How to Compress PDF Batch
When you need to compress dozens or hundreds of PDFs — end-of-month report archives, document migration projects, or storage optimization tasks — processing them one by one is painfully slow. Batch compression lets you submit multiple files in a single request and receive all compressed versions back efficiently. SublimePDF's batch endpoint handles up to 50 files per request with a single API call.
Follow the step-by-step instructions below, then use the free tool directly — no registration or download required.
Open Tool →How to Compress PDF Batch — Step by Step
Prepare your files
Collect all PDFs to compress. For API-based batch processing, ensure your files are accessible by URL or ready for multipart upload. Organize them in a directory if scripting the process locally.
Use the batch compression endpoint
POST to /api/v1/compress/batch with multiple files as multipart/form-data or an array of file URLs: { "files": ["https://storage.example.com/report1.pdf", ...], "quality": "medium" }. All files are compressed with the same quality setting.
Set compression quality
Choose 'low' (minimal reduction, maximum quality), 'medium' (balanced — 50-70% reduction for most files), or 'high' (maximum reduction). The quality setting applies uniformly to all files in the batch.
Monitor batch progress
For large batches, the API returns a batch ID immediately. Poll GET /api/v1/batch/{batchId}/status to check progress, or register a webhook to receive a notification when the batch completes.
Download compressed files
When the batch completes, download results from GET /api/v1/batch/{batchId}/results. Results are returned as a ZIP archive containing all compressed files with their original filenames.
Pro Tips
- 💡 For batches over 50 files, split them into multiple batch requests and process them in parallel — each batch runs independently on SublimePDF's infrastructure.
- 💡 Test compression quality on a representative sample of 5-10 files before running the full batch — this avoids reprocessing hundreds of files if the quality setting needs adjustment.
- 💡 Already-compressed PDFs won't shrink much further. If your batch contains a mix of large and small files, sort by file size first and focus batch compression on the largest files for maximum impact.
- 💡 Schedule batch compression during off-peak hours to avoid hitting rate limits if you have many batches to process.
Privacy & Security
All processing happens directly in your browser. Your files are never uploaded to any server — they remain on your device throughout the entire process. SublimePDF uses WebAssembly technology for fast, secure, client-side processing.
Works Everywhere
This tool works on any modern browser — Chrome, Firefox, Safari, or Edge — on desktop, tablet, or mobile. No software to install. PDF is an open ISO standard supported by all major platforms.
How to Compress PDF Batch — FAQ
How many files can I process in one batch?
Can I set different compression levels for different files in the same batch?
How long does batch compression take?
What if one file in the batch fails?
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