Compress PDF

Compress PDF is an API that shrinks a PDF by recompressing the photos inside it (usually the heaviest part of a scanned or image-heavy PDF), without touching the text.

How it works

You send the PDF and a quality level, and get it back with its JPEG images recompressed to that level. The text, fonts and document structure aren't touched.

Honest note: it only recompresses images stored as JPEG inside the PDF (by far the most common case). Other, less common internal image formats are left as-is. If the PDF is already heavily compressed or has no photos, the result might not shrink much, or at all: in that case you get the original back, never something that's actually larger.

All you need

Your API key. Create it in your dashboard with "+ Create key".
In your automation platform, an "HTTP Request" step (n8n, Make, Zapier, Pipedream…).

How to use it in n8n

Method: POST · URL: https://api.cofferdock.com/pdf-compress
Send Headers: x-api-key = your key
Send Body: binary file (in n8n: "n8n Binary File")
In Options → Response → Response Format: choose File

Options

Option	Default	What it does
`quality`	`50`	10 (smaller, more loss) to 90 (larger, almost lossless).

API overview

Endpoint: POST https://api.cofferdock.com/pdf-compress
Auth: header x-api-key: YOUR_KEY.
Input: raw PDF, or JSON { file, quality, ... }.
How it compresses: finds every embedded JPEG image (/DCTDecode) in each page's resources and re-encodes it at the requested quality with sharp/mozjpeg. Doesn't touch other internal image formats, text, or fonts.
Limits: 20 requests/min per IP. 1 call = 1 credit.

Options

Option	Default	Description
`quality`	`50`	10-90. Only affects internal JPEG images.

Example

curl -X POST "https://api.cofferdock.com/pdf-compress?quality=40" \
  -H "x-api-key: YOUR_KEY" -H "Content-Type: application/pdf" \
  --data-binary @large.pdf \
  --output compressed.pdf

Response

{ "success": true, "pdf": "JVBERi0xLjQK...", "mime_type": "application/pdf",
    "meta": { "images_compressed": 3, "original_size_bytes": 2400000,
    "size_bytes": 620000, "reduction_percent": 74, "used": 12, "remaining": 488 } }

What you get back

meta.reduction_percent tells you how much it actually shrank. By default: with the raw PDF it returns the PDF directly; with JSON it returns base64.