# thirds.ai REST API

**Canonical:** https://apis.io/apis/thirds-ai/thirdsai-rest-api/  
**Provider:** thirds.ai — https://apis.io/providers/thirds-ai/  
**Base URL:** https://thirds.ai/v1  
**Documentation:** https://thirds.ai/docs/api-reference

thirds.ai REST API is one of 2 APIs that [thirds.ai](https://apis.io/providers/thirds-ai/) publishes on the [APIs.io](https://apis.io/) network, described by a machine-readable OpenAPI specification. Tagged areas include pdf-automation, image-automation, Document Generation, HTML to PDF, and HTML to Image. The published artifact set on APIs.io includes an OpenAPI specification, API documentation, an API reference, and a getting-started guide.

REST API for HTML-to-PDF, HTML-to-image, AI template generation, template editing, brand kits, rendering, and batch operations. Bearer API key auth with idempotency support.

## Operations (60 of 69)

| Method | Path | Summary |
|---|---|---|
| POST | `/v1/webhooks/{webhook_id}/test` | Send a signed test event |
| GET | `/v1/webhooks/{webhook_id}/deliveries` | Read recent webhook attempts |
| POST | `/v1/me/identities/email` | Add an email to an account without one |
| POST | `/v1/image-assets/preview` | Preview a URL image |
| POST | `/v1/image-assets` | Upload an image |
| GET | `/v1/image-assets/{id}/content` | Read an owned image |
| GET | `/v1/openapi.json` | Get the OpenAPI document |
| GET | `/v1/public-stats` | Read measured public facts |
| POST | `/v1/testimonials` | Offer a testimonial for private review |
| POST | `/v1/pdf` | Create a PDF |
| GET | `/v1/pdf` | List render history |
| POST | `/v1/image` | Create a static image |
| GET | `/v1/image` | List image history |
| GET | `/v1/image/{id}` | Get a static image's status |
| DELETE | `/v1/image/{id}` | Delete an image file or an unsuccessful render |
| POST | `/v1/image-packs` | Create an image pack |
| GET | `/v1/image-packs/{id}` | Get an image pack's status |
| POST | `/v1/image-packs/{id}/retry` | Retry an image pack's failed members |
| POST | `/v1/carousels` | Create a carousel |
| GET | `/v1/carousels/{id}` | Get a carousel's status |
| POST | `/v1/carousels/{id}/retry` | Retry a carousel's failed members |
| POST | `/v1/batches` | Create a render batch |
| GET | `/v1/batches/{id}` | Get a render batch's status |
| POST | `/v1/batches/{id}/retry` | Retry a batch's failed, cancelled, or pending rows |
| POST | `/v1/batches/{id}/cancel` | Cancel a batch's pending and queued rows |
| POST | `/v1/template-builds` | Start a template build |
| GET | `/v1/template-builds/{build_id}` | Get a template build |
| GET | `/v1/template-builds/{build_id}/messages` | List template chat messages |
| POST | `/v1/template-builds/{build_id}/messages` | Edit the working template |
| GET | `/v1/template-builds/{build_id}/draft` | Get the working template |
| GET | `/v1/template-builds/{build_id}/messages/{message_id}/draft` | Get a completed message draft |
| DELETE | `/v1/template-builds/{build_id}/messages/{message_id}` | Cancel a pending template message |
| POST | `/v1/template-builds/{build_id}/publish` | Publish the current working template |
| POST | `/v1/templates` | Create a saved template |
| GET | `/v1/templates` | List saved templates |
| POST | `/v1/templates/preview` | Preview template data as HTML |
| POST | `/v1/templates/adapt` | Adapt one HTML source to many canvas sizes |
| GET | `/v1/templates/{template_id}` | Get a saved template |
| PATCH | `/v1/templates/{template_id}` | Rename a saved template |
| DELETE | `/v1/templates/{template_id}` | Archive a saved template |
| POST | `/v1/templates/{template_id}/versions` | Create a template version |
| GET | `/v1/templates/{template_id}/versions` | List template versions |
| GET | `/v1/templates/{template_id}/versions/{version}` | Get a template version |
| POST | `/v1/brand-kits` | Create a brand kit |
| GET | `/v1/brand-kits` | List brand kits |
| GET | `/v1/brand-kits/{brand_kit_id}` | Get a brand kit |
| PATCH | `/v1/brand-kits/{brand_kit_id}` | Update a brand kit |
| DELETE | `/v1/brand-kits/{brand_kit_id}` | Archive a brand kit |
| POST | `/v1/brand-kits/{brand_kit_id}/assets` | Add a brand asset |
| GET | `/v1/brand-kits/{brand_kit_id}/assets/{asset_id}` | Read a brand asset |
| PUT | `/v1/brand-kits/{brand_kit_id}/assets/{asset_id}` | Replace a brand asset |
| GET | `/v1/pdf/{id}` | Get a PDF's status |
| DELETE | `/v1/pdf/{id}` | Delete a PDF file or an unsuccessful render |
| GET | `/v1/downloads/{token}` | Download a finished PDF or image |
| GET | `/v1/image-packs/archive/{token}` | Download an image pack's ZIP archive |
| GET | `/v1/carousels/archive/{token}` | Download a carousel's ZIP archive |
| GET | `/v1/batches/archive/{token}` | Download a batch's ZIP archive |
| POST | `/v1/keys` | Create an API key |
| GET | `/v1/keys` | List API keys |
| DELETE | `/v1/keys/{key_id}` | Revoke an API key |

…and 9 more operations. They are listed in full on the page.

## Machine-readable artifacts (8)

- **OpenAPI** — https://raw.githubusercontent.com/api-evangelist/thirds-ai/refs/heads/main/openapi/thirds-ai-openapi.yml
- **OpenAPI** — https://thirds.ai/v1/openapi.json
- **Documentation** — https://thirds.ai/docs
- **LLMsTxt** — https://thirds.ai/llms.txt
- **Overlay** — https://raw.githubusercontent.com/api-evangelist/thirds-ai/refs/heads/main/overlays/thirds-ai-openapi-overlay.yaml
- **APIReference** — https://thirds.ai/docs/api-reference
- **GettingStarted** — https://thirds.ai/docs/quickstart
- **APIsJSON** — https://raw.githubusercontent.com/api-evangelist/thirds-ai/refs/heads/main/apis.yml

## Other thirds.ai APIs (1)

- [thirds.ai MCP Server](https://apis.io/apis/thirds-ai/thirdsai-mcp-server/)

## Tags

pdf-automation, image-automation, Document Generation, HTML to PDF, HTML to Image, template-rendering, Branded Content, Developer Tools, MCP Server, agent-native, marketing-ops

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/thirds-ai/thirdsai-rest-api/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/thirds-ai/.