Fill basic AcroForm fields from a JSON field-value map.
Drop a PDF here or click to browse
This PDF is processed in your browser and is not uploaded to opentools.
Reviewed 2026-08-15
Fill PDF Forms reads and fills AcroForm fields without a dedicated application. It sits in the opentools PDF Forms collection and is built on pdf-lib and pdf.js, so the work happens on your own device instead of on a server you have to trust with the file.
Everything runs inside the current browser tab. The PDF on your device is read, never uploaded — the tool writes a separate output for you to inspect and download. No account, no queue, and no watermark on the result.
Encrypted PDFs must be unlocked first, and PDFs with damaged cross-reference tables may fail to parse. Use a recent desktop build of Chrome, Firefox, Safari, or Edge for the widest format support and the most headroom on large files.
Yes — no usage limits, no paywalled settings, no account, and no watermark on the output. opentools is funded as a free utility, not a freemium trial.
No. The processing pipeline is pdf-lib and pdf.js running inside your browser tab, so the PDF never leaves your device. Anonymous page analytics still load, but they carry no file content.
No. A web page cannot silently overwrite files on your disk. The tool reads your input and produces a new file that you choose to download, leaving the source untouched.
Yes, in any modern mobile browser. Speed and the largest workable PDF depend on the device's free memory, so keep mobile jobs small and expect desktop to handle the heavy cases.
An internet connection is needed the first time so the page and its engine can load. PDF parsing runs in JavaScript and WebAssembly that is cached after the first visit, so repeat use works without a fast connection.
Browser tools can reorganize pages and add simple content without an install, but they are not full object-level PDF editors and cannot safely rewrite every paragraph, image, signature, or annotation.
Read guide →A careful PNG-to-PDF or JPG-to-PDF workflow keeps page images on your device, preserves their intended order, and ends with a check of the finished document.
Read guide →The meaningful distinction is not the interface but where bytes are processed, stored, logged, and returned.
Read guide →