Truely is a travel platform with 200 pages of content and a landing page to maintain across 32 languages. They started with the same approach most teams do: raw OpenAI API calls. It didn't hold.

The before-state: no control#

"We made the rookie mistake of using raw OpenAI for translations," recalls Sebastiaan van Leeuwen, Product Manager at Truely. "We had 32 languages that nobody could control. German was terrible. Dutch was worse."

Stateless LLM calls are the localization equivalent of building without a foundation. Each request starts from zero context. There is no glossary, no brand voice, no record of how the product terminology should read in German versus Dutch versus Russian. The model makes a fresh guess every time. Across 32 languages and 200 pages, those guesses compound into drift that nobody can see until it's in production.

The team tried the standard alternatives. Human translators meant weeks of coordination, plus translators who didn't know the product. Crowdin added process without solving the root problem.

"Crowdin felt like opening an airplane cockpit," says van Leeuwen. "Too many buttons, too many features we'd never use. We needed something focused, not a Swiss Army knife of complexity."

Switching to a localization engine#

The difference with Lingo.dev was architectural, not cosmetic. A localization engine is stateful: it persists Truely's product terminology, brand voice configuration, and per-locale instructions across every request. Where raw OpenAI calls made a fresh guess at "provider" every time, the localization engine resolves it from the glossary before the model generates a single token.

Truely needed a Directus CMS integration with parallel processing for their content pipeline. Veronica, Lingo.dev's co-founder, shipped the integration in days.

"Their co-founder didn't just understand the problem – she shipped a solution in a couple of days. That's the kind of partner you want for core infrastructure."

Results#

The quality improvement was immediate and measurable.

• Dutch translations read naturally – van Leeuwen flagged this specifically because natural Dutch output from AI is rare
• Russian text automatically fits Truely's UI constraints despite Russian words running longer than their English equivalents
• A custom glossary enforces consistent brand terminology across all 32 languages
• Zero ongoing configuration required for automated translations
• Developers freed from translation management entirely

"The quality surprised everyone," says van Leeuwen. "Dutch translations read naturally, which is rare for AI. Russian, despite having longer words, fits perfectly in our UI. And the glossary feature lets us maintain precise control over our brand voice."

The underlying mechanism: the localization engine injects brand voice rules and per-locale instructions at inference time. Russian receives instructions about character budget constraints; Dutch receives brand voice configuration that shapes register and phrasing. The same configuration applies to every request, every page, every release.

The practical outcome#

Truely maintains 200 pages across 32 languages with zero translation management overhead. The localization engine handles new content automatically. The glossary prevents terminology drift. Quality is measurable and improvable.

"It's rare to find a tool that solves a complex problem without adding complexity," concludes van Leeuwen. "Lingo.dev did exactly that."