DeepL API

DeepL API gives developers programmatic access to DeepL's neural machine translation engine for building multilingual products, localising content, and automating cross-language workflows — includes text and document translation endpoints and custom glossaries for brand and technical terminology. Teams integrate high-quality translation into SaaS apps, internal tooling, and customer support pipelines with a single REST call.

Official client libraries ship for Python, Node.js, .NET, Java, PHP, and Ruby, backed by an OpenAPI specification for any other language. The API handles HTML and XML markup, translates Word, PowerPoint, PDF, and text files, detects source language automatically, and honours formal or informal tone settings across dozens of languages.

Key benefits:

• Best-in-class translation quality from DeepL's transformer-based models
• Custom glossaries locking brand terms and technical jargon across languages
• Document translation preserving formatting in Word, PowerPoint, and PDF
• Markup-aware endpoints safely translating HTML and XML content
• Formality control switching between formal and informal tone per language
• Open-source SDKs across Python, Node.js, .NET, Java, PHP, and Ruby

DeepL is headquartered in Cologne, Germany, founded in 2017, with all translation servers operated inside the European Union. The API is GDPR-compliant and ISO 27001 certified, with input text deleted immediately after translation and no data used to train public models — critical for regulated and enterprise use.