https://app.sendly.now/api/auth/oauth2/authorize`, token URL `https://app.sendly.now/api/auth/oauth2/token`, scopes: `domains:write`)

Register a domain and start SES DKIM verification. The response carries the identity as created — `verified` is false, because nothing is verified until the DKIM records are published in the domain's DNS and SES resolves them. Poll `/api/v1/domains/{id}/verify` after publishing them.

`region` pins the SES region. The first domain a project adds LOCKS the project to that region and every later domain must match it — a project split across regions would have its SES configuration diverge silently.

`stream` assigns the identity to transactional or marketing traffic at creation; omit it to leave the identity serving both. `stream_default` makes it the project's default for that stream and therefore requires `stream` — sending it alone answers `422 validation_error` rather than being ignored.

A host already registered — to this project or to another — answers `409 conflict` when the caller can already send from it and `403 project_access_denied` when it belongs elsewhere. A subdomain whose registrable root is held by a suspended project is refused the same way.

Requires the `domains:write` scope — Add and remove sending domains, and trigger verification.

## Request body

- DomainV1Create: Body for POST /api/v1/domains.
  - `domain` string, required
  - `region` 'us-east-1' | 'us-west-2' | 'eu-west-1': AWS SES region for the project. Once a domain is added the region is locked and cannot be changed.
  - `stream` 'TRANSACTIONAL' | 'MARKETING': Which traffic a sending identity carries. An identity with no stream serves both, which is how every domain added before per-stream identities behaves.
  - `stream_default` boolean: Make this the project's default identity for `stream`. Requires `stream`.

## Response `201`

The registered sending domain, awaiting DNS

- DomainV1: A sending domain as exposed on the v1 API.
  - `created_at` string, date-time, required
  - `default_from_address` string, nullable, required
  - `default_from_name` string, nullable, required: The display name recipients see beside any address on this domain when a send names none. `null` falls back to the project name.
  - `dkim_verified` boolean, required
  - `domain` string, required
  - `id` string, uuid, required
  - `mail_from_domain` string, nullable, required
  - `mail_from_domain_status` string, nullable, required: SES's CustomMailFromStatus for `mail_from_domain` — the subdomain that carries the bounce path, NOT the status of any From address.
  - `region` string, nullable, required
  - `stream` 'TRANSACTIONAL' | 'MARKETING', nullable, required: Which traffic a sending identity carries. An identity with no stream serves both, which is how every domain added before per-stream identities behaves.
  - `stream_default` boolean, required
  - `updated_at` string, date-time, required
  - `verified` boolean, required

## Other responses

- `401`: `invalid_api_key` or `invalid_session` — missing or invalid credentials.
- `403`: `scope_missing`, `project_access_denied`, or `project_disabled`.
- `409`: `conflict` — this domain is already registered to a project you can send from.
- `422`: `validation_error` — query, path, or body parameters did not match the schema.
- `429`: `rate_limited` — see `Retry-After` and the `RateLimit` headers.
- `500`: `internal_error`.
- `502`: `internal_error` — AWS SES rejected the identity setup (unusable credentials, a missing IAM permission, or a refusal on Amazon's side). No domain row is written, and the request is not at fault: retrying it unchanged will not help.

---

[API](https://skmtc.dev/sendly/apis/sendly-api.md) · [All operations](https://skmtc.dev/sendly/apis/sendly-api/llms.txt) · [OpenAPI document](https://skmtc.dev/sendly/apis/sendly-api/revisions/ce7cfb7f7c7e?raw)