Sejda Alternative — Auto-Detect Fields, No Account

pdf2fill vs Sejda comparison

Sejda does 30+ things with PDFs. pdf2fill does one thing: fill out forms. If that's all you need, here's how they compare on that specific job.

Feature	pdf2fill	Sejda
Account required	No	No
Price	Free (5 PDFs/month)	Free (3 tasks/day, 200 pages), $7.50/month
Auto field detection	Yes (F1 accuracy: 0.85)	No, manual placement
File processing	In your browser only	Uploaded to server (deleted after 2 hrs)
Works on flat/scanned PDFs	Yes, auto-detected	Yes, but fields placed manually
Daily task limit	No daily cap	3 tasks/day on free
E-signatures	Not yet	Yes (basic)
PDF merge/split/compress	No	Yes, 30+ tools
Desktop app	No	Yes
Time to fill a PDF	~60 seconds	3-5 min (manual field setup)

The auto-detection difference

Sejda's form filler works fine on PDFs that already have built-in interactive fields. Open one, click the field, type. Simple.

The problem shows up with flat PDFs, the kind that weren't designed as interactive forms. A W-9 your client emailed you, a rental application you downloaded, a government form that's basically a scanned image. In Sejda, you'd click "Text" for each field, drag a box into position, resize it to match the blank line, and repeat for every field on every page.

pdf2fill's detection engine handles this automatically. It reads the page layout, identifies blank lines, checkboxes, and signature areas, and creates the fields for you. The engine scores F1 = 0.85 on real-world PDFs (tested on tax forms, government applications, insurance documents, and contracts). If it misses a field, one click adds it.

Where your file goes

When you use Sejda, your PDF is uploaded to their servers for processing. They delete it after 2 hours, and they're transparent about that, which is fair. But the file still leaves your computer.

pdf2fill processes everything in your browser's memory. The PDF never touches a server. When you close the tab, the file is gone from memory entirely. For documents with personal information (tax IDs, addresses, medical data), that's a meaningful difference.

When Sejda is the better choice

If you need to merge PDFs, split pages, compress files, convert formats, add watermarks, or do any of the other 30+ operations Sejda offers, use Sejda. It's a full PDF toolkit and it's good at what it does. pdf2fill only fills out forms.

Common forms people fill out here

Tax forms like the W-9, job applications, lease agreements, medical forms, insurance claims. Anything that shows up as a PDF and needs to be completed. The online PDF form filler handles all of these, and you can use it as a free PDF filler with no sign up or to fill out a PDF without Adobe.