Nothing is uploaded. When you drop or pick a PDF, the tool reads it locally with the browser’s File API, renders its pages in memory with the pdf.js engine (whose worker is bundled locally, not fetched from a CDN) and rebuilds the compressed file with the pdf-lib library on your own machine. There is no server, upload, database, API or tracking in the processing path, which matters because the documents you compress for government forms — degree certificates, mark sheets, caste or income certificates, Aadhaar or other photo ID, signatures — are sensitive. They stay on your device; the tool works offline once cached, and closing the tab discards everything. The only optional network use anywhere on the site is consent-gated advertising, which never sees your files.

Government e-filing, recruitment and scholarship portals enforce strict per-file limits so their servers are not swamped by huge scans. The most common cap is 200 KB — used across exam sites such as UPSC, SSC, RRB, IBPS, NEET and JEE and many state Public Service Commission portals — but you will also see 100 KB for photos or signatures and 500 KB or 1 MB for larger documents, and the exact figure is always printed next to the upload field. This tool locks the target to 200 KB because it is the most widely required size; a good habit is to aim a little under the stated limit for headroom rather than exactly at it. If your portal asks for a different figure, AnyTool has sibling presets for other KB targets, and you can enable Force Grayscale to squeeze a stubborn colour scan further.

200 KB is a tight budget for a scanned page, so reaching it uses firm lossy compression — images are down-sampled to a lower DPI and re-encoded as JPEG, and heavy pages may be rebuilt as images. For the certificates and ID proofs people upload this is normally fine: the text reads clearly, the university or department seal stays visible and a photograph remains recognisable, which is all a verifying officer needs. Turning on Force Grayscale helps a great deal, because a colour scan is roughly three times the size of the same page in grayscale and government verification generally accepts grayscale. The tool generates three variants (Best Quality, Balanced, Smallest) and defaults to the best one that still fits, so you keep the most fidelity possible. Because compression is lossy, it is worth zooming to about 150% on the compressed file to check the signature, dates and seal are still legible before submitting; if a colour scan is very heavy, re-scanning at 150 DPI grayscale with the borders cropped gives the tool much more to work with.

The tool is 100% client-side, so it works in any modern browser on Android, iPhone, iPad, Windows, macOS or Linux without installing anything — useful when you are filling a government form on your phone and need to shrink a scanned certificate before the upload field will accept it. Because the compression happens on your own device with pdf.js and pdf-lib, it keeps working offline once the page has loaded once. One PDF is processed at a time and the practical ceiling is your device’s memory, so a very large multi-page scan is bounded by available RAM; on a phone, a heavy colour scan may compress more slowly, and enabling Force Grayscale both speeds it up and helps reach the 200 KB target.