FiftyOne
FiftyOne: A broad open-source platform for annotation, dataset curation, and model evaluation. Ranked #5 of 28 in Image Annotation Software by our editors (8.6/10); pricing: Open source; best for ML teams combining annotation and model evaluation.
At a glance
- Editor score8.6 / 10
- PricingOpen source
- Best forML teams combining annotation and model evaluation
- Paid fromFree
- Model-assisted labelingYes
- Founded2018
- Facts checked20 Sep 2026
Where it wins
- Supports boxes, polygons, masks, classifications, polylines, and SAM2 annotation
- Combines annotation, review workflows, dataset curation, and model evaluation
- Offers APIs, self-hosting, exports, and integrations across data systems
Where it doesn't
- Enterprise capabilities are organized around contact-sales plans
- The broad feature set may exceed the needs of simple annotation projects
- Governed collaborative deployments require the Enterprise offering
Our verdict on FiftyOne
FiftyOne is an image and multimodal data platform from Voxel51 for computer-vision and machine-learning teams. It combines annotation, dataset curation, model evaluation, review workflows, and dataset export in one environment. Annotation covers bounding boxes, polygons, semantic and instance segmentation masks, image and region classification, polylines, and SAM2 click-to-segment annotation. Teams can also use natural-language agentic labeling and pre-label generation, define annotation schemas, manage ontologies, and apply quality gates.
Its strongest fit is for organizations that need annotation alongside broader dataset and model workflows. FiftyOne supports label-error identification, dataset curation, model evaluation, and export to COCO, image directories, classification directory trees, FiftyOne datasets, and Python or CLI workflows. Integrations include CVAT, Label Studio, V7, Labelbox, COCO, Open Images, and ActivityNet, along with Qdrant, Redis, Pinecone, MongoDB, Elasticsearch, Databricks Mosaic AI, PostgreSQL Pgvector, and Milvus. Web, Windows, macOS, Linux, API, and self-hosted options support varied technical environments.
The open-source edition suits local workflows, while FiftyOne Enterprise is positioned for collaborative and governed deployments across cloud, hybrid, on-premises, and air-gapped environments. The published Team plan includes unlimited data, unlimited model inference, SSO, and standard enterprise support. Growth adds on-premise or air-gapped deployments and premium enterprise support, while Custom adds unlimited user and guest seats, unlimited VPUs, unlimited production and development or staging deployments, and professional services. According to the vendor's pricing page, these plans are contact-sales offerings. Choose FiftyOne when annotation must connect to evaluation and data operations; a narrower tool may be a better fit for teams seeking only basic labeling.
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FiftyOne pricing
All 3 FiftyOne plans and prices →
FiftyOne fact sheet
| Free plan | Not verified |
|---|---|
| Paid from | Free |
| Annotation types | bounding boxes; polygons; segmentation masks; classifications; polylines; SAM2 click-to-segment instance segmentation |
| Image formats | JPEG; PNG; BMP |
| Model-assisted labeling | Yes |
| Dataset export | COCO; image directory; image classification directory tree; FiftyOne dataset; Python/CLI export |
| Team collaboration | Yes |
| API access | Yes |
| Deployment | Cloud, Self-hosted |
| Platforms | Web, Windows, macOS, Linux |
| Compliance & security | ISO 27001, SSO/SAML |
| Support | Email, Community, Docs |
| Built for | Small business, Mid-market, Enterprise (editorial estimate) |
| Integrations | 20 integrations: COCO, Open Images, ActivityNet, CVAT, Label Studio, V7 … See all → |
| Pricing | Open source (source) |
| Website | voxel51.com |
| Facts checked | 20 Sep 2026 |
FiftyOne integrations
FiftyOne lists 20 integrations on its own site.
- COCO
- Open Images
- ActivityNet
- CVAT
- Label Studio
- V7
- Labelbox
- Qdrant
- Redis
- Pinecone
- MongoDB
- Elasticsearch
- Databricks Mosaic AI
- PostgreSQL Pgvector
- Milvus
- LanceDB
- Hugging Face
- Ultralytics
- TwelveLabs
- Albumentations
See all FiftyOne integrations →
Alternatives to FiftyOne
- PixanoA flexible open-source choice for teams annotating 2D and 3D vision datasets.9.0
- CVATA broad CV workflow spanning manual, AI-assisted, collaborative, and programmatic annotation.8.9
- Label StudioFlexible image annotation with open-source deployment, AI assistance, and broad exports.8.8
See all FiftyOne alternatives →
FiftyOne vs the competition
- FiftyOne vs Pixano
- FiftyOne vs CVAT
- FiftyOne vs Label Studio
- FiftyOne vs Roboflow
- FiftyOne vs Supervisely
- FiftyOne vs V7 Darwin
Compare FiftyOne with any tool side by side →
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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
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