thirds.ai and PDFShift
PDFShift is an API that turns HTML or a web page into a PDF or a screenshot image. thirds.ai turns words, your own HTML, or a source image into an editable branded template, then renders that template as a PDF or a static image through the web app, the API, or MCP. This page helps you choose between the two when you need documents or images from HTML, and it helps you plan a move if you already use PDFShift. thirds.ai is not affiliated with PDFShift, and PDFShift is a trademark of its owner.
Checked on 6 September 2026 against the sources listed at the end.
The short answer
If you only need a fast API that turns finished HTML or a public web page into a PDF, PDFShift is a good fit with a large set of conversion options, and it fits well when your app already builds the HTML itself. thirds.ai fits better when you want to keep one editable template that your team can change in a visual editor or an AI chat, keep it on brand with a brand kit, and render both PDFs and images from it with the same credit price. Both tools give you an API and a free monthly allowance, so you can try each one with your own document before you decide.
Side by side
| What you need | thirds.ai | PDFShift |
|---|---|---|
| Inputs | Words in an AI chat, your own HTML with template data, or a source image that becomes an editable template. The API takes HTML text, not a page URL. | HTML text or a URL in the source field. PDFShift loads the URL for you (vendor claim). |
| Outputs | PDF, PNG, JPEG, and WebP. | PDF, PNG, JPEG, and WebP (vendor claim). No video on either side. |
| Template editing | A visual editor and an AI chat that share one working template, with immutable saved versions. | Stored HTML templates that you fill with data through the API (vendor claim). We saw no visual editor on the site (our reading). |
| Brand kits | Saved logos, colours, and fonts that the editor and the AI apply to each template. | Not shown on the pages we read (our reading). |
| API and MCP | A REST API at /v1/pdf, /v1/image, and /v1/templates, plus an MCP server for AI agents. | A REST API at https://api.pdfshift.io/v3 with POST /convert/pdf and POST /convert/png, a sandbox flag, S3 export, and webhooks (vendor claim). We found no MCP server (our reading). |
| Pricing model | One credit per successful PDF or image. Starter is $29 a month for 5,000 credits. Extra credits cost $0.008 each on a paid plan. | One credit per document, counted per 5 MB of output, so a 14 MB PDF costs 3 credits (vendor claim, seen 6 September 2026). Starter is $9 a month for 500 credits, with overage at $0.04. |
| Free tier | 25 credits a month with a verified account, no card needed, and every feature included. | 50 credits a month, no card needed, with a 15 MB file limit and a 30 second timeout (vendor claim, seen 6 September 2026). |
| Where it fits | Teams that want one editable branded template for both documents and images, with a web app and an API on the same account (our reading). | Developers who already have finished HTML or a public page and want a pure conversion API with many options (our reading). |
What thirds.ai does not do
- It does not load a page URL as the input. Your app sends the HTML text.
- It does not offer PDF password protection, watermark options, or direct export to your own S3 bucket.
- It does not offer a sandbox flag. Failed renders cost nothing, and 25 free credits reset each month.
- It does not have Zapier or Make integrations.
What PDFShift does not do
- It does not offer a visual editor, an AI chat, or a source-image import on the pages we read (our reading).
- It does not show brand kits or an MCP server on the pages we read (our reading).
- It does not roll unused credits into the next month (vendor claim).
- It counts a large output as more than one credit, so file size changes the price (vendor claim).
Pricing assumptions
- We read both pricing pages on 6 September 2026. Prices can change, so check the PDFShift pricing page and our pricing page before you decide.
- One thirds.ai credit is one successful PDF of up to 100 pages or one successful image. Failed renders cost nothing. See credits and billing.
- One PDFShift credit is one document per 5 MB of generated data (vendor claim). We did not test how PDFShift counts image conversions.
- We compare the monthly price of each entry paid plan. Both vendors offer a yearly price with a discount.
- Both free tiers reset each month and need no card. PDFShift gives 50 credits and thirds.ai gives 25 credits. thirds.ai includes every feature on the free plan.
Moving from PDFShift
Both APIs take HTML text and a small options object, so most of the move is a field rename. PDFShift puts the document in source and the page options at the top level, such as format, landscape, and margin. thirds.ai puts the document in html and the page options in a pdf object, such as pdf.format, pdf.landscape, and pdf.margins. PDFShift returns the file in the response body by default, while thirds.ai creates a render job and gives you a download link when the job succeeds.
Follow the pattern in our wkhtmltopdf migration guide: save sample inputs and PDFs, move one document type, compare the output, then move the next. Start with Create your first PDF, then set page options with the PDF and image options guide. If you load a URL in PDFShift today, fetch that HTML in your app first and send the text.
Sources
- https://pdfshift.io/, checked 6 September 2026
- https://pdfshift.io/pricing, checked 6 September 2026
- https://docs.pdfshift.io/, checked 6 September 2026
- https://docs.pdfshift.io/api-reference/convert-to-pdf, checked 6 September 2026
- https://docs.pdfshift.io/api-reference/convert-to-png, checked 6 September 2026
- https://docs.pdfshift.io/docs/webhook-events, checked 6 September 2026
- https://docs.pdfshift.io/api-reference/templates/generate-document-from-template, checked 6 September 2026
- thirds.ai facts come from our pricing page, API reference, and billing guide.
Try your own HTML on both tools before you choose. Start free with 25 credits a month, or read how HTML to PDF works on thirds.ai.