# Show HN: Chatlens – Search and browse your ChatGPT and Claude chats offline

> Source: <https://github.com/david-g-3654/chatlens>
> Published: 2026-08-13 01:36:50+00:00

**Explore your ChatGPT & Claude history — 100% in your browser.**

Drop your export and instantly get full-text search, a usage timeline, per-topic insights, and a clean reader across thousands of chats. Nothing is uploaded, tracked, or stored. Everything runs on your device.

Screenshots use built-in sample data. Your real conversations never leave your browser.

You know you asked your AI *that one thing* back in March — but the official apps
give you no real search and no way to see your own history. chatlens turns your
data export into something you can actually explore.

It's a **single HTML file with no build step and no dependencies.**

**Just open it:** double-click`index.html`

(works offline, straight from disk), or**Serve it:**`python3 -m http.server`

then visit the printed URL, or host the one file anywhere static (GitHub Pages, Netlify, an S3 bucket…).

Then load your export, or click **Explore with sample data** to try it with a
synthetic dataset — no export needed.

chatlens accepts three shapes, auto-detected:

**A single**— the standard ChatGPT/Claude export. Drop it or click to choose.`conversations.json`

**A folder of per-conversation files**— some ChatGPT exports split each chat into its own`.json`

. Drag the whole folder onto the page, or use**"select a whole folder."****Multiple files at once**— select any number of`.json`

files together.

**Getting the export**

**ChatGPT**→ Settings → Data controls → Export data → unzip the emailed archive.** Claude**→ Settings → Privacy → Export data → unzip.

Both provider formats are detected automatically. chatlens reconstructs each conversation's canonical thread (following the active branch), so regenerated / edited-away branches are excluded from counts — you see the conversation as it stands.

Everything is indexed in-browser in a background Web Worker, so the UI never freezes. Measured on desktop Chrome (M-class laptop):

| Export size | Conversations | Messages | One-time index | Search |
|---|---|---|---|---|
| 30 MB (real export) | 222 | 4,362 | ~1.9 s | 6–15 ms |
| 53 MB (synthetic) | 2,446 | 50,000 | ~7.8 s | ~70 ms |
| 85 MB (synthetic) | 4,857 | 100,000 | ~13 s | ~120 ms |

**Indexing is a one-time cost on load**, shown with a progress bar, and scales roughly linearly with total text.** Search stays fast**(well under a quarter-second) even when a query matches tens of thousands of messages.** Honest ceiling:**past ~100k messages / a few hundred MB, indexing runs into the tens of seconds and memory use climbs (the index keeps a lowercased copy of message text, so peak RAM is a small multiple of the file size). It's built for real personal histories — thousands to ~100k messages — not for indexing a shared multi-account archive. Extremely large exports may be slow or memory-bound on low-RAM devices.

**Full-text search** across every message, built as an in-browser inverted index.- Multi-word queries match messages containing
**all** the words. `"quoted phrases"`

for exact matches.`/regex/`

for regular expressions (e.g.`/colou?r/`

).- Filter by
**you** vs**the AI**, and jump straight from a result into the reader.

- Multi-word queries match messages containing
**Timeline**— messages per month, plus a day-of-week × hour-of-day heatmap.** Insights**— totals, words written, busiest day, peak hour, models used, longest conversations, and what you talk about most.** Reader**— a clean serif reading view of any conversation with lightweight Markdown (code blocks, lists, bold, links) and per-message model labels.**Light & dark themes**(paper by default; a warm "reading at night" dark mode).

**No backend, no network calls.** Open your browser's Network tab, or disconnect from the internet — it works the same. Reload the tab and all data is gone.- Parsing and indexing run in a
**Web Worker**; the main thread only renders. If a browser blocks Blob-URL workers (some`file://`

setups), it transparently falls back to a same-interface main-thread parser. - The web client is a single vanilla HTML/CSS/JS file — easy to audit end to end.

No cloud, no LLM calls, no "continue this chat." chatlens reads and understands your existing history; it doesn't talk to any model.

MIT