> ## Documentation Index > Fetch the complete documentation index at: https://iotools.cloud/docs/llms.txt > Use this file to discover all available pages before exploring further. # Get tool schema > Input and output JSON Schema for one tool, plus what a run costs your key. Use it after `search` to learn a tool's exact contract without pulling the full catalog. Free: this call costs no credits. ## OpenAPI ````yaml https://api.iotools.cloud/v1/openapi get /v1/tool/{slug} openapi: 3.1.0 info: title: iotools.cloud API version: 1.0.0 description: >- Run any iotools.cloud tool over HTTP. Authenticate with `Authorization: Bearer iot_live_…`. **Only `POST /v1/tool/{slug}` costs credits.** Every GET here — the catalog, a tool's schema, your balance — is free. A tool call is charged its own weight or your plan's per-call minimum, whichever is larger; `x-iotools-credit-cost` on each operation is quoted at the free-tier minimum, and `GET /v1/tools/list` returns the exact figure for your key. `GET /v1/me/credits` reports what you have left, and `GET /v1/me/usage` reports what it went on. Failures are RFC 9457 problem documents — branch on `code`. servers: - url: https://api.iotools.cloud description: Production security: - bearerAuth: [] tags: - name: Catalog description: Find a tool and read its contract. Free. - name: Converters description: >- Convert between formats, encodings, and units — Base64, CSV and JSON, timestamps, and more. Fast, free, and processed right in your browser. - name: Formatters description: >- Format, beautify, minify, and validate code and data — JSON, HTML, CSS, SQL, and regex. Clean up messy input in one click, with nothing to upload. - name: Generators description: >- Generate exactly what you need and on demand — passwords, UUIDs, QR codes, hashes, random numbers, and more. Secure, instant, and free. - name: Calculators description: >- Crunch the numbers fast — from everyday math to specialized conversions and unit work. Free online calculators that run entirely in your browser. - name: Editors description: >- Edit and transform text, code, and images with quick, focused editors that run entirely in your browser — nothing to install, and no sign-up needed. - name: Utilities description: >- Everyday developer and web utilities — DNS and IP lookups, redirect and certificate checkers, and other quick diagnostics. Free and privacy-friendly. - name: Account description: Your key's allowance, limits and usage history. paths: /v1/tool/{slug}: get: tags: - Catalog summary: Get tool schema description: >- Input and output JSON Schema for one tool, plus what a run costs your key. Use it after `search` to learn a tool's exact contract without pulling the full catalog. Free: this call costs no credits. operationId: get_tool_schema parameters: - name: slug in: path required: true schema: type: string description: 'The tool''s slug. Nested slugs keep their slash: `ai-writer/story`.' example: case-converter responses: '200': description: The tool's contract. content: application/json: schema: type: object properties: slug: type: string title: type: string description: type: string category: type: string credit_cost: type: integer description: >- Credits a run of this tool costs YOUR key, floor included — so it already reflects your plan and can be compared directly against `GET /v1/me/credits`. credit_cost_multiplier_field: type: string description: >- Present only on per-unit tools: `credit_cost` is then a rate, and a run costs it times the value of this input field. schema: type: object required: - input - output properties: input: type: object description: JSON Schema for the tool's inputs. output: type: object description: JSON Schema for the tool's outputs. '401': description: Missing or invalid API key. content: application/problem+json: schema: $ref: '#/components/schemas/Problem' example: type: https://iotools.cloud/docs/errors/invalid_api_key title: Invalid API key status: 401 code: invalid_api_key detail: 'Provide ''Authorization: Bearer ''.' request_id: e4042b29-8f1e-4c7a-9b52-6f0d1a3c7e11 '403': description: Tool exists but has no API surface. content: application/problem+json: schema: $ref: '#/components/schemas/Problem' example: type: https://iotools.cloud/docs/errors/tool_not_allowed title: Tool not available over the API status: 403 code: tool_not_allowed detail: >- "Background Remover" is available on iotools.cloud but has no API endpoint. request_id: e4042b29-8f1e-4c7a-9b52-6f0d1a3c7e11 '404': description: No such tool. content: application/problem+json: schema: $ref: '#/components/schemas/Problem' example: type: https://iotools.cloud/docs/errors/tool_not_found title: Tool not found status: 404 code: tool_not_found detail: No tool with the slug "no-such-tool". request_id: e4042b29-8f1e-4c7a-9b52-6f0d1a3c7e11 '429': description: Rate limited. content: application/problem+json: schema: $ref: '#/components/schemas/Problem' example: type: https://iotools.cloud/docs/errors/rate_limited title: Rate limit exceeded status: 429 code: rate_limited detail: Too many requests. Retry in 30s. request_id: e4042b29-8f1e-4c7a-9b52-6f0d1a3c7e11 security: - bearerAuth: [] components: schemas: Problem: type: object description: >- RFC 9457 problem document, served as application/problem+json. Branch on `code`; `title` is human prose and may be reworded without notice. required: - type - title - status - code properties: type: type: string format: uri description: Stable documentation URI for this failure. examples: - https://iotools.cloud/docs/errors/invalid_api_key - https://iotools.cloud/docs/errors/api_unconfigured - https://iotools.cloud/docs/errors/validation_error - https://iotools.cloud/docs/errors/payload_too_large - https://iotools.cloud/docs/errors/tool_not_found - https://iotools.cloud/docs/errors/tool_not_allowed - https://iotools.cloud/docs/errors/tool_disabled - https://iotools.cloud/docs/errors/rate_limited - https://iotools.cloud/docs/errors/insufficient_credits - https://iotools.cloud/docs/errors/processing_error - https://iotools.cloud/docs/errors/internal_error title: type: string examples: - Invalid API key - API not configured - Invalid request - Payload too large - Tool not found - Tool not available over the API - Tool temporarily disabled - Rate limit exceeded - Insufficient credits - Tool failed to run - Internal error status: type: integer code: type: string enum: - invalid_api_key - api_unconfigured - validation_error - payload_too_large - tool_not_found - tool_not_allowed - tool_disabled - rate_limited - insufficient_credits - processing_error - internal_error detail: type: string description: Human explanation of this occurrence. request_id: type: string description: Correlation id, also sent as x-request-id. securitySchemes: bearerAuth: type: http scheme: bearer bearerFormat: iot_live_… ````