Lettertrace measures how often Claude, ChatGPT, and Gemini mention your company. But there's a catch: it's free end-to-end, developer-first, and open source.
works with ChatGPT, Claude & Gemini · self-host in minutes
$ lettertrace run --project acme
› querying claude-opus-4-8 across 24 prompts…
✓ acme mentioned in 15 / 24 answers
share of voice ████████░░░░░░░░ 41%
sentiment +0.34 positive
top competitor notion · 28%
$
how it works
Add the subjects your buyers ask about, “best CRM for startups”, “email tools for agencies”.
Lettertrace writes the real questions people put to AI assistants, so you monitor how they’re actually answered.
Every run is a datapoint. Watch visibility, prominence, and sentiment move week over week.
Ingest rival brands and see your share of voice, who the models recommend, and how often.
the numbers that matter
Lettertrace turns raw AI answers into the metrics AEO/GEO teams track: visibility, share of voice, prominence, and sentiment, per topic, per model, over time.
62%
41%
+0.34
5
sample answer · claude
“For fast-growing startups, a few tools stand out. Acme is a strong pick for teams that want automation without losing their brand voice, while Notion and Linear are popular for docs and issue tracking…”
features
Use your own Anthropic, OpenAI & Google keys. They’re encrypted at rest and never leave your infrastructure. Monitor Claude, ChatGPT, Gemini, and Google AI Overviews side by side. Add more answer engines as they matter.
Turn one topic into dozens of natural prompts automatically, no manual prompt-writing.
Know not just if you appear, but whether the answer speaks well of you, and recommends you.
See exactly how often you win the answer versus each competitor you track.
Run daily or weekly on autopilot and build a trend line you can act on.
open source
$ git clone lettertrace && cd lettertrace
$ npm install
$ cp .env.example .env.local
$ npm run dev
→ http://localhost:3000 Set up your brand, add a key, and run your first monitor in minutes.