# Callable Labs

> APIs for documents, images, codes, calendars, currency and speech. Production credentials, plans and billing come from available RapidAPI and ApyHub capability listings. Website demos use separate credentials and bounded anonymous allowances.

## Start here
- [Getting started](https://www.callablelabs.com/getting-started): authentication, subscriptions and troubleshooting.
- [API access](https://www.callablelabs.com/api-access): capability availability and billing units.
- [Playground](https://www.callablelabs.com/playground): all 53 documented operations, guided fields, reference lookups and editable JSON; examples remain available when live execution is paused.
- [OpenAPI](https://www.callablelabs.com/openapi): reviewed public schemas and Postman templates.

## APIs
- [QR & Barcode API](https://www.callablelabs.com/apis/qr-code-api): Generate QR codes and barcodes, read symbols from images, and validate structured payment payloads.
  - [Quickstart](https://www.callablelabs.com/docs/qr-code-api/quickstart)
  - [Reference](https://www.callablelabs.com/docs/qr-code-api/reference)
  - [OpenAPI JSON](https://www.callablelabs.com/openapi/qr.json)
  - [Task tutorial](https://www.callablelabs.com/tutorials/generate-qr-code-python)
- [Document Generation API](https://www.callablelabs.com/apis/document-generation-api): Turn JSON, Word templates, HTML and Markdown into finished PDF and DOCX documents.
  - [Quickstart](https://www.callablelabs.com/docs/document-generation-api/quickstart)
  - [Reference](https://www.callablelabs.com/docs/document-generation-api/reference)
  - [OpenAPI JSON](https://www.callablelabs.com/openapi/documents.json)
  - [Task tutorial](https://www.callablelabs.com/tutorials/generate-invoice-pdf-json)
- [OCR & PDF to Markdown API](https://www.callablelabs.com/apis/pdf-to-markdown-api): Read images and PDF pages into text, Markdown, tables and structured document blocks.
  - [Quickstart](https://www.callablelabs.com/docs/pdf-to-markdown-api/quickstart)
  - [Reference](https://www.callablelabs.com/docs/pdf-to-markdown-api/reference)
  - [OpenAPI JSON](https://www.callablelabs.com/openapi/ocr.json)
  - [Task tutorial](https://www.callablelabs.com/tutorials/pdf-to-markdown-python)
- [Diagram, Math & Code Render API](https://www.callablelabs.com/apis/diagram-rendering-api): Render Mermaid, Graphviz, D2, Vega-Lite, LaTeX and source code as shareable images and PDFs.
  - [Quickstart](https://www.callablelabs.com/docs/diagram-rendering-api/quickstart)
  - [Reference](https://www.callablelabs.com/docs/diagram-rendering-api/reference)
  - [OpenAPI JSON](https://www.callablelabs.com/openapi/render.json)
  - [Task tutorial](https://www.callablelabs.com/tutorials/render-mermaid-diagram-api)
- [Background Removal API](https://www.callablelabs.com/apis/background-removal-api): Separate a subject from its background, export a transparent cutout or create an alpha mask.
  - [Quickstart](https://www.callablelabs.com/docs/background-removal-api/quickstart)
  - [Reference](https://www.callablelabs.com/docs/background-removal-api/reference)
  - [OpenAPI JSON](https://www.callablelabs.com/openapi/background.json)
  - [Task tutorial](https://www.callablelabs.com/tutorials/remove-background-product-photo)
- [Holidays & Business Days API](https://www.callablelabs.com/apis/country-holidays-api): Look up country holidays, regional calendars, market closures and business-day calculations.
  - [Quickstart](https://www.callablelabs.com/docs/country-holidays-api/quickstart)
  - [Reference](https://www.callablelabs.com/docs/country-holidays-api/reference)
  - [OpenAPI JSON](https://www.callablelabs.com/openapi/holidays.json)
  - [Task tutorial](https://www.callablelabs.com/tutorials/country-holidays-python)
- [Exchange Rates API](https://www.callablelabs.com/apis/currency-exchange-api): Convert currencies using daily ECB reference rates, historical publications and official fixed parities.
  - [Quickstart](https://www.callablelabs.com/docs/currency-exchange-api/quickstart)
  - [Reference](https://www.callablelabs.com/docs/currency-exchange-api/reference)
  - [OpenAPI JSON](https://www.callablelabs.com/openapi/fx.json)
  - [Task tutorial](https://www.callablelabs.com/tutorials/convert-currency-python)
- [Speech-to-Text & Subtitles API](https://www.callablelabs.com/apis/speech-to-text-api): Transcribe audio in 25 European languages and export text, word timings or SRT and WebVTT subtitles.
  - [Quickstart](https://www.callablelabs.com/docs/speech-to-text-api/quickstart)
  - [Reference](https://www.callablelabs.com/docs/speech-to-text-api/reference)
  - [OpenAPI JSON](https://www.callablelabs.com/openapi/speech.json)
  - [Task tutorial](https://www.callablelabs.com/tutorials/transcribe-audio-subtitles-python)

## Integration notes
Use the exact listing host, public route and authentication for the selected capability. Availability varies by operation. Keep keys on the server; never enter a marketplace key into the website. Validate response content, not just status. Larger workloads belong on the marketplace APIs.