Six PDF compression SaaS tools, compared on pricing, privacy, file-size limits and batch support. Honest pros and cons — no affiliate fluff.
The 3 picks (May 2026):
Founder, CEO & Lead Developer
Juraj is a Computer Science student at Comenius University in Bratislava, Slovakia, and the sole creator of FileSlim. Frustrated with inefficient and expensive compression tools, he built FileSlim from the ground up as a free, privacy-first alternative. Working entirely alone, Juraj developed every aspect of the platform—from the compression algorithms to the user interface—ensuring complete browser-based processing that never uploads files to servers. His work has helped users worldwide compress over 50 million files while maintaining complete privacy and achieving 60-90% file size reductions.
Pricing pulled from each vendor's public plans page in May 2026. Free-tier limits change frequently — verify before committing.
| Tool | Free Tier | Paid Plan | Upload Limit | Privacy | Batch |
|---|---|---|---|---|---|
| FileSlim | Unlimited, no signup | — | Browser RAM (1 GB+) | No upload (local) | Yes, browser-limited |
| Smallpdf | 2 tasks/day | $12/mo Pro | 5 GB (Pro) | Server upload | Yes (Pro) |
| ILovePDF | Limited free | $7/mo Premium | 100 MB free / 500 MB paid | Server upload | Yes (25 files) |
| Adobe Acrobat Online | Trial only | ~$15/mo (Acrobat Std) | 2 GB | Server upload | Yes (paid) |
| Soda PDF | Limited free | ~$10/mo | ~100 MB | Server upload | Yes (paid) |
| PDF24 | Unlimited free (ads) | — | ~100 MB | Server upload (EU) | Yes |
Pros: 100% browser-based — no upload, no signup, no per-file limits, no watermarks. MIT-licensed SDK available for developers. Free forever.
Cons: Compression speed depends on your CPU. No server-side batch API for headless workflows (use the SDK instead). No OCR or PDF editing features.
Best for: Anyone handling confidential PDFs, privacy-conscious users, developers who want a free SDK.
Pros: Polished UI, broad PDF feature set (compress, merge, split, OCR, e-sign), reliable across browsers.
Cons: Free tier capped at 2 tasks/day. Files are uploaded to Smallpdf servers. Subscription required for batch and large files.
Best for: SMBs that want a single PDF SaaS for all document tasks and don't mind server-side processing.
Pros: Cheapest paid tier in this list ($7/mo). Solid batch support (25 files). REST API for developers (paid).
Cons: Server upload. 100 MB free limit. UI feels dated compared with Smallpdf.
Best for: Budget-conscious teams that need batch processing.
Pros: Industry-standard quality. Tight integration with the rest of Adobe Creative Cloud. Enterprise compliance (DPA, BAA available).
Cons: Most expensive option. Requires Adobe account. Files are uploaded to Adobe's cloud.
Best for: Teams already on Adobe CC or with strict enterprise compliance requirements.
Pros: Full desktop + online combo. PDF editing features beyond compression. Reasonable pricing.
Cons: Aggressive upsell prompts. Server-side upload. Mid-tier brand recognition.
Best for: Users who want a Smallpdf alternative with a desktop app option.
Pros: Truly unlimited free use. EU-based (server in Germany — GDPR friendly). Wide tool catalog.
Cons: Ad-supported UI. Still requires server upload. Slower than browser-only tools on small files.
Best for: EU users who need free unlimited PDF tools and accept ads.
Free, browser-based, no signup. Compress your first PDF in seconds.
Get more FileSlim in Google
Tell Google you want to see FileSlim guides and tools more often. Takes one click and you stay on this page.
