DeepL
Neural translation for text and files, with a web app, desktop apps and an API that accepts glossaries and formality settings.
- Developer API
- Glossary or termbase support
- Free plan or free tier
A machine translation engine takes a sentence in one language and produces a sentence in another. Most engines today are neural models trained on large collections of translated text, and a growing number also use large language models. You reach them in two ways: through a web or desktop app where you paste text or upload a file, or through an API that your own software, translation management system or website plugin calls in the background.
The engines in this category fall into three groups. Cloud providers such as Google Cloud Translation, Azure AI Translator and Amazon Translate sell translation as one service among many, billed through the same account as your hosting. Specialist vendors such as DeepL, ModernMT, SYSTRAN, Language Weaver and Lingvanex focus on translation and often add features aimed at businesses, such as on-premises deployment or engines that adapt to your corrections. Open source projects such as LibreTranslate and Apertium let you run translation on your own servers, which matters when text cannot leave your network.
Quality varies by language pair and by type of text far more than by brand. An engine that reads well for English to German marketing copy can stumble on Japanese interface strings or Finnish legal text. Short strings with no surrounding sentence, such as a button that says "Save" or "Charge", are hard for every engine because the right word depends on context the engine never sees. The only reliable comparison is a test with your own content: pick a few hundred real sentences, run them through two or three engines, and have native speakers mark the errors that would matter to a reader.
Customization is the next thing to check. Glossaries force specific translations for product names and key terms. Custom models, offered by Google, Microsoft, Amazon and others in different forms, are trained on your own translation memories so the engine learns your vocabulary and tone. Adaptive engines such as ModernMT update from each correction a linguist makes. Ask which of these work for your language pairs, since support is often uneven.
What a featured listing costs ยท from $99 a month
Neural translation for text and files, with a web app, desktop apps and an API that accepts glossaries and formality settings.
Translation API on Google Cloud with a basic model, custom-trained models through AutoML and glossary support in the advanced edition.
Microsoft's translation service on Azure for text and documents, with Custom Translator for training a model on your own bilingual data.
AWS translation API for real-time and batch jobs, with custom terminology files and parallel data to steer output.
Adaptive machine translation that learns from your translation memories and from corrections as linguists make them.
Translation vendor offering cloud and on-premises engines, plus specialized models for fields such as legal and medical.
RWS machine translation for enterprises, deployable in the cloud or on premises, with adaptable engines and dictionaries.
Translation apps and an API, with on-premises servers for companies that need to keep text on their own hardware.
Open source translation API you can host yourself, built on the Argos Translate models, with a hosted option as well.
Open source rule-based translation platform, strongest for closely related language pairs and smaller languages.
Then look at data handling. Everything you send to an engine passes through the vendor's systems. Business plans usually promise not to store your text or use it for training. Terms can still differ between free apps, paid apps and APIs from the same company. If you translate contracts, health information or unreleased product copy, read the data terms for the exact product you will use, and consider on-premises or self-hosted options.
Finally, plan for more than one engine. Many localization teams connect several engines to their translation management system and route each language pair to the one that tested best, with a quality check in between. Pricing is usually per character, so a short trial on real volume tells you more about cost than any rate card.
Large language models have added a new option. General chat models can translate, follow style instructions and explain their choices, and some translation vendors now build on them. They can be slower and less predictable than dedicated engines on long batches, and they may add or drop content without warning, so treat them as one more engine to test, with the same checks on numbers, names and missing sentences.
There is no single answer. Accuracy changes by language pair, subject and text type, and engines are updated often. Test two or three engines on a sample of your own content and have native speakers mark the errors. Many teams then use different engines for different language pairs.
Several engines here offer this. Google Cloud Translation, Azure AI Translator and Amazon Translate have custom model or custom terminology features, and ModernMT adapts to your translation memory and corrections. You need a reasonable amount of clean bilingual text for training to help.
It depends on the product and the plan. Read the data terms for the exact service you will use, check whether text is stored or used for training, and ask where it is processed. For the most sensitive content, an on-premises or self-hosted engine keeps text on your own systems.
Not always. DeepL and several others have web and desktop apps anyone can use. The APIs are meant for developers or for connecting the engine to a translation management system or website plugin, which usually takes only an API key.