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Translation engine and quality scoring for software teams, with an open-source command line tool · United States

Lingo.dev: Product, team and how it was built

Small teamFundedB2BDeveloper tools

Lingo.dev (Translation engine and quality scoring for software teams, with an open-source command line tool, United States): 5.4K GitHub stars on the open-source tool, November 2026. Evidence grade E: no revenue figure was checked. Team: 2 co-founders at the start in December 2023; 7 people on the Y Combinator page, read in November 2026. Launched 20 March 2024; still running.Added

Outcome
5.4K GitHub stars on the open-source tool, November 2026
Evidence
E no revenue figure was checked
Launch
20 March 2024
Status
Still running
Team
2 co-founders at the start in December 2023; 7 people on the Y Combinator page, read in November 2026
Outside funding
US$4.2M, as the company states; no date or split given
Main channel
Open source
No revenue figure

What is not verified

No revenue figure, customer count or round date was found. The Y Combinator page, the launch post, the pricing page, the customer stories and GitHub were read. The TrustMRR slug list holds no Lingo.dev entry. The US$4.2M, the team of 7 and the start in December 2023 are the company's own statements. The TechCrunch article of 18 February 2025 could not be opened under the pipeline's rules. No source states that a customer has paid. The customer stories are the company's own pages. This story is grade E: the business is real and its product, price and customers are described from public pages, but no revenue figure was checked. Aiolum shows it as an idea worth studying, not as proof that it makes money.

Lingo.dev sells localization for software: adapting a product's text to other languages. A localization engine is, in the company's words, a stateful translation API that holds a team's glossary, brand voice and model preferences. Retrieval augmented localization sends that stored context to the language model with every request. The company's open-source command line tool, under the Apache-2.0 license, pushes source files to an engine and writes the translations back.

Y Combinator names Max Prilutskiy and Veronica Prilutskaya as the founders. The company says it began in December 2023 at a hackathon at Cornell Tech, and that the work was full-time from February 2024. Its legal name in the footers is Replexica, Inc, and the first GitHub releases, from March 2024, carry the name Replexica. The Y Combinator page lists 7 people and says the company raised US$4.2M, from Y Combinator, Initialized Capital and the founders of Supabase and Dependabot.

No source gives a revenue figure, a customer count or a date for the US$4.2M round, so this story is grade E. The headline is a traction fact: 5.4 thousand stars on the GitHub repository, read on 12 November 2026. The pricing page lists a Production plan at US$99 a month with a sign-up button, and the company's own customer stories name seven customers. No source states that a customer has paid.

Lingo.dev: 5.4K GitHub stars on the open-source tool, November 2026. Translation engine and quality scoring for software teams, with an open-source command line tool, United States, team of 2 to 10, evidence grade E.
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01

Why did Lingo.dev work?

Four causes, in the order they mattered. Each one is a reusable lesson.

01

The founders rebuilt the product around a different buyer

The Y Combinator page says the first product translated software with AI on every commit. The founders write that this loop is about one percent of localization work. They say they rebuilt the company around localization managers and engineers, who answer for languages they cannot read.

02

A free open-source command line tool connects to the paid engines

The code is on GitHub under the Apache-2.0 license, with 5.4 thousand stars. The company says its tool runs more than 10,000 times a week. The same tool now connects to the paid engines. No source says how many users moved to a paid plan.

03

The price list passes model costs through without markup

The pricing page says the language model price passes through with no markup. The company charges US$2 per million tokens of its own infrastructure and a base of US$99 a month. The Sandbox plan has no base price, which lets a team test an engine first.

How it was built

These details come from the company's own pages, its public code and the founder's blog. They are grade C. [5, 6, 9, 10, 16]

  • The site runs on Cloudflare Workers, with React, TanStack Router and shadcn/ui, per the humans.txt file. The careers page adds Effect.ts.
  • An engine lets the team pick any model from the OpenRouter catalog. Each language pair gets a ranked fallback list, per the founder's v1.0 post.
  • AI reviewers score each translation by dimension. An independent model scores the output, and the v1.0 post says this removes self-assessment bias.
  • The command line tool needs Node.js 22 or newer. It reads 18 file formats, including JSON, Markdown and Android and Xcode strings, per the repository page.
  • Releases are made by the github-actions account on the public repository, which lists 96 pages of releases.
  • The careers page says the team uses Claude Code, MCP servers and AI agents every day to write code and review pull requests.

Tools named in the sources

Each one opens its page in the Tools tab, with every story that uses it.

02

Who tried this before Lingo.dev, and why did they fail?

Three companies in our database of failed startups promised to remove manual work from a developer's or a business's daily task. The values below are from that database and are not independently verified. The TurboTranslations record is written with "likely" and "probably".

Died 2014 to 2023Burned US$150K

TurboTranslations

The promise

A marketplace of freelance translators with workflow tools, as a cheaper alternative to translation agencies.

Why it died

The record says a human-powered marketplace could not stand against machine translation. It does not give a firm date or a founder.

Technology change
Died 2014 to 2024Burned US$21M

Kite

The promise

AI code completion inside the editor, years before GitHub Copilot.

Why it died

The record says Kite was too early to a market that later grew, and that it made monetization mistakes.

Timing
Died 2020 to 2024Burned US$10M

CodeSee

The promise

Automatic maps of a codebase, so that developers can understand it faster.

Why it died

The record says the product was a vitamin where the market wanted a painkiller, and that its value was hard to measure.

Weak need

The failed startups come from our database of 1,749 dead startups, retold here in our own words. Its entries are AI-assisted summaries of public sources, so these cards carry no evidence grade.

What changed

TurboTranslations sold human translators through a marketplace, and the record says machine translation replaced that work. Kite and CodeSee sold developer tools whose value was hard to price. The records do not say that these were the only causes.

Lingo.dev, by its pricing page, sells usage of a language model and passes the model cost through. It also publishes a free tool that developers can test before they pay. Whether the Production plan earns enough is not shown by any source read.

03

Can one person copy Lingo.dev now?

Partly: the structure can be copied, the credibility cannot.

The sources show a free open-source tool, a free sandbox and a published usage price. A new team could copy that structure. The company also shows named customers and a Y Combinator backing that a new team would not have.

Where it is still open: Other text tasks that engineering teams repeat on every release: release notes, documentation in many languages, support articles, email templates.

  1. 1Release a free command line tool that solves one task in a developer's workflow.
  2. 2Put a paid engine behind the tool, and bill usage with the model cost passed through.
  3. 3Publish the price list and a free sandbox plan, so a team can test before it pays.
  4. 4Write a customer story for each early customer, with a quotation the customer approves.
04

How much revenue does Lingo.dev make?

Each row shows the evidence grade and the source numbers from the list at the end of this page. The grades are explained in How Aiolum verifies.

A two-founder start in December 2023, an open-source tool with 5.4 thousand GitHub stars, a published pay-as-you-go price list and no revenue figure
FactValueGradeHow we knowSources
Founders named by Y CombinatorMax Prilutskiy (CEO) and Veronica Prilutskaya (CPO)CThe Y Combinator company page lists both as founders. The launch post says the two "met eight years ago at work".[3, 4]
Start of the companyDecember 2023CThe Y Combinator page says "Founded in December 2023, after winning an AI product competition at Cornell Tech". Its fact box says "Founded: 2024". The careers page says the start was at a hackathon.[3, 5]
Earlier nameReplexicaCThe footers and the terms name "Lingo.dev (Replexica, Inc)". GitHub packages were published as replexica from March 2024. The first lingo.dev release, version 0.70.1, is dated 27 January 2025. No page states the date of the rename.[6, 8, 10, 11, 19]
First public release of the open-source tool20 March 2024CThe first GitHub release in the list is @replexica/compiler 0.0.2 of 20 March 2024. The command line tool replexica 0.18.0 follows on 28 March 2024.[10, 11]
GitHub traction, 12 November 20265.4 thousand stars, 813 forks, Apache-2.0 licenseCRead on the repository page. The company's careers page says "more than 5,000 GitHub stars" and a command line tool that runs more than 10,000 times a week.[9, 5]
Team size7 peopleCThe Y Combinator page says "Team Size: 7" and has no date. The careers page says "lean, international, remote team" without a number.[3, 5]
Funding stated by the companyUS$4.2MCThe company says it raised it from Y Combinator, Initialized Capital and the founders of Supabase and Dependabot. No date or split is given. A TechCrunch article of 18 February 2025 is listed on the Y Combinator page and was not opened.[3, 4, 18]
Production plan priceUS$99 a month base plus usageCThe company's pricing page lists it with a "Set up Lingo.dev" button that points to a sign-up page. It lists credits with automatic top-up as the billing method.[2]
Terms of service on feescustom quotesCThe terms, last updated 7 May 2026, say fees are flexible and quoted for each project. This differs from the public price list.[8, 2]
Customers named by the companySoSafe, Cal.com, Jarvi, Laurel, Papermark, Scribe, TruelyCThe company's customer stories, dated 29 and 30 January 2025 and 5 and 25 June 2026. A Laurel manager is quoted there saying "The enterprise pricing was fair".[12, 13, 14]
Time from first release to the November 2026 status31 monthscalcCalculated: 20 March 2024 to 12 November 2026.[10, 9]

How to read this table. Grade C is the company's own statement on its own page, or a public record that the company keeps. A "calc" value was computed on this page. No value is grade A or B.

Lingo.dev prices read from the company's pricing page on 12 November 2026 (grade C)
PlanPer month, billed yearly (US$)Per month, billed monthly (US$)Limit
Sandbox0100K tokens a day; 7 days of data retention; community support
Production995M tokens a day; 30 days of data retention; email support
EnterpriseCustom price; annual contract; human review, SSO, 99.99% uptime SLA

The page says the bill counts processed translations and AI review runs, and that the language model price passes through with no markup. Billing is by credits with automatic top-up. The Sandbox plan has no base price. The Production plan lists a base price of US$99 a month. It adds US$0.50 per engine a month, US$2 per million tokens of Lingo.dev infrastructure and US$0.01 per AI review run.

05

When did Lingo.dev launch, and how did it grow?

From a hackathon in December 2023 to a US$99 monthly plan in November 2026, as the company's pages and GitHub show it. Each entry carries its grade.

  1. December 2023CThe company says it began at a hackathon at Cornell Tech, and that the project won best dev tool. [3, 5]
  2. 20 March 2024CThe first GitHub release appears, under the name Replexica. The command line tool replexica 0.18.0 follows on 28 March. [10, 11]
  3. 10 October 2024CThe data of the Launch YC post gives this creation date. Its text was updated on 12 November 2026 and now names SOC 2 Type II and 300 million words. [4]
  4. 27 January 2025CThe first release under the name lingo.dev, version 0.70.1, appears on GitHub. The company's customer stories on Cal.com, Papermark and Jarvi are dated 29 January 2025. [11, 13, 19]
  5. 15 March 2026CThe founder's blog post introduces Lingo.dev v1.0, with engines, glossaries and AI reviewers that score each translation. [16]
  6. 12 November 2026CThe pricing page lists Production at US$99 a month. The GitHub repository shows 5.4 thousand stars. [2, 9]

What could go wrong for Lingo.dev?

The risks are the mirror image of the causes above.

What is not verified

No revenue figure, customer count or round date was found. The Y Combinator page, the launch post, the pricing page, the customer stories and GitHub were read. The TrustMRR slug list holds no Lingo.dev entry. The US$4.2M, the team of 7 and the start in December 2023 are the company's own statements. The TechCrunch article of 18 February 2025 could not be opened under the pipeline's rules. No source states that a customer has paid. The customer stories are the company's own pages.

Logos, counters and badges are unsourced

The home page shows a customer logo list with names that have no customer story: Mistral AI, Solana, freenet, Maze, Formbricks, Opus, Tulip and ImagenAI. Only Mistral AI and Solana are also named on the Y Combinator page. The counters "300M+ words processed", "Languages 100+" and "Enterprise uptime SLA 99.99%" have no source. The footer shows SOC 2 Type II, CCPA and GDPR with no report. The nine named quotations on the home page each match a customer story.

The terms and the price list disagree

The terms of service, last updated 7 May 2026, say fees follow a custom quote and that payment terms come with that quote. The pricing page lists a Production plan at US$99 a month and a sign-up button. The documentation lists a payment error that asks the customer to top up the balance. A Wayback copy of the pricing page from 9 May 2026 already lists the US$99 plan, with an "Upgrade to Production" button. The two pages were not reconciled by any source, and no purchase was tested.

Earlier name and earlier work of the founders

The company's legal name in the footers is Replexica, Inc. No page gives the date of the rename. The GitHub tags carry both names for versions 0.70.1 and 0.71.0. The lingo.dev releases of those versions are dated 27 and 29 January 2025. The launch post also says the founders once bootstrapped a software product with customers in over 100 countries. That product is not named, and no source dates it.

Sources

The grade next to each source is the best grade that the source can support. "Read in full" means that the text of the page was downloaded and the numbers were checked in it.

  1. C Lingo.dev: Home page, read 12 November 2026
    Read in full. Source for the logo list, the counters, the nine named quotations and the product claims.
  2. C Lingo.dev: Pricing, read 12 November 2026
    Read in full. Source for the plans, the usage prices, the billing method and the sign-up button.
  3. C Y Combinator: Lingo.dev company page
    Read in full on 12 November 2026. Source for the founders, the history, the team size and the US$4.2M statement.
  4. C Launch YC post: Lingo.dev, The Localization Engineering Platform
    Read in full. Source for the post's creation date, 10 October 2024, the founders' background and the funding statement.
  5. C Lingo.dev: Careers
    Read in full on 12 November 2026. Source for the hackathon start, the GitHub and command line numbers and the team's tools.
  6. C Lingo.dev: humans.txt
    Read in full. Source for the name Replexica, Inc and the site's technology.
  7. C Lingo.dev: Privacy Policy (last updated 7 May 2026)
    Read in full. Source for the name Replexica Inc. and the age statement: not intended for children under 13.
  8. C Lingo.dev: Terms of Service (last updated 7 May 2026)
    Read in full. Source for the name Replexica Inc. and the fees section.
  9. C GitHub: lingodotdev/lingo.dev
    Read in full on 12 November 2026. Source for the stars, the forks, the license and the readme.
  10. C GitHub: releases of lingodotdev/lingo.dev, pages 96 and 95
    Read pages 96 and 95, the oldest. Source for the first release date, 20 March 2024, and the replexica 0.18.0 date.
  11. C GitHub: release lingo.dev@0.70.1
    Read in full. Source for the first release under the lingo.dev name, 27 January 2025. The release lingo.dev@0.71.0 of 29 January 2025 was also read.
  12. C Lingo.dev: Customer stories
    Read in full. Source for the list of seven customer stories.
  13. C Lingo.dev: How Cal.com Automated Localization for 36 Languages (29 January 2025)
    Read in full. Source for the date and a quotation of the Head of Engineering of Cal.com.
  14. C Lingo.dev: Laurel customer story (5 June 2026)
    Read in full. Source for the quotation that mentions the enterprise pricing.
  15. C Lingo.dev documentation: Out of credits error
    Read in full. Source for the credit balance and the automatic top-up.
  16. C Lingo.dev blog, 15 March 2026: Introducing Lingo.dev v1.0
    Read in full. Source for the engine, the model catalog and the AI reviewers.
  17. C Database of failed startups, local export
    Record pages read on the website on 12 November 2026. AI-written summaries, not independently verified. Source for the failed predecessors.
  18. C TechCrunch, 18 February 2025: Lingo.dev is an app localization engine for developers
    Could not open: TechCrunch disallows the pipeline's agent. The title and date come from the Y Combinator page. Not used for any fact.
  19. C GitHub API: tags of lingodotdev/lingo.dev that begin with lingo.dev@0. or replexica@0.7
    Read in full on 12 November 2026. The lowest lingo.dev tag is 0.70.1. Replexica tags exist for versions 0.70.0, 0.70.1, 0.71.0 and 0.71.1.
  20. C Internet Archive: Lingo.dev pricing page, copy of 9 May 2026
    Read in full. Source for the US$99 Production plan and the "Upgrade to Production" button on that date.

Run this company? Send corrections or a verified figure to aiolum@livyden.com

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