---
title: "Create a topic."
method: POST
path: "/topics"
tags: ["Topics"]
---

# Create a topic.

`POST /topics`

## Request

- Base URL: `https://api.maildroppa.com` (the document declares no server; this is the origin it was published from)
- URL: `https://api.maildroppa.com/topics`
- Auth: API key in header `X-API-Key`

Creates an active topic appended to the catalog; optionally enrolls all existing subscribers.

## Request body

- AddTopic: Creates a topic; existing subscribers join only when explicitly requested.
  - `label` string: Label shown to readers.
  - `description` string: Optional description shown to readers.
  - `enrollExistingSubscribers` boolean: Enroll all existing subscribers into the new topic. Defaults to false.

## Response `200`

Topic created.

- Topic: Subscription topic that readers can subscribe to and unsubscribe from individually.
  - `id` string, uuid
  - `label` string: Label shown to readers on forms and the preference page.
  - `description` string: Optional description shown to readers.
  - `position` integer: Catalog position; gaps are allowed.
  - `status` 'ACTIVE' | 'ARCHIVED'
  - `archivedAtUtc` string, date-time
  - `defaultTopic` boolean: Whether this is the tenant default topic.
  - `subscribedCount` integer: Subscribers currently subscribed to the topic.
  - `optedOutCount` integer: Subscribers who opted out of the topic themselves.
  - `enrollmentRunning` boolean: Whether existing subscribers are currently being enrolled into the topic.
  - `enrollment` TopicEnrollmentDto
    - `status` 'RUNNING' | 'COMPLETED' | 'FAILED'
    - `startedAtUtc` string, date-time
    - `addedSubscriberCount` integer

## Other responses

- `400`: Invalid topic, duplicate label or active topic limit reached.
- `401`: Not Authorized
- `403`: Not Allowed
- `409`: Subscriber bulk operation prevents catalog changes or enrollment.
- `428`: Accept the customer agreements in the app before using API keys.

---

[API](https://skmtc.dev/maildroppa/apis/maildroppa-api-beta.md) · [All operations](https://skmtc.dev/maildroppa/apis/maildroppa-api-beta/llms.txt) · [OpenAPI document](https://skmtc.dev/maildroppa/apis/maildroppa-api-beta/revisions/a9f5a3fd1fb0?raw)