---
title: "Create monitor"
method: POST
path: "/api/v1/monitors"
tags: ["Monitors"]
---

# Create monitor

`POST /api/v1/monitors`

Creates an account monitor. Monitors are unlimited. Active monitors check every 1 second and cost 21 credits per hour. Events and webhook deliveries are included. Creation requires available credits for the first hourly charge and username lookup.

## Request body

- object
  - `username` string, required — X username (without @)
  - `eventTypes` EventType[], required — Array of event types to subscribe to.

## Response `201`

Monitor created

- object
  - `id` string, required
  - `username` string, required
  - `xUserId` string, required
  - `eventTypes` EventType[], required — Array of event types to subscribe to.
  - `isActive` boolean, required
  - `createdAt` string, date-time, required
  - `nextBillingAt` string, date-time, required — Next hourly credit charge time. New active monitors are due immediately.

## Other responses

- `400` — Invalid input
- `401` — Unauthenticated
- `402` — Payment required. MPP reads include `WWW-Authenticate`. Authenticated reads include balances and checkout; a failed request never creates checkout. Guest keys offer top-up.
- `404` — X user not found
- `409` — Monitor already exists
- `429` — Xquik tier rate limit exceeded. The response includes a `Retry-After` header with the number of seconds to wait before retrying.
- `default` — Unexpected error.

## Changes

- **2026-08-21** `18302a60cfee` — 1 breaking, 1 info
  - the `oneOf[subschema #4]/allOf[subschema #2]/` response's property type/format changed from ``/`` to `object`/`` for status `402`
  - added 'propertyNames' constraint to the `oneOf[subschema #4]/allOf[subschema #2]/` response property for the status `402`
- **2026-08-12** `5d4938bb7de3` — 126 warning
  - added the new `closed` enum value to the `allOf[#/components/schemas/Error]/error/oneOf[subschema #1: LegacyErrorCode]/` response property for the response status `429`
  - added the new `closed` enum value to the `allOf[#/components/schemas/Error]/error/oneOf[subschema #2: StructuredError]/code` response property for the response status `429`
  - added the new `closed` enum value to the `error/oneOf[subschema #1: LegacyErrorCode]/` response property for the response status `400`
  - added the new `closed` enum value to the `error/oneOf[subschema #1: LegacyErrorCode]/` response property for the response status `401`
  - …122 more
- …earlier changes not shown

[Full history](https://skmtc.dev/xquik-dev/apis/xquik-api-2/changes/api/v1/monitors/post.md)

---

[API](https://skmtc.dev/xquik-dev/apis/xquik-api-2.md) · [All operations](https://skmtc.dev/xquik-dev/apis/xquik-api-2/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/xquik-dev/xquik-api-2/revisions/834c16fa45e8/schema)