Lettertrace: Monitor how AI talks about your brand

Lettertrace

2 min read Original article ↗
MITOpen source, bring your own key

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%

$

watches the assistants your buyers ask

  • Claude
  • ChatGPT
  • Gemini
  • AI Overviews

watch it trace

One run, start to finish

  1. 01

    Track a topic.

    Add what your buyers ask about. One line is enough.

  2. 02

    Generate the questions.

    Lettertrace writes the real prompts people put to assistants, dozens per topic.

  3. 03

    Ask every model.

    Claude, ChatGPT and Gemini answer. Each answer is read for mentions, position and sentiment.

  4. 04

    Trace the trend.

    Every run is a datapoint. The line tells you whether it’s working.

share of voice

Every run is a datapoint.

Every answer in your category, split between you and the brands you track. Watch your share grow, and see what moved it.

acme, 12 weeks

22% → 41%

▲ +19 pts share of voice

0%25%50%75%100%123Acme41%Notion28%Linear19%Others12%wk 1wk 4wk 8this week

Share of voice by brand, weekly
WeekAcme (you)NotionLinearOthers
Week 122%38%24%16%
Week 223%37%25%15%
Week 322%39%23%16%
Week 426%38%22%14%
Week 531%35%21%13%
Week 633%34%21%12%
Week 732%35%20%13%
Week 836%33%20%11%
Week 938%31%19%12%
Week 1039%30%19%12%
Week 1140%29%19%12%
Week 1241%28%19%12%
  1. 1Week 4: Published a comparison page
  2. 2Week 8: Cited in a Claude answer roundup
  3. 3Week 11: Competitor launched v2

features

Everything you need to diagnose AI mentions.

Bring your own key

Use your own Anthropic, OpenAI & Google keys. They’re encrypted at rest and never leave your infrastructure.

Multi-model

Monitor Claude, ChatGPT, Gemini, and Google AI Overviews side by side. Add more answer engines as they matter.

Variation generation

Turn one topic into dozens of natural prompts automatically, no manual prompt-writing.

Sentiment & recommendations

Know not just if you appear, but whether the answer speaks well of you, and recommends you.

Share of voice

See exactly how often you win the answer versus each competitor you track.

Scheduled monitoring

Run daily or weekly on autopilot and build a trend line you can act on.

open source

Yours to run, inspect, and extend.

  • MIT licensed, fork it, self-host it, make it yours.
  • Bring your own keys. No usage markup, no middleman.
  • Your data lives in your own Supabase, no vendor lock-in.

$ git clone lettertrace && cd lettertrace

$ npm install

$ cp .env.example .env.local

# add Supabase URL + keys

$ npm run dev

→ http://localhost:3000

Find out what AI says about you.

Set up your brand, add a key, and run your first monitor in minutes.

Start monitoring, free

Lettertrace - Track your AI visibility for free (using your own API keys!) | Product Hunt