> ## Documentation Index > Fetch the complete documentation index at: https://docs.sentivel.com/llms.txt > Use this file to discover all available pages before exploring further. # Create a monitor > Creates a monitor and its public component. `type` selects the kind: `http` (default, polls a URL), `heartbeat` (a scheduled job pings us; the response includes a `pingUrl` to wire into the job), or `tcp` (connects to a host:port). The first check runs on the next poll cycle (within ~2 minutes). ## OpenAPI ````yaml https://www.sentivel.com/api/v1/openapi.json post /monitors openapi: 3.1.0 info: title: Sentivel API version: 1.0.0 description: >- Provision and read your Sentivel workspace programmatically: components, monitors, status pages and incidents. Authenticate with an org API token (create one under Developers → API tokens in the dashboard). contact: name: Sentivel url: https://www.sentivel.com servers: - url: https://www.sentivel.com/api/v1 description: Production security: - bearerAuth: [] tags: - name: Identity description: Who the token is - name: Components description: Status-page components (status units) - name: Monitors description: Uptime/HTTP checks - name: Status pages description: Public status pages - name: Incidents description: Incidents (read + manual create) - name: People description: Workspace members - name: Integrations description: Outbound alert destinations - name: On-call description: On-call schedules paths: /monitors: post: tags: - Monitors summary: Create a monitor description: >- Creates a monitor and its public component. `type` selects the kind: `http` (default, polls a URL), `heartbeat` (a scheduled job pings us; the response includes a `pingUrl` to wire into the job), or `tcp` (connects to a host:port). The first check runs on the next poll cycle (within ~2 minutes). operationId: createMonitor parameters: - $ref: '#/components/parameters/IdempotencyKey' requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/MonitorCreate' responses: '201': description: The created monitor. content: application/json: schema: type: object properties: data: $ref: '#/components/schemas/Monitor' '400': description: >- Validation failed, or the target is not a public http(s) address/host. content: application/json: schema: $ref: '#/components/schemas/Error' '401': description: Unauthorized. content: application/json: schema: $ref: '#/components/schemas/Error' '403': description: The token's role can't manage monitors. content: application/json: schema: $ref: '#/components/schemas/Error' components: parameters: IdempotencyKey: name: Idempotency-Key in: header required: false description: >- Opt-in safe retries. Send a unique value (a UUID); a retry with the same key replays the first response (header `Idempotent-Replayed: true`) instead of acting twice. Reusing a key with a different body is rejected (400); a retry while the first is in flight gets 409. Scoped to the workspace, expires after 24h. schema: type: string maxLength: 255 schemas: MonitorCreate: description: >- Discriminated on `type`. Omit `type` for an HTTP monitor (backward-compatible). oneOf: - $ref: '#/components/schemas/HttpMonitorCreate' - $ref: '#/components/schemas/HeartbeatMonitorCreate' - $ref: '#/components/schemas/TcpMonitorCreate' discriminator: propertyName: type Monitor: type: object properties: id: type: string format: uuid name: type: - string - 'null' componentId: type: - string - 'null' format: uuid type: type: string enum: - http - heartbeat - tcp - dns target: type: string method: type: string intervalSeconds: type: integer timeoutMs: type: integer openThreshold: type: integer resolveThreshold: type: integer environment: type: - string - 'null' enabled: type: boolean lastCheckedAt: type: - string - 'null' format: date-time createdAt: type: string format: date-time pingUrl: type: string format: uri description: >- Heartbeat only, returned on create. The URL the scheduled job pings. It's a secret credential, so it is not returned by the list/get endpoints. Error: type: object properties: error: type: object properties: code: type: string enum: - unauthorized - forbidden - not_found - invalid_request - rate_limited - conflict - internal message: type: string details: type: object required: - code - message HttpMonitorCreate: type: object required: - name - target properties: type: type: string enum: - http default: http name: type: string minLength: 1 maxLength: 120 target: type: string format: uri description: The URL to poll. http/https only; SSRF-validated. method: type: string enum: - GET - HEAD - POST intervalSeconds: type: integer minimum: 60 maximum: 86400 description: Poll cadence (60s floor). timeoutMs: type: integer minimum: 1000 maximum: 60000 openThreshold: type: integer minimum: 1 maximum: 10 resolveThreshold: type: integer minimum: 1 maximum: 10 expectedStatusCodes: type: array items: type: integer minimum: 100 maximum: 599 description: Healthy status codes. Empty/absent = any 2xx–3xx. keyword: type: string maxLength: 200 keywordAbsent: type: string maxLength: 200 jsonAssertion: type: object description: >- Assert on a JSON response: navigate `path` (dot/bracket, leading $. optional) and compare with `op`. required: - path - op properties: path: type: string maxLength: 200 op: type: string enum: - eq - ne - contains - gt - lt - exists value: type: string maxLength: 500 degradedAfterMs: type: integer minimum: 1 maximum: 60000 description: A passing check slower than this is reported degraded (still up). latencyThresholdMs: type: integer minimum: 1 maximum: 60000 description: >- A check slower than this FAILS (opens an incident after the flap threshold). headers: type: object additionalProperties: type: string description: >- Custom request headers (e.g. Authorization). Stored encrypted; sent only to the original host (dropped on a cross-host redirect). body: type: string maxLength: 32768 description: >- Request body for a POST/PUT check. Stored encrypted (may carry secrets). contentType: type: string maxLength: 200 description: Content-Type for `body` (default application/json). environment: type: - string - 'null' maxLength: 60 metadata: type: object additionalProperties: type: string HeartbeatMonitorCreate: type: object required: - type - name - intervalSeconds description: >- A dead-man's-switch: no outbound poll. The scheduled job pings the returned `pingUrl`; we alarm when a ping is overdue. properties: type: type: string enum: - heartbeat name: type: string minLength: 1 maxLength: 120 intervalSeconds: type: integer minimum: 60 maximum: 2592000 description: Expected period between pings (up to 30 days). graceSeconds: type: integer minimum: 0 maximum: 86400 description: Slack beyond the interval before a missing ping is a miss. environment: type: - string - 'null' maxLength: 60 TcpMonitorCreate: type: object required: - type - name - host - port description: Opens a TCP socket to host:port on a cadence. properties: type: type: string enum: - tcp name: type: string minLength: 1 maxLength: 120 host: type: string minLength: 1 maxLength: 255 description: Public host (not localhost or a private IP). port: type: integer minimum: 1 maximum: 65535 intervalSeconds: type: integer minimum: 60 maximum: 86400 timeoutMs: type: integer minimum: 1000 maximum: 60000 openThreshold: type: integer minimum: 1 maximum: 10 resolveThreshold: type: integer minimum: 1 maximum: 10 environment: type: - string - 'null' maxLength: 60 securitySchemes: bearerAuth: type: http scheme: bearer description: 'An org API token (`sv_…`), sent as `Authorization: Bearer `.' ````