LabelU

6.7easy start · #11 of 21
in AI Data Labeling Tools

Free to practise onnot on record
Free trialnot on record
Well documentedyes
Runs where you workyes

Runs on api, Mac, self-hosted, Web, Windows.

LabelU is ranked #11 of 21 in AI data labeling tools on The Geeks Club. It runs on API, macOS, Self-hosted, Web, Windows.

Compared on AI data labeling tools

Supported modalities: image, video, audio
Model-assisted labeling: Yes
Human review workflows: Yes
Custom ontologies: Yes
Deployment options: self hosted
API access: Yes

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The record

Purpose: LabelU is an open-source multimodal data annotation platform for image, video, and audio data.
Image annotation: Image tools include 2D bounding boxes, semantic segmentation, polylines, and keypoints.
Video annotation: Video capabilities include video segmentation, video classification, and video information extraction.
Audio annotation: Audio tools support audio segmentation, audio classification, and audio information extraction.
AI assisted labeling: Users can load pre-annotated data with one click and refine or adjust it.
AI auto-annotation: AI model services can automatically detect and segment image objects, including batch annotation with real-time progress tracking.
Reference models: Reference model servers include Florence-2, GroundingDINO plus SAM ViT-B, and SAM 3.
Object storage: LabelU can import annotation data from S3-compatible storage such as AWS S3 and MinIO.
Export formats: The platform supports exporting data in JSON, COCO, and MASK formats.
Deployment: Local deployment uses Miniconda, Python 3.11, pip installation, and a local server at http://localhost:8000/.
Database support: LabelU includes built-in SQLite and supports MySQL installation and migration.
API: The model server exposes a unified HTTP API with POST / and GET /health endpoints.
Model requirements: Florence-2 requires about 4GB VRAM, GroundingDINO plus SAM ViT-B about 4GB, and SAM 3 about 8GB with CUDA 12.6+.
License: The project is released under the Apache 2.0 license.

Where it ranks on The Geeks Club

Best AI Data Labeling Tools in 2026#11 of 21

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Sources

github.com/opendatalab/labelU· checked 1 Oct 2026
github.com/opendatalab/labelU/blob/main/model_serv· checked 1 Oct 2026