I built a 100% private WhatsApp chat analyzer (Zero servers, zero tracking)

Description and use

PurpleChats is a fully client‑side WhatsApp chat analyzer that processes data in the browser without servers, ensuring privacy and fast performance.

Problem

Existing chat analysis tools require uploading private conversation archives to remote servers, compromising user privacy.

Outcome

PurpleChats delivers a fully client‑side WhatsApp chat analysis experience, achieving sub‑200 ms processing for 30,000 messages while maintaining 60 fps UI performance.

Workflow

• 1. Export WhatsApp chat as a .zip file
• 2. Open PurpleChats in a browser
• 3. Upload the .zip file
• 4. In‑memory unzipping with fflate
• 5. Web Worker parses messages, normalizes dates, calculates metrics
• 6. Render 3D interactive story cards and interaction graphs
• 7. Export cards as PNG via html-to-image
• 8. Close tab to delete data

Evidence

Every calculation—from unzipping .zip exports to generating interactive Spotify Wrapped-style cards—runs strictly in the user's browser.

Source

A 30,000-message chat processes in under 180ms.

Source