PDFops.dev
PDF.co
Anvil PDF Filling API
DocSpring
DocRaptor
Doczilla
wkhtmltopdf
PDF Generator API
DocuSign
MailMergic
HTML PDF API
PDFops is a hosted PDF API built for edge runtimes (Cloudflare Workers, Vercel Edge, Deno, Bun). Two endpoints, one HTTP call each:
What's different from cloud PDF platforms: no headless browser, no native binaries, and deterministic, byte-identical output for the same input โ so you can hash, cache, diff, and sign the result. It's callable directly from an edge function: POST a template plus data, get bytes back.
Built for developers and AI apps that need to write PDFs programmatically without operating a rendering service. Free tier: 100 requests/month per IP, no signup. Pro: $16 for 4,000 calls ($0.004/call) โ about 25ร cheaper per call than incumbent hosted APIs.
Also free, no signup: a PDF field Inspector (paste a PDF, see its AcroForm fields) and a live playground.
We provide a PDF filling and generation API:
PDF generation doesn't need to be complicated or take weeks of engineering time. Use our battle-tested service to start filling out PDFs in minutes.
PDFops.dev DocSpringPDFops.dev's answer
TypeScript on the Hono web framework, with a pure-JavaScript PDF engine (a maintained pdf-lib fork) and no native dependencies. That combination runs inside V8 isolates, which is what lets PDFops execute on edge runtimes such as Cloudflare Workers and Vercel Edge.
DocSpring's answer:
Ruby on Rails, React, AWS
PDFops.dev's answer
Deterministic, byte-identical PDF output from a single HTTP call โ and it runs from edge runtimes (Cloudflare Workers, Vercel Edge, Deno, Bun) with no headless browser and no native dependencies. The same input always yields the same bytes, so you can hash, cache, diff, and sign the result.
DocSpring's answer:
DocSpring is built specifically for developers who need reliable, secure PDF generation in production. We combine PDF form filling and HTML-to-PDF in a single API, with a visual template editor, typed fields, and validation to catch issues early. Our product has a lot of power features and is built to handle very advanced forms. Our infrastructure is SOC 2 Type II compliant, battle-tested, privacy focused, and optimized for high-volume workloads, so you can ship PDF features quickly and then stop thinking about them.
PDFops.dev's answer
No per-call tax: $0.004 per call versus the ~$0.10 typical of incumbent hosted PDF APIs (~25ร cheaper). It runs at the edge instead of round-tripping to a vendor cloud, the output is deterministic (hashable and cacheable), and there is a free, no-signup tier plus a PDF field Inspector for exploring a documentโs AcroForm fields before writing any code.
DocSpring's answer:
DocSpring is designed for teams who need a powerful tool with all the features you need for complex forms and business logic. DocSpring supports structured JSON, typed fields, and array iterations, and many other advanced features, so your templates stay aligned with your real data model. You get powerful validation, a visual editor, strong observability, and an API that fits into modern engineering workflows, so you spend less time fighting PDFs and more time shipping product.
PDFops.dev's answer
Developers and AI-application builders who need to fill AcroForm fields or merge PDFs programmatically โ especially teams deploying on edge runtimes who cannot run a headless browser or native PDF binaries inside a V8 isolate.
DocSpring's answer:
DocSpring is built for engineering and product teams who manage complex documents in production: things like financial applications, insurance forms, healthcare and legal documents, HR and payroll workflows, and government-style forms.
PDFops.dev's answer
PDFops started from a recurring edge-runtime pain: nearly every PDF API assumes a server with a headless browser or native libraries, which you cannot run inside a V8 isolate like Cloudflare Workers or Vercel Edge. PDFops is the deterministic write-and-merge primitive built for that environment โ one HTTP call, predictable bytes out.
DocSpring's answer:
I used to work at a payroll company (Gusto). We had built a similar in-house tool for filling out tax forms. I then built the first version of DocSpring (formerly named FormAPI) while I was living in Thailand. I built it to automate the filling out of visa application and visa extension forms, but realized that it could also be used for tax forms, real estate contracts, and any other kind of fillable PDF form.
DocSpring's answer:
Based on our record, DocSpring should be more popular than PDFops.dev. It has been mentiond 5 times since March 2021. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
// src/index.ts โ Cloudflare Worker (module syntax) Export interface Env { TEMPLATES: R2Bucket; // bucket holding your blank AcroForm PDFs } Export default { async fetch(req: Request, env: Env): Promise { if (req.method !== 'POST') { return new Response('POST a JSON body of field values', { status: 405 }); } // 1. The values to write into the form's named fields. const... - Source: dev.to / 3 days ago
I'm still working on DocSpring [1], originally launched on Hacker News in October 2017 under the name "FormAPI." It's a PDF generation API with a template editor UI for setting up fields on PDF forms. It makes it easy to turn complex tax and immigration forms into simple type-safe APIs with strong validations. I've been having a lot of fun with AI agents lately. Have tried a lot of them - Cline, Roo Code,... - Source: Hacker News / over 1 year ago
For programmatic filling of PDFs, have a look at DocSpring: https://docspring.com. - Source: Hacker News / over 2 years ago
Great post. I've spend a lot of time reading through the PDF specification over the last ~5 years while building DocSpring [1], and I still feel like I've barely scratched the surface. Qpdf is a great tool. One of my other favorites is RUPS [2], which really lets you dig into the structure of a PDF. [1] https://docspring.com [2] https://github.com/itext/i7j-rups. - Source: Hacker News / almost 3 years ago
Hi /u/pepeday, Iโm the founder of a software product that I built to solve this problem. The service is called DocSpring: https://docspring.com We provide a platform that you can use to set up PDF templates, and automatically generate PDFs by filling in those templates with data from your database. Please feel free to send me a message and Iโd be happy to speak with you and help you figure out a solution. I can... Source: over 4 years ago
- https://docspring.com/ (super advanced features, a bit bloated). Source: almost 5 years ago
PDF.co - A low code and REST API for PDF conversion, editing, extraction, automation and more.
DocRaptor - As the only API powered by the Prince HTML-to-PDF engine, DocRaptor provides the best support for complex PDFs with powerful support for headers, page breaks, page numbers, flexbox, watermarks, accessible PDFs, and much more
Anvil PDF Filling API - The easiest way to programmatically populate any PDF
Doczilla - Effortlessly create stunning PDFs and screenshots. Seamlessly store them in your own AWS or Google Cloud Storage bucket, putting the control and creativity right at your fingertips.
