> For the complete documentation index, see [llms.txt](https://docs.carbonmark.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.carbonmark.com/carbonmark-api.md).

# CARBONMARK API

- [Introduction to Carbonmark API](https://docs.carbonmark.com/carbonmark-api/readme.md): Discover carbon credit inventory, retrieve pricing, and retire credits programmatically.
- [Versioning & Release Process](https://docs.carbonmark.com/carbonmark-api/versioning-and-release-process.md): Learn how Carbonmark API versioning, deprecation, and upgrade timelines work so you can integrate against a stable version.
- [v19 (latest stable)](https://docs.carbonmark.com/carbonmark-api/versioning-and-release-process/v19-latest-stable.md)
- [v18 (deprecated)](https://docs.carbonmark.com/carbonmark-api/versioning-and-release-process/v18-deprecated.md)
- [v17 (retired)](https://docs.carbonmark.com/carbonmark-api/versioning-and-release-process/v17-retired.md)
- [v16 (retired)](https://docs.carbonmark.com/carbonmark-api/versioning-and-release-process/v16-retired.md)
- [v15 (retired)](https://docs.carbonmark.com/carbonmark-api/versioning-and-release-process/v15-retired.md)
- [Quickstart](https://docs.carbonmark.com/carbonmark-api/quickstart.md): Complete your first Carbonmark API integration by generating a sandbox key and submitting a test retirement.
- [Explore Carbon Projects](https://docs.carbonmark.com/carbonmark-api/explore-carbon-projects.md): Use the Carbonmark API to find carbon projects by country, vintage, methodology, or project details.
- [Find carbon projects by country](https://docs.carbonmark.com/carbonmark-api/explore-carbon-projects/find-carbon-projects-by-country.md): Use the Carbonmark API to retrieve available country values and return carbon projects that match a selected country.
- [Find carbon projects by vintage](https://docs.carbonmark.com/carbonmark-api/explore-carbon-projects/find-carbon-projects-by-vintage.md): Use the Carbonmark API to retrieve available vintages and return carbon projects that match a selected vintage.
- [Find carbon projects by methodology category](https://docs.carbonmark.com/carbonmark-api/explore-carbon-projects/find-carbon-projects-by-methodology-category.md): Use the Carbonmark API to retrieve available methodology categories and return carbon projects that match a selected category.
- [Find carbon projects by project name or description](https://docs.carbonmark.com/carbonmark-api/explore-carbon-projects/find-carbon-projects-by-project-name-or-description.md): Use the Carbonmark API to search carbon projects by project name or description using a text query.
- [Retire Carbon](https://docs.carbonmark.com/carbonmark-api/retire-carbon.md): Use the Carbonmark API to create retirement quotes, submit retirement orders, and confirm completion with a retirement receipt.
- [API Checkout Service](https://docs.carbonmark.com/carbonmark-api/api-checkout-service.md): Use the Checkout Service API to create hosted checkout links for carbon credit purchases and retirements, then track payment and retirement status through the API.