Labelbox
The data factory for AI teams
Founded
2018
Starting Price
$0
Category
Developer Tools
Last updated April 27, 2026
About Labelbox
Labelbox is an AI data platform that provides end-to-end infrastructure for creating high-quality training and evaluation data for machine learning models. It supports multimodal annotation across text, image, video, and audio, with built-in model-assisted labeling, quality control workflows, and an expert network of 1.5M+ knowledge workers for scalable data operations.
Pros & Cons
Pros
- Supports all major data types — text, image, video, audio, and multimodal — in a single platform
- Generous free tier with up to 30 users and 50 projects for teams getting started
- Model-assisted labeling with foundation models dramatically speeds up annotation workflows
- Purpose-built RLHF and evaluation tools for frontier AI development and LLM fine-tuning
- Comprehensive Python SDK and API for seamless ML pipeline integration
Key Features
Multimodal Annotation
10+ built-in editors for labeling text, images, video, audio, and multimodal chat with support for classification, bounding boxes, segmentation, NER, and more
Model-Assisted Labeling
Integrate foundation models and custom models to auto-generate labels, enabling faster annotation with human-in-the-loop review and correction
Data Catalog & Curation
Unified data management with 25+ cloud source integrations, vector and natural language search, and intelligent data exploration and curation tools
Quality Control & Consensus
Built-in quality assurance workflows with real-time feedback, reviewer roles, consensus scoring, and performance monitoring across annotation teams
RLHF & Evaluation Workflows
Purpose-built tools for reinforcement learning from human feedback including preference pairs, reward signals, scoring rubrics, and head-to-head model comparisons
Alignerr Expert Network
Access to 1.5M+ knowledge workers across 40+ countries including 50K+ PhDs for specialized domain-expert annotation and model evaluation tasks
Pricing
Free
$0/month
- Up to 30 users
- Up to 50 projects
- Up to 25 ontologies
- 1 workspace
- Core catalog and annotation tools
Best For
Computer Vision Model Training
Create labeled image and video datasets with bounding boxes, segmentation masks, and classifications for training object detection, autonomous driving, and medical imaging models
LLM Fine-Tuning & RLHF
Generate preference pairs, reward signals, and human evaluations for reinforcement learning from human feedback workflows to align and improve large language models
NLP Data Annotation
Label text datasets for named entity recognition, sentiment analysis, text classification, and conversational AI training with collaborative team workflows
Model Evaluation & Benchmarking
Run custom evaluations with domain experts to benchmark model performance, compare models head-to-head, and identify failure modes before deployment
