A JSON API is the widest source in our records. Sixty-three tools generate PDFs from data sent to an API, from small HTML converters to enterprise Word engines. The full list is on the JSON API to PDF page, and the JSON API hub covers the other outputs. This guide explains what each kind of API expects from you and how to narrow the field.
The native option
There is no native option, because the API is the generator. What matters is which kind of API you call, since the two kinds ask different work of you.
An HTML-to-PDF API expects finished HTML, or a URL, and returns a PDF. Your code does the templating. You merge the JSON into HTML with whatever library your stack already uses, add print CSS for page size, margins, headers and page breaks, and post the result. The API handles fonts, pagination and rendering. This suits teams that already build HTML views and want a PDF of them.
A template API expects a template stored with the provider and a JSON payload. You build the template once, in Word, HTML or a visual builder, with placeholders that name JSON fields. Each call sends the template ID and the data, and the provider fills the template and returns a PDF. Repeating data, such as invoice lines, goes in an array that the template loops over. This suits teams where someone outside engineering edits the layout.
Either way you will handle an API key, retries on failure, and storage of the file the API returns.
The Zapier, Make or n8n path
You do not have to write code to call these APIs. Many template APIs also offer steps in Zapier, Make or n8n, so a no-code workflow can send the JSON and nobody has to write integration code. Carbone, CraftMyPDF and APITemplate.io list all three platforms in our records. PDFMonkey lists Zapier and Make. The HTML-to-PDF converters in our records mostly list no automation integrations, which fits their developer focus.
Use this path when the data already moves through an automation platform, or when you want to test a template before anyone writes integration code.
Dedicated tools
Seven tools that show the range. Prices were checked on 20 Oct 2026.
- SourceToDocs takes JSON through its API, which comes with the Pro plan, writes Google Slides and Google Docs, and exports PDF, PPTX and DOCX from Google Docs templates. Plans start from $19 a month billed annually ($24 monthly), with a free plan of 1 document a month.
- Carbone is a template API that fills Word, Excel, PowerPoint, ODT or HTML templates, from about $28 a month (EUR 26, converted), with 100 free cloud documents a month and a free self-hosted Community edition.
- PDFMonkey is a template API with HTML and CSS templates, from about $5 a month (EUR 5) for 300 documents, with 20 free documents a month.
- CraftMyPDF is a template API with a drag-and-drop editor, from $29 a month for 1,200 PDFs, with 50 free PDFs a month.
- Anvil fills PDF forms and HTML templates and adds e-sign, metered at $0.10 a PDF after 2,500 free credits, with an AI Pack at $99 a month.
- DocRaptor is an HTML-to-PDF API built on the Prince engine, from $15 a month for 125 documents, with 5 free documents.
- Gotenberg is an MIT-licensed Docker API that converts HTML, Markdown and Office files to PDF through Chromium and LibreOffice, free to self-host.
Which route to pick
Pick by who edits the template. If developers own the layout and already render HTML, an HTML-to-PDF API is the shortest path. DocRaptor is hosted. Gotenberg runs on your own servers with no per-document fee, and you pay for the hosting and upkeep instead.
If someone in operations or design will change the layout, pick a template API. SourceToDocs suits people who work in Google Docs. Carbone suits people who work in Word. CraftMyPDF suits people who prefer a drag-and-drop editor. PDFMonkey suits people who can edit HTML and CSS.
Pick by volume next. Among these seven, free allowances run from 1 document a month with SourceToDocs to 2,500 credits with Anvil. The entry plans of PDFMonkey, DocRaptor, Carbone and CraftMyPDF run from about $5 to $29 a month and cover 125 to 1,200 documents on the plans that state a count. At tens of thousands, compare metered pricing such as Anvil’s per-PDF rate against flat plans, and price out self-hosting Gotenberg or Carbone Community.
Line items and long tables need a check of their own. With HTML you control page breaks in CSS. With a template API, confirm the template loops over arrays and repeats table headers across pages. Send your longest real payload during the trial.
If the document must be filled into an existing PDF form, for example a government form, look at tools with a PDF form editor, such as Anvil.
