Convert your files instantly — Free & Secure

What makes Convertly different from other file converters?

Most online file converters work by uploading your file to a remote server, processing it there, and sending the result back. This means your documents — contracts, tax returns, medical records, personal photos — pass through infrastructure you don't control. Even services that promise to delete files "after one hour" are making a claim you can't verify.

Convertly takes a fundamentally different approach. Every conversion runs entirely in your web browser using open-source JavaScript libraries. When you drop a file onto the page, your browser reads it from your local disk, processes it in memory, and generates the output — all without sending a single byte over the network. You can verify this yourself by opening your browser's Network tab and watching for uploads during a conversion. You won't find any.

The technology behind it

Convertly uses a combination of well-established open-source libraries that run in any modern browser:

• PDF.js — Mozilla's PDF rendering engine, the same one Firefox uses to display PDFs. It parses and renders PDF pages onto HTML Canvas elements.
• pdf-lib — a JavaScript library for creating and modifying PDFs. It handles merging, splitting, compressing, and rotating without re-rendering the content.
• jsPDF — generates new PDF documents from images, used when converting photos to PDF.
• Canvas API — a built-in browser feature for image manipulation. It handles resizing, rotating, and format conversion between JPG, PNG, and WebP.
• JSZip — creates ZIP archives in the browser, used to bundle multi-page conversions into a single download.

All of these are open-source and publicly auditable. There's no proprietary code, no hidden server calls, and no data collection.

Who is Convertly for?

Anyone who works with documents and images regularly — and especially anyone who handles sensitive files. Lawyers, accountants, healthcare workers, freelancers, students, and small business owners all benefit from a converter that doesn't require trusting a third party with their data.

It's also useful for people on slow or metered internet connections, since there's no upload or download — the file stays on your device throughout the entire process. And because there's no server involved, there are no file size limits beyond what your browser can handle in memory.

Tips for getting the best results

• For sharp images from PDFs: Our converter renders at 2× resolution by default. If your output still looks blurry, the source PDF was likely scanned at low DPI — try to get a higher-quality original.
• For smaller file sizes: WebP produces files 25-35% smaller than JPG at the same quality. If you're converting for web use, try PDF to WebP or JPG to WebP.
• For merging PDFs: Compress the result afterward — merged PDFs often accumulate duplicate internal objects that inflate the file size.
• For batch conversions: Most image tools support multiple files at once. Drop them all in one go and they'll be processed together.
• For power users: Enable the Auto-download toggle in the header to skip the download confirmation and get files immediately after conversion.