2026-10-02
Searching "compress PDF" mostly returns the same kind of tool: you upload the file, a server shrinks it, you download the result. Smallpdf, iLovePDF and Adobe's online compressor all work that way, and for a menu or a flyer that is a perfectly sensible trade. It is a worse one when the PDF is a contract, a bank statement, a scanned passport or a medical form, because the whole point of the job is to make the file smaller, not to hand a copy to someone else's infrastructure.
iLoveDevTools's Compress PDF does the work in your browser tab instead. The file is read, rewritten and downloaded locally with pdf-lib, pdf.js and your browser's own JPEG encoder. There is no upload, no account and no daily limit. Here is what it actually does, and what it does not.
Light (lossless). It removes objects that nothing points to, drops document metadata and re-saves the file with compressed object streams. Nothing visible changes and the text stays selectable. The catch is that the saving is small: a 30-page text PDF we generated went from 34.6 KB to 34.4 KB, a 0.6% saving. A PDF with big photos in it saved 0%, because Light never touches images.
Reduce image quality. This is the one most people need. It decodes each embedded JPEG, scales it down to a longest side you choose and re-encodes it at the quality you choose. Text and vector graphics are untouched, so the result is still searchable. On a 4-page, 10.7 MB test PDF full of photos, 70% quality and a 1600 px limit gave 1.67 MB, and 50% quality at 800 px gave 128 KB. Those test photos were random noise, which shrinks far more than real photographs do, so expect smaller savings on your own files and look at the before and after sizes the tool shows you before you download.
Rasterize (strongest). It renders every page to a JPEG and rebuilds the PDF from those pictures. That 10.7 MB test file became 198 KB at 110 DPI, and a 3.1 MB PDF of PNG images became 190 KB. The cost is real: the text is no longer selectable or searchable, and links and form fields stop working. Use it for scans, where the page was a picture to begin with.
If a setting produces a file that is not smaller than your original, the tool says so and does not offer the download. A tiny 873-byte test PDF came out at 3.3 KB when rasterized, and the tool refused to hand that over. Many compressors will quietly return the larger file.
Be honest about the trade. A compressor running on a server can use tools like Ghostscript, which re-samples every image type, merges duplicate images and subsets fonts. This tool only recompresses plain JPEG images: PNG-style images, images with transparency and CMYK photos are left as they are, and the result panel tells you how many images it skipped. If your PDF is mostly non-JPEG images, Rasterize is the option that shrinks it, with the text trade-off above. It also cannot open a password-protected PDF; you remove the protection first with Unlock PDF.
If the file is sensitive, or you just want it done once without an account or a daily limit, use the browser version, starting with Reduce image quality for photo-heavy files and Light for text. If you compress hundreds of files a week, need an exact target size, or your PDFs are full of non-JPEG images, a desktop tool or a paid server-side service is the better fit. For everything in between, Compress PDF is quicker than signing up for one.