COSS
Domains

Add a custom tracking domain

POST
/v1/domains/{id}/tracking

Sets up a subdomain of the domain (e.g. links.acme.com) to serve open and click tracking. Publish the CNAME record in tracking.record; COSS then issues its certificate and checks it in the background, giving up after 72 hours. Open pixels and click redirects of emails sent from the domain (or its subdomains without a domain of their own) use the tracking domain while it is active, and the default tracking host otherwise. A domain has at most one tracking domain: remove it to use another hostname.

Authorization

bearerAuth
headerAuthorizationBearer <token>

A secret API key from the dashboard: coss_live_… for production environments, coss_test_… for sandbox environments.

Path Parameters

id*string

The domain's id.

Header Parameters

Coss-Version?"2026-10-10"

The API version (a date) to use for this request. Defaults to your organization's version, pinned to the latest one when it first used the API and upgraded from the dashboard. The SDK always sends the version it was built for.

Value in"2026-10-10"

Request Body

application/json
  1. body
hostname*string

A subdomain of the domain to serve tracking links from, without a scheme or path. Point it at COSS with the CNAME record the response lists.

Length1 <= length <= 200

Response Body

The domain, with its tracking domain and the CNAME to publish.

application/json
  1. response
object*"domain"
Value in"domain"
id*string
name*string

The domain, lower-cased.

status*string

pending while the records are being checked, verified once they are, temporary_failure after a transient DNS problem, and failed when verification gave up (72 hours) — restart it with the verify endpoint. deleting is a removal in progress.

Value in"pending""verified""temporary_failure""failed""deleting"
can_send*boolean

Whether live keys may send from this domain right now.

region*string|null
mail_from_domain*string

The envelope sender subdomain bounces come back to.

mail_from_status*string
Value in"pending""success""temporary_failure""failed"
records*array<>

The DNS records to publish, with the result of the last check.

created_at*string
Formatdate-time
last_checked_at*|
Formatdate-time
verified_at*|
Formatdate-time
failed_at*|
Formatdate-time
tracking*|null
import { Coss } from "coss";const coss = new Coss({  apiKey: process.env.COSS_API_KEY,  baseUrl: "https://api.coss.com",});const { data, error } = await coss.domains.tracking.create("dom_01k7c8m4q2f3e9v6t5r1n0p8yz", {  hostname: "links.acme.com",});
{  "object": "domain",  "id": "dom_01k7c8m4q2f3e9v6t5r1n0p8yz",  "name": "acme.com",  "status": "verified",  "can_send": true,  "region": "us-east-1",  "mail_from_domain": "send.acme.com",  "mail_from_status": "success",  "records": [    {      "priority": null,      "required": true,      "status": "verified",      "found": [],      "purpose": "dkim",      "type": "CNAME",      "name": "x7f3k2m9qp4ld8sv6hwz1nyc5rbtgj0e._domainkey.acme.com",      "value": "x7f3k2m9qp4ld8sv6hwz1nyc5rbtgj0e.dkim.amazonses.com"    },    {      "priority": 10,      "required": true,      "status": "verified",      "found": [],      "purpose": "mail_from_mx",      "type": "MX",      "name": "send.acme.com",      "value": "feedback-smtp.us-east-1.amazonses.com"    },    {      "priority": null,      "required": true,      "status": "verified",      "found": [],      "purpose": "mail_from_spf",      "type": "TXT",      "name": "send.acme.com",      "value": "v=spf1 include:amazonses.com ~all"    },    {      "priority": null,      "required": false,      "status": "verified",      "found": [],      "purpose": "dmarc",      "type": "TXT",      "name": "_dmarc.acme.com",      "value": "v=DMARC1; p=none;"    }  ],  "created_at": "2026-01-15T09:30:00.000Z",  "last_checked_at": "2026-01-15T09:42:10.000Z",  "verified_at": "2026-01-15T09:42:10.000Z",  "failed_at": null,  "tracking": {    "hostname": "links.acme.com",    "status": "active",    "record": {      "type": "CNAME",      "name": "links.acme.com",      "value": "track.coss.com",      "status": "verified",      "found": []    },    "message": null,    "created_at": "2026-01-15T09:45:00.000Z",    "last_checked_at": "2026-01-15T09:52:00.000Z",    "activated_at": "2026-01-15T09:52:00.000Z",    "failed_at": null  }}

Add a sending domain POST

Claims the domain for the organization and returns the DNS records to publish. Domains belong to the organization, not to one environment, so every API key of the organization sees the same domains. The records are checked repeatedly in the background and verification gives up after 72 hours; until the domain is `verified`, live keys cannot send from it.

Remove a sending domain DELETE

Removes the domain and its provider identity. Emails already sent are unaffected, but live keys can no longer send from it and the name becomes available again.