API Reference
Audiences
Billing
Broadcasts
Contacts
- Create a contact property POST
- Create a contact's preference links POST
- Delete a contact property DELETE
- Delete a contact DELETE
- Export contacts as CSV GET
- Retrieve a contact property GET
- Retrieve a contact's topics GET
- Retrieve a contact GET
- Import contacts in bulk POST
- List contact properties GET
- List contacts GET
- Resend a contact's confirmation email POST
- Update a contact property's fallback PATCH
- Update a contact's topics PATCH
- Update a contact PATCH
- Create or update a contact POST
Dedicated ips
Domains
- Add a sending domain POST
- Receive email at a domain POST
- Add a custom tracking domain POST
- Remove a sending domain DELETE
- Stop receiving email at a domain DELETE
- Remove a custom tracking domain DELETE
- Retrieve a DMARC report GET
- Retrieve a domain's DMARC status GET
- Retrieve a sending domain GET
- List a domain's DMARC reports GET
- List sending domains GET
- Check a domain's DNS records now POST
Email templates
- Create an email template POST
- Delete an email template DELETE
- Retrieve a template's draft GET
- Retrieve a template version GET
- Retrieve an email template GET
- List a template's versions GET
- List email templates GET
- Publish a template's draft POST
- Restore a template version POST
- Update a template's draft PUT
- Update an email template PATCH
Emails
Hooks applications
Hooks endpoints
Hooks event types
Hooks messages
Hooks portal
Log drains
Receiving
Risk
- Check an email address POST
- Check an IP address POST
- Check a rate limit POST
- Classify content POST
- Assess an event POST
- Report an assessment's outcome POST
- Create a rate limit bucket POST
- Add an allow or block list entry POST
- Create a rule POST
- Delete a rate limit bucket DELETE
- Remove a list entry DELETE
- Delete a rule DELETE
- Forget a user DELETE
- Retrieve an assessment GET
- Retrieve the calibration GET
- Retrieve a rate limit bucket GET
- Retrieve a list entry GET
- Retrieve a rule GET
- Retrieve the risk settings GET
- List assessments GET
- List rate limit buckets GET
- List allow and block list entries GET
- List rules GET
- Update a rate limit bucket PATCH
- Update a rule PATCH
- Update the risk settings PATCH
Segments
Suppressions
Topics
Tracking
Webhook endpoints
- Create a webhook endpoint POST
- Open a webhook listener POST
- Delete a webhook endpoint DELETE
- Close a webhook listener DELETE
- Retrieve a delivery GET
- Retrieve a webhook endpoint GET
- List an endpoint's deliveries GET
- List webhook endpoints GET
- Poll a webhook listener POST
- Recover failed deliveries POST
- Retry a delivery POST
- Roll a signing secret POST
- Update a webhook endpoint PATCH
Update a contact's topics
PATCH
/v1/contacts/{id}/topics
Records the contact's choices for the topics given; the others keep theirs.
bearerAuthheader
AuthorizationBearer <token>A secret API key from the dashboard: coss_live_… for production environments, coss_test_… for sandbox environments.
id*stringThe contact's id, or its address (URL-encoded).
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"application/json- body
- body
- …
topics*array<>Items
1 <= items <= 100The topics.
application/json- response
- response
- …
object*"contact_topics"Value in
"contact_topics"contact_id*stringtopics*array<>import { Coss } from "coss";const coss = new Coss({ apiKey: process.env.COSS_API_KEY, baseUrl: "https://api.coss.com",});const { data, error } = await coss.email.contacts.updateTopics("contact_01k7c8m4q2f3e9v6t5r1n0p8yz", { topics: [ { topic: "product", status: "opted_out", }, ],});{ "object": "contact_topics", "contact_id": "contact_01k7c8m4q2f3e9v6t5r1n0p8yz", "topics": [ { "topic": "newsletter", "name": "Newsletter", "subscribed": true, "choice": null }, { "topic": "product", "name": "Product updates", "subscribed": false, "choice": "opted_out" } ]}