thirds.ai
Start free
Menu

thirds.ai docs for making PDFs and images

Save a design once, then fill it with new details in the editor, from your code, or with your AI tool. You get back a finished PDF or image, and each one costs one credit.

Make a sample imageAPI reference
POST /v1/pdf
curl https://thirds.ai/v1/pdf \
  -H "Authorization: Bearer $THIRDS_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: completion-certificate-1" \
  -d '{
    "template_id": "tpl_your_copy",
    "version": 1,
    "data": {
      "issuer": "Chalkline Learning",
      "learner": "Alexandra Morgan",
      "course": "Clear Project Plans for Small Teams",
      "date": "14 September 2026"
    }
  }'

Send these fields with your API key, and you get this certificate back as a PDF with a signed download link.

A portrait certificate of completion with a dark green engraved band, gold foil title, and the learner's name centred on cream paper.
Portrait course certificate

Guides

Find the guide for your task

Pick the task you want to do. Each guide takes you from the first step to the finished file.

Start here

Get an API key and make your first PDF.

2 guides

Create and reuse

Design a template, fill it with your data, and set the output.

5 guides

Connect your app

Work from your agent, hear when a file is ready, and recover a failed request.

3 guides

Workflow apps

Fill a saved design from Zapier, Make, or n8n.

3 guides

Recipes

Follow a worked example for a common integration.

3 guides

API reference

Look up each endpoint with its fields and responses.

15 guides

MCP clients

Connect the client you already use.

19 guides

Reference

Look up error codes, limits, short answers, and billing.

4 guides

Migrations

Move from another tool with a field-by-field map.

1 guide

Three ways in

Work in the browser, from your code, or with your AI agent

Every path uses the same saved templates, credits, and files, so you can start in the browser and automate later without rebuilding anything.

The thirds.ai editor with boxes for the month, the business name, and the revenue beside the finished Harrow & Vale Architecture monthly report

Work in the browser without code

Open a design such as the Monthly report, type your details in the Data tab, and click Export. Your code or your agent can then fill the same saved design with new data.

Make a template you can reuse
Response, shortened
{
  "id": "pdf_1f8b3c7d5e2a49061f8b3c7d5e2a4906",
  "status": "succeeded",
  "download": {
    "url": "/v1/downloads/…",
    "expires_at": "2026-10-17T09:00:00Z"
  }
}

Send a request from your code

Send a JSON body with your API key and an idempotency key for each file. You get the job's status back, and a signed download link once the file is ready.

API keys and requests
Use with your agent

Give this prompt to your AI agent. The agent does the task for you.

Read https://thirds.ai/docs and help me choose how to create PDFs or images with thirds.ai and walk me through the first steps.

Ask your AI agent to do it

Connect the MCP server to Claude Code, Cursor, ChatGPT, or another client, and your agent creates templates and files for you with your credits.

Connect your AI agent

Ready to make your first file?

Start in the playground with a gallery template, or follow the quickstart and send your first request from your own terminal.

Make a sample imageGenerate your first PDF