> ## Documentation Index > Fetch the complete documentation index at: https://docs.spidra.io/llms.txt > Use this file to discover all available pages before exploring further. # Estimate a Monitor > Credits per check and per month for a monitor, before you create it. Takes the same body as [Create a Monitor](https://docs.spidra.io/api-reference/monitors/create.md), checks it the same way, and returns the cost. Free. ```bash theme={null} curl -X POST https://api.spidra.io/api/monitors/estimate \ -H "Authorization: Bearer $SPIDRA_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "sources": [{ "kind": "template", "template": "google-maps-leads", "inputs": { "query": "dentist", "areas": ["Lekki, Lagos"] } }], "schedule": { "every": "1h" }, "alertOn": "new" }' ``` ```json theme={null} { "status": "success", "creditsPerCheck": 1, "checksPerMonth": 720, "creditsPerMonth": 720, "usesAi": false } ``` The same source checked daily is 30 credits a month. `usesAi` is `true` when a source extracts with AI, which adds token credits on top. A `goal` adds a little AI only on checks where something changed, and isn't part of the estimate. ## OpenAPI ````yaml POST /monitors/estimate openapi: 3.1.0 info: title: Spidra API version: 1.0.0 description: >- Public API endpoints for web scraping via Spidra. Authenticate with `Authorization: Bearer YOUR_API_KEY`. servers: - url: https://api.spidra.io/api security: - BearerAuth: [] - ApiKeyAuth: [] paths: /monitors/estimate: post: tags: - Monitors summary: Estimate a Monitor description: >- Credits per check and per month for a monitor, before you create it. Takes the same body as [Create a Monitor](/api-reference/monitors/create). Free. requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/MonitorInput' example: name: Dentists in Lekki sources: - kind: template template: google-maps-leads inputs: query: dentist areas: - Lekki, Lagos schedule: every: 1d at: '08:00' timezone: Africa/Lagos alertOn: new notify: email: enabled: true responses: '200': description: The estimate. content: application/json: schema: type: object properties: status: type: string enum: - success creditsPerCheck: type: number checksPerMonth: type: integer creditsPerMonth: type: number usesAi: type: boolean description: >- true when a source extracts with AI, which adds token credits. '401': description: Missing or invalid API key. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' '422': description: Some inputs need fixing. `errors` lists each field. content: application/json: schema: $ref: '#/components/schemas/InvalidInputError' components: schemas: MonitorInput: type: object properties: name: type: string description: Defaults to the first source's label. sources: type: array items: $ref: '#/components/schemas/MonitorSource' minItems: 1 maxItems: 10 schedule: $ref: '#/components/schemas/MonitorSchedule' alertOn: type: string enum: - new - changed - removed - page - every description: >- What counts as a change. Default `page` when every source is a URL list, otherwise `new`. watchFields: type: array items: type: string maxItems: 20 description: 'alertOn changed: only these fields count. Empty means every field.' rule: $ref: '#/components/schemas/MonitorRule' goal: type: - string - 'null' maxLength: 1000 description: >- Plain-language goal. When something changed, AI decides whether it matches before alerting, and says why. notify: $ref: '#/components/schemas/MonitorNotify' checkNow: type: boolean default: true description: >- Create only: run the first check straight away. It records the starting point and doesn't alert. ErrorResponse: type: object properties: status: type: string enum: - error message: type: string required: - status - message InvalidInputError: type: object properties: status: type: string enum: - error code: type: string enum: - INVALID_INPUT message: type: string errors: type: array items: type: object properties: field: type: string message: type: string description: One entry per field that needs fixing. MonitorSource: type: object required: - kind properties: id: type: string description: >- Optional. Kept per source so changes are compared against the same source next time. kind: type: string enum: - template - preset - urls label: type: string description: Shown in alerts. Defaults to the template, preset or site name. template: type: string description: 'kind template: the template''s slug.' inputs: type: object description: 'kind template: the template''s inputs.' presetId: type: string description: >- kind preset: the preset's ID. Scrape, batch, map, search and template presets can be watched. urls: type: array items: type: string maxItems: 50 description: 'kind urls: up to 50 public pages.' MonitorSchedule: type: object properties: every: type: string enum: - 5m - 15m - 30m - 1h - 6h - 12h - 1d - 1w at: type: string description: >- "HH:MM". The time for 1d and 1w, and the minute past the hour for 1h, 6h and 12h. Default 09:00. day: type: integer minimum: 0 maximum: 6 description: '1w only: 0 is Sunday. Default 1 (Monday).' cron: type: string description: 'Instead of `every`: a 5-field cron expression.' timezone: type: string description: An IANA time zone such as Africa/Lagos. Default UTC. description: >- Your plan sets the shortest interval: daily on Free, hourly on Starter, every 15 minutes on Builder, every 5 minutes on Pro. MonitorRule: type: - object - 'null' properties: field: type: string op: type: string enum: - lt - lte - gt - gte - eq - neq - contains - drops_by_pct - rises_by_pct value: type: - number - string description: >- Only alert about items where this is true, for example `{ "field": "price", "op": "drops_by_pct", "value": 10 }`. MonitorNotify: type: object properties: email: type: object properties: enabled: type: boolean default: true recipients: type: array items: type: string maxItems: 10 description: >- Extra addresses. Each gets alerts only after confirming by email. description: Your account's email is on unless `enabled` is false. webhook: type: object properties: url: type: string description: A public https URL. secret: type: string description: >- 16 to 128 letters, digits, - or _. Generated when you leave it out. slack: type: object properties: webhookUrl: type: string description: A Slack incoming webhook URL (https://hooks.slack.com/...). discord: type: object properties: webhookUrl: type: string description: A Discord webhook URL (https://discord.com/api/webhooks/...). securitySchemes: BearerAuth: type: http scheme: bearer bearerFormat: API key ApiKeyAuth: type: apiKey in: header name: x-api-key ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.