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OPUS-MT

github.com

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Spec score 8.5 #32 of 156 in Translation Software

Spec sheet

Purpose
OPUS-MT provides open neural machine translation models and web services.Read 12 Oct 2026 · github.com
Deployment
The web application can be installed manually or with Docker, with a separate Dockerfile for CUDA GPU use.Read 12 Oct 2026 · github.com
Integrations
The project links to OPUS-CAT, which provides a local offline engine and plugins for SDL Trados Studio and memoQ, plus custom-provider use in Wordfast CAT.Read 12 Oct 2026 · github.com
License
The OPUS-MT software repository lists the MIT license, while its downloadable pretrained translation models are listed under CC-BY 4.0.Read 12 Oct 2026 · github.com
API access
YesRead 22 Sep 2026 · github.com
API behavior
The WebSocket client sends JSON with source text and source and target language IDs, and can request language detection by setting the source to detect or DL.Read 12 Oct 2026 · github.com
Known quality limits
The project warns that many automatic evaluation scores come from simple, short Tatoeba sentences and may overstate performance on more realistic data.Read 12 Oct 2026 · github.com
Language pair configuration
The web server uses a JSON configuration to specify translation language pairs and model decoder configurations or remote hosts.Read 5 Oct 2026 · github.com
Linux service
The project documents installing a WebSocket translation service on Ubuntu.Read 5 Oct 2026 · github.com
Maintainer
The repository belongs to the Language Technology Research Group at the University of Helsinki, whose GitHub organization lists Helsinki, Finland.Read 12 Oct 2026 · github.com
Model foundation
The models are based on Marian-NMT and trained on OPUS data using OPUS-MT-train.Read 5 Oct 2026 · github.com
Model framework
The models and services are based on Marian-NMT and are mainly segmented with SentencePiece.Read 12 Oct 2026 · github.com
Model license
The repository says its downloadable pre-trained translation models are licensed CC-BY 4.0.Read 5 Oct 2026 · github.com
Model limitations
The maintainers state that current models lack filtering, data augmentation, domain adaptation, and quality control beyond automatic evaluation on selected test sets.Read 5 Oct 2026 · github.com
Privacy deployment
The related OPUS-CAT engine is described as local and offline, intended to provide confidential machine translation on local computers.Read 12 Oct 2026 · github.com
Quality limitation
The maintainers caution that many automatic evaluation scores use simple, short Tatoeba sentences and may be too optimistic for realistic data.Read 5 Oct 2026 · github.com
Training environment
The project says its model-training scripts are currently tailored to the University of Helsinki and CSC computing environment.Read 12 Oct 2026 · github.com
Training limitation
The maintainers say the model training scripts are heavily customized for the University of Helsinki and CSC computing environment.Read 5 Oct 2026 · github.com
Training limits
The project says current models lack filtering, data augmentation and domain adaptation, and that there is no quality control beyond automatic evaluation on automatically selected test sets.Read 12 Oct 2026 · github.com
Translation models
The project provides downloadable pretrained models trained on OPUS data, and the listed models use a CC-BY 4.0 license.Read 12 Oct 2026 · github.com
Translation output
The WebSocket example returns translated text along with alignment and source and target segments.Read 5 Oct 2026 · github.com
Translation workflow integration
The project points to OPUS-CAT as an NMT plugin for Trados Studio that can run OPUS-MT models.Read 5 Oct 2026 · github.com
Web application
One setup is a Tornado-based web application with a web interface and API for multiple language pairs.Read 12 Oct 2026 · github.com
Web interface and API
One included setup is a Tornado-based web application with a web UI and API for multiple language pairs.Read 5 Oct 2026 · github.com
WebSocket service
A second setup provides a WebSocket translation service with experimental API extensions.Read 12 Oct 2026 · github.com

Plans and prices

OPUS-MT models and services Free pretrained models are downloadable under CC-BY 4.0 · no commercial pricing listed Read 12 Oct 2026 · github.com

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