Alternative · Smallpdf
AttachKit vs. Smallpdf — privacy-first vs. server-side processing
Smallpdf: Browser-based PDF tools — convert, compress, edit, sign.
Smallpdf is a popular Swiss-based browser PDF tool with a big feature surface — convert, compress, merge, edit, OCR, sign, fill. Its core architecture: you upload, they process server-side, you download. AttachKit's architecture inverts that: the PDF parsing/editing happens entirely in your browser via WebAssembly. Both are usable in a browser; the privacy posture is fundamentally different.
Why pick AttachKit for these cases
- PDF bytes never uploaded — proven by inspecting your browser's network tab.
- AI auto-fill from saved profile.
- End-to-end encrypted send-to-sign.
- Same Pro price ($12/mo) — but private. Or $120/yr ($10/mo) annually.
Side-by-side
A marks the side with the genuine advantage on that row — honestly, including the few where Smallpdf wins.
Where your PDF is processed
SmallpdfUploaded to Smallpdf's servers (Switzerland), processed, sent back. Auto-deleted within ~1 hour per their policy — but it does leave your device.
AttachKitEntirely in your browser — the bytes never leave the page. Open your Network tab and watch: nothing is uploaded.
Price
SmallpdfFree with daily limits. Pro $12/mo; Team ~$8/seat (annual).
AttachKitFree: unlimited fill + 15 signed PDFs/mo. Pro $12/mo unlimited (or $120/yr — $10/mo).
AI auto-fill
SmallpdfManual form filling only.
AttachKitAI fills the form from your saved profile — the flagship feature.
Recipient signup for sent docs
SmallpdfRecipient may have to create a Smallpdf account.
AttachKitNever.
Tool breadth
Smallpdf~21 tools — convert, compress, merge, split, rotate, OCR, fill, sign, redact, watermark, and more.
AttachKitA full browser-side toolkit — fill, sign, redact, convert (PDF↔JPG/Word/Excel), compress, merge/split, watermark, OCR, compare — none uploaded.
Switching questions, answered
- Does AttachKit compress and merge PDFs, or do I need Smallpdf for that?
- AttachKit does both — Compress shrinks file size and Pages merges, splits, and reorders, plus convert, watermark, and OCR. All of it runs in your browser with nothing uploaded, so for most people there's no reason to keep both.
- Is processing PDFs in the browser slower?
- For typical documents (under 10MB), no — local CPU is plenty for parsing and editing. For very large or complex PDFs, server-side processing like Smallpdf's can be faster. Trade speed for privacy.
- What about iLovePDF, Sejda, PDF24, or PDFgear?
- We have detailed comparisons for each (linked below). The same pattern holds across all of them: most browser PDF tools upload your file to their servers — even the privacy-conscious ones like Sejda only auto-delete it afterwards — whereas AttachKit processes the file in your browser, so it's never uploaded in the first place.
Try AttachKit now
Drop a PDF — no signup. Unlimited fill & redact in your browser, plus 15 free signed PDFs every month.
Switching for good? Save your details once — every future form auto-fills.