Why I Built a Privacy-First PDF Tool for India's Government Portals (And the Tech Behind It)

Updated

May 20, 2026

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5 min read

RahulBanerjee

RahulBanerjee

Part of series

Building in Public — PDF Pro

Every Indian who has applied for a government job, filed an ITR, or renewed their passport knows the frustration I'm about to describe.

You have spent hours gathering your documents — Aadhaar card, PAN card, marksheets, photographs. You open the portal. You upload your carefully scanned PDF. And then you see it:

❌ "File size exceeds the maximum limit of 200KB. Please upload a smaller file."

Your file is 2.1MB. You try again. 1.8MB. Still rejected. You are now frantically Googling "how to compress PDF online free" at 11:45 PM, the night before the application deadline.

Every tool you find has the same catch: upload your document to our servers first.

That is exactly the problem I set out to solve.

The Privacy Problem Nobody Talks About Think about what you are uploading when you use a typical online PDF compressor:

Your Aadhaar card (your national identity number) Your PAN card (your tax identity) Your bank statements (your complete financial history) Your ITR filings (income, assets, liabilities) These files are being sent to servers in the US, Europe, or wherever the company is hosted. You have no idea what happens to them after processing. Are they stored? For how long? Are they used to train AI models? Are they sold?

Most privacy policies of these tools are vague at best and alarming at worst.

When I dug into this problem, I realized the solution already existed in the browser. We just weren't using it.

The Solution: WebAssembly Changes Everything Modern browsers ship with a technology called WebAssembly (Wasm) — a binary instruction format that lets you run near-native speed code directly inside the browser sandbox.

Libraries like pdf-lib and Ghostscript compiled to Wasm mean you can run a full PDF compression engine entirely inside the user's browser tab.

Here is what this means practically:

Traditional Cloud Tool: User → Upload file to server → Server compresses → Download result ↑ Your private document lives on their infrastructure PDF Pro (Wasm-based): User → File loads in browser memory → Browser compresses locally → Download result ↑ Your document never leaves your computer The file never touches a remote server. Not even for a millisecond.

Building PDF Pro I built PDF Pro (

If you are a developer curious about the Wasm implementation, feel free to reach out at [email protected] . I am happy to discuss the technical architecture in more detail.

And if you are an Indian developer building tools for Indian problems — I would love to connect. This space needs more of us.

Rahul Banerjee is an independent developer based in India. He builds privacy-first productivity tools using modern web technologies.

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webassembly