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About Lenz

Lenz checks factual claims against independent sources.

Each claim gets a verdict, with the sources and the reasoning behind it.

See how it works Read the API docs
  • Kosta JordanovFounder
    Product & research
  • Victoria DodevaCo-founder
    Go-to-market
Founded 2026 · Sofia, Bulgaria
Backed by
  • LAUNCHub Ventures
  • BrightCap Ventures
Startup programs
  • Google for Startups Cloud Program
  • Claude for Startups

What Lenz does

Check one claim, or a whole draft.

  • Quick check

    A first read: a verdict, a confidence and the pages the reviewers looked at.

    about fifteen seconds

  • Deep check

    Lenz investigates the claim: it researches independent sources, has models argue both sides from them, and has a panel of reviewers score the evidence. It returns a verdict, a score from 1 to 10, the sources and the reasoning. When no public record settles the claim, it answers “No Public Record” instead of a score. That doesn’t make the claim false.

    about a minute or two

  • Citation check

    For each link or DOI in a draft, whether the cited source says what the draft attributes to it, with the passage that shows it or the reason the source could not be read.

  • Draft review

    Paste a draft or a link. Lenz lists the factual claims in it, most check-worthy first, gives each a quick check and checks its citations. You choose which claims get a deep check.

The deep check can change the quick verdict. When it does, rely on the deep check: it is the one that shows its sources and its reasoning.

The deep check, stage by stage
  1. 01Framing
  2. 02Research
  3. 03Debate
  4. 04Panel Review
  5. 05Conclusion

What makes Lenz different

Vendors disclaim accuracy. Lenz warrants the verdict.

A general AI assistant’s answer comes with a disclaimer: it can make mistakes, so check important information. Lenz does not disclaim its verdict. The trace shows the work, and the warranty is what Lenz is on the hook for.

On a paid Pro or Scale plan, every full verification that qualifies carries a contractual warranty, at no extra charge.

How the warranty works

The cover

€10,000 per certificate, €500,000 across all Lenz certificates in any rolling 12 months.

The main conditions
  1. You published a warranted statement, or sent it to someone outside your organisation, after its qualified timestamp.
  2. A court or regulator later made a finding on the warranted statement that contradicted the verdict, once the time to appeal has passed or appeals are exhausted.
  3. Damages were awarded against you on that basis.

Fines, penalties, settlements and defence costs are not part of the warranty.

  • Independent

    Lenz is unaffiliated with any model vendor and sits outside the team that wrote the text. The model that wrote a draft is not an outside check on it.

  • Several vendors, one panel

    The reviewers on a deep check run on models from different vendors, and the verdict follows the panel’s middle score, so no single model decides it.

  • The work, shown

    Every deep check returns its sources and the reasoning behind the verdict, so you can judge it yourself.

  • Open research

    Our study of model disagreement is versioned and published with its methodology, data and code, under a DOI.

Team

We measured the models, then built the check.

Long before Lenz, we spent years following the skeptic movement on one practical question: how do you know what’s true and what’s not? When AI started writing the documents, answers and reports people act on, that question became an operational one.

So we measured the frontier models against recent claims. On 63% of them the models were not unanimous on the answer, and they reported high confidence while disagreeing. Read the study

Lenz was founded in 2026 by Kosta Jordanov and Victoria Dodeva, and is based in Sofia, Bulgaria.

  • Kosta Jordanov

    Founder
    Product & research

    A fourth-time founder: before Lenz he built Wiser (IPO), FITE (acquired by Triller) and Arexus (acquired by Framfab).

    LinkedIn

  • Victoria Dodeva

    Co-founder
    Go-to-market

    Two decades in marketing, at software and media companies and at a digital agency serving top brands, most recently as VP of Marketing at FITE; a Chartered Marketer (CIM).

    LinkedIn

Who uses Lenz

Built for teams shipping AI-drafted text.

Company

Lenz at a glance.

Company
Lenz IO DPK, Sofia, Bulgaria
Founded
2026
Founders
Kosta Jordanov and Victoria Dodeva
Backed by
LAUNCHub Ventures and BrightCap Ventures
Startup programs
Google for Startups Cloud Program and Claude for Startups
What it is
A fact-checking API for teams shipping AI-drafted text, used from AI assistants, automated workflows and their own code
Pricing
A free plan, and paid plans from $7.99 a month. Plans
Contract
Monthly or annual, cancel at any time; a plan runs to the end of the period paid for
Integrations
Python and TypeScript SDKs, an MCP server for Claude and ChatGPT, n8n and Zapier. Integrations
Research
Model disagreement study, with methodology, data and code
VAT number
BG208892119

Lenz is operated by Lenz IO DPK, registered in Bulgaria. EU VAT Identification Number (VATIN) BG208892119.

Questions

Lenz is operated by Lenz IO DPK in Sofia, Bulgaria. It was founded in 2026 by Kosta Jordanov and Victoria Dodeva, and is backed by LAUNCHub Ventures and BrightCap Ventures.

No. Lenz is unaffiliated with any model vendor. A deep check runs models from different vendors against independent sources, so no single vendor’s model decides the verdict.

The quick check takes about fifteen seconds and returns a verdict and how confident it is. The deep check takes about a minute or two and shows its sources and its reasoning. The deep check can change the quick verdict. When it does, rely on the deep check: it is the one that shows its sources and its reasoning.

On a paid Pro or Scale plan, every full verification that qualifies carries a contractual warranty, at no extra charge. The figures, when it pays and what is excluded are on the warranty page.

Yes, at any time, from your billing settings. Plans are billed monthly or annually; a cancellation takes effect at the end of the period you paid for, and the account then moves to the Free plan. Part-used periods are not refunded.

Write to support@lenz.io or use the contact form. People on the Lenz team read and answer those messages, not a bot.

Talk to us about anything else.