Developer API · Live

The file-conversion & PDF engine behind FormatFuse, as an API.

Privacy-first file processing for backends and AI agents. Flat, predictable pricing — no credit math. Run the conversions your browser tools can't reach, server-side.

Get your free key See the API

Free tier · 500 conversions/mo · no card required

Privacy-first

Files are processed only to fulfil your request — not retained long-term, never used to train anything.

Flat, predictable pricing

1 API call = 1 conversion. No credit packs, no per-operation multipliers, no month-end surprise math.

Built for AI agents

Plain REST + bearer auth, plus an MCP server so Claude Code, Cursor and Replit can call it as a tool.

The same proven engine

The conversion core behind 140+ FormatFuse tools — now callable from your backend.

Start free in 30 seconds

Drop your email and we'll mint a free API key on the spot — 500 conversions a month, no card. Upgrade any time from the pricing below.

Free tier · 500 conversions/mo · 25 MB files · 10 req/min · no card required. Your key is shown once.

Hero endpoint

Compress a PDF to an exact size

Most conversion APIs only do quality-based compression — you tweak a knob and hope. FormatFuse compresses to a real target: "make this exactly 2 MB." It's our most-used web tool and a genuine differentiator, now one POST request away.

  • → One call, target size in, compliant PDF out
  • → Bearer-token auth, JSON options, binary response
  • → Under 2 minutes from key to first call
Request 
curl -X POST https://api.formatfuse.com/v1/pdf/compress \
  -H "Authorization: Bearer ff_live_•••" \
  -F "file=@report.pdf" \
  -F 'options={"target_size":"2MB"}' \
  --output compressed.pdf
Response 
HTTP/1.1 200 OK
Content-Type: application/pdf
X-FormatFuse-Output-Size: 1998874      # 1.99 MB — under target
X-FormatFuse-Quota-Remaining: 499

Your server-side agent can't open a browser tab

FormatFuse's web tools run entirely in the browser with WASM — great for people, impossible for a backend or an autonomous agent. The API closes that gap. Point Claude Code, Cursor, Replit Agent or any MCP-capable client at it and let it compress, convert, merge and extract files as a first-class tool call — with the same privacy posture as the site.

PDF

target-size
  • Compress — to an exact target size or quality level
  • Merge & split
  • Convert ↔ images
  • Rotate, watermark, page numbers
  • Protect & unlock

Image

  • Convert — JPG, PNG, WebP, AVIF, HEIC
  • Compress
  • Resize
  • Read metadata

Archive

  • Create — zip, 7z
  • Extract
  • List contents

Web

  • Read — URL → clean Markdown
  • Main-content extraction (no nav/ads)
  • Links resolved to absolute

v1 ships PDF, image and archive endpoints. Video and document validation follow after launch.

Flat pricing. No credit math.

One simple rule: 1 API call = 1 conversion. Pick a tier, know your bill. Transparent per-call overage on paid plans if you go over.

Free

$0 /mo
  • 500 conversions / mo
  • 25 MB max file
  • 10 requests / min
Get free key

Starter

$19 /mo
  • 5,000 conversions / mo
  • 100 MB max file
  • 30 requests / min
Most popular

Growth

$49 /mo
  • 25,000 conversions / mo
  • 250 MB max file
  • 60 requests / min

Scale

$199 /mo
  • 100,000 conversions / mo
  • 500 MB max file
  • 120 requests / min

Annual billing saves 20%. Need more than Scale, an SLA, or SSO? Enterprise is custom — ask on the waitlist.

Need more than Scale?

Enterprise volume, higher limits, SSO or a custom SLA — drop your email and we'll reach out. We'll also keep you posted as new endpoints land.

Get launch pricing + early access. No spam — just product updates, and you can unsubscribe anytime.

FormatFuse API — Frequently Asked Questions

How do I get started?

Grab a free API key above — drop your email and it's issued on the spot (500 conversions/mo, 25 MB files, no card). Paid tiers add higher quotas, larger files and faster rate limits; subscribe from the pricing section and your key is revealed right after checkout.

Is it really privacy-first?

Same DNA as the FormatFuse web tools. Files are processed only to fulfil your request, aren't retained long-term, and are never used to train anything. The full data-handling terms ship with the API.

How is pricing different from CloudConvert or Cloudmersive?

Flat monthly tiers with one simple rule: 1 API call = 1 conversion. No credit packs, no per-operation multipliers, and no surprise math at the end of the month — the #1 complaint developers have about credit-based APIs.

Can I call it from Claude Code, Cursor or an MCP server?

Yes — that's the primary use case. It's a standard REST API with bearer-token auth, and we're shipping an MCP server so AI agents can call file conversions as a tool. Server-side agents can't run the browser tools; the API is how they reach the same engine.

What are the file-size and rate limits?

Free covers 500 conversions/mo with a 25 MB file limit and 10 requests/min. Paid tiers scale up to 500 MB files and 120 requests/min — see the pricing section above.

Do I still need the API if the browser tools already work?

The browser tools are free and stay free. The API is for server-side work — backends, pipelines, CI, and AI agents — where there's no browser to run the WASM engine in.