The open-source label factory behind half the vision datasets you've seen
CVAT is the self-hosted annotation workbench that lets teams draw bounding boxes, polygons, and 3D cuboids on their own hardware while plugging in their own models to do the boring parts.

What it does
CVAT Community is a browser-based platform for labeling images, videos, and 3D point clouds. Teams create projects, assign annotation jobs, review each other’s work, and export to 20+ formats including COCO, YOLO, and KITTI. It runs entirely on your own infrastructure via Docker Compose, with a Python SDK and REST API for pipeline automation.
The interesting bit
The project treats your own ML models as first-class citizens: you can wire in detectors, segmenters, or trackers (SAM, YOLO, RetinaNet, etc.) through a serverless Nuclio layer to pre-label data before humans touch it. That’s a pragmatic inversion of the usual SaaS pattern where AI assistance is a premium upsell.
Key highlights
- MIT-licensed core with active maintenance since 2018
- Multi-organization support with role-based access and review workflows
- 20+ import/export formats plus direct S3/Azure/GCS storage hooks
- Pre-built serverless integrations for PyTorch, ONNX, OpenVINO, and TensorFlow models
- Grafana dashboards for tracking annotator activity and project progress
- Chromium-based browsers only; Firefox has caveats, Safari is unsupported
Caveats
- Advanced analytics, SSO, SAM 2/3, and AI agents are paywalled to CVAT Online or Enterprise tiers
- Some serverless model assets carry separate non-commercial licenses despite the MIT core
- FFmpeg dependencies pull in LGPL/GPL obligations you’ll need to track
Verdict
Worth evaluating if you need to keep data in-house and already have models to deploy against your labeling queue. Skip if you want turnkey SaaS convenience or need Safari support for your annotation team.
Frequently asked
- What is cvat-ai/cvat?
- CVAT is the self-hosted annotation workbench that lets teams draw bounding boxes, polygons, and 3D cuboids on their own hardware while plugging in their own models to do the boring parts.
- Is cvat open source?
- Yes — cvat-ai/cvat is open source, released under the MIT license.
- What language is cvat written in?
- cvat-ai/cvat is primarily written in Python.
- How popular is cvat?
- cvat-ai/cvat has 16.4k stars on GitHub and is currently holding steady.
- Where can I find cvat?
- cvat-ai/cvat is on GitHub at https://github.com/cvat-ai/cvat.