Letterprove
LetterCompany
SignedSee the proofs live today→Letterprove · Attested proof for AI agents · The “EEAT” for AEO

AI agents are more diligent than humans. When evaluating 30 products, they're swayed by proof. With Letterprove, provide dynamic hard evidence that your product is the winner.

See how it works

Install in 2 minutes · Cryptographically attested · Agent-readable proof

letterprove · example vendor attestationverifying…
Vendor proof · acme.com · illustrative

Acme

Companies observed, 30d
···
Sessions, 30 days
·····
Business
········ ·· ······
Observed since
·······
sig ················ · ed25519
letterprove / attest
Adding ... <script src="https://app.letterprove.com/attest.js"
        data-key="lp_live_9f2c••••"></script>

# example output
✓ Domain    acme.com · proven by DNS
✓ Business  Acme Inc. · verified by Stripe
✓ Observed  212 companies · 4,182 sessions / 30d
→ 1 proof of acme.com published · signed hourly · agent-readable
Watch it prove

Agents are more diligent than humans

A human might skim three tabs. An agent evaluates thirty products, reading every claim, checking every source, and accounting for vendor bias. Most AI tools stop at discovery. Letterprove wins the next step: getting chosen.

  1. 01

    An agent builds a shortlist.

    It evaluates thirty products in your category, not three tabs.

  2. 02

    It checks every claim.

    Testimonials, logo walls and case studies are claims. It discounts what it can't verify.

  3. 03

    It finds your proof.

    Your proof answers with signed, current evidence that you are who you say you are.

  4. 04

    And it picks you.

    The only vendor backed by machine-verifiable evidence moves to the top of the list.

agent · evaluating 30 products
#01
Northgate Labsdiscovered
–
#02
Marketlydiscovered
–
#03
Your productdiscovered
–
#04
Brightpathdiscovered
–
#05
Corvadiscovered
–
↳ Ranked #1, backed by attested, machine-verifiable evidence.

Discovery gets you on the shortlist. Proof gets you the pick.
An illustration: the vendors and scores are invented.

How it works

Proof in three steps, live in minutes

No SDK, no data warehouse, no six-week integration. Drop in one script tag and Letterprove handles verification and attestation end to end.

01

Install

Add one script tag to your product, plus one line that tells it who signed in. No SDK. It begins observing real sign-ins the moment it loads.

02

Verify

We confirm you are who you say you are: your domain (by DNS, or by your script on a page there), the business Stripe has verified behind your Stripe account, and your usage observed directly. Not a logo wall anyone can paste.

03

Attest

One signed, hourly proof of your company: companies observed signing in, sessions, your Stripe-verified business, and since when. Counts, not customer names.

Every attestation is signed and independently verifiable — no “trust us” required.

Live proofs

A logo wall is a claim. Your proof is evidence.

Every logo on your site is an unverified claim. A Letterprove proof shows your company is who it says it is, backed by data: your domain, the business Stripe has verified behind your Stripe account, and the companies observed signing in, in counts. These are the proofs live today.

Letterstory

Signed
Companies observed
81
Sessions, 30 days
628
A Letter Company product, like Letterprove.observed through Nov 1, 5:05 PM UTC · open the proof →

Lettertrace

Signed
Companies observed
27
Sessions, 30 days
66
A Letter Company product, like Letterprove.observed through Nov 1, 5:05 PM UTC · open the proof →

Open either one and follow its verify link: an agent can request, verify and cite exactly what was signed.

Living proof

A success report that attests itself

Static case-study PDFs go stale the day you publish them. Letterprove reports are dynamic and machine-readable: always current, always signed, and built for an agent to read, verify, and quote.

Example: Acme · vendor proof · illustrativesigned hourlysigned
Domain: acme.com ✓ DNS verifiedBusiness: Acme Inc., US ✓ Stripe verifiedProof: re-signed ✓ hourly
Companies observed, 30d212Observed
Sessions, 30 days4,182Observed
Observed since2023-03Observed
Agent-readable
GET /attest/acme.json

{
  "vendor": "acme",
  "domain": "acme.com",
  "domain_verified": true,
  "stripe_business": { "verified": true, "name": "Acme Inc.", "website_matches_domain": true },
  "companies_observed": 212,
  "sessions": 4182,
  "tier": 3,
  "signature": "jL1O_z25…"
}

One endpoint for your company. Always live, always signed — the same proof your buyers see, in a form an agent can parse. Counts, never names.

Pricing

Pay only for reads agents actually make

No seats, no tiers to pick between. Every vendor gets a free allowance, then pays per proof read — and the rate drops as agents read more. Billed monthly per vendor.

0 – 25 reads
Free
every vendor, every month
26 – 500 reads
$0.20
per read
500+ reads
$0.08
per read, past 500

A “read” is one AI agent fetching one signed proof page, counted only when it comes from that agent’s published addresses. Free reads reset each billing month; nothing above the free allowance is charged until an agent actually reads your proof.

Give agents a reason to pick you.

Install Letterprove in two minutes and publish proof the agents evaluating you can actually verify: that you are who you say you are, backed by data.