Expert contributors for every AI training need.

We source, vet, and deploy domain experts into your annotation platforms and training pipelines — delivering the data points your models need, faster than anyone.

RLHF Ranking Data Annotation Model Evaluation

Pair 7 of 30

Which response is more helpful, harmless, and honest?

Prompt: "Explain the difference between supervised fine-tuning and RLHF in language model training."

Response A

SFT trains on labeled examples with correct answers. RLHF uses human preferences to train a reward model, then optimizes the language model using reinforcement learning (PPO). RLHF better captures nuanced quality...

Response B

PREFERRED

SFT teaches the model to imitate — it learns from example outputs. RLHF teaches the model to improve — it learns from human judgments about what's better. Think of SFT as "learn to write like this" and RLHF as "learn what good writing is."

  • Helpfulness: 4/5
  • Accuracy: 5/5
  • Harmlessness: 5/5
  • Conciseness: 4/5
  • IAA Score: 0.91 | Annotator: Expert #1203
    ✓ QA Passed

Powering contributor pipelines for leading AI companies

What makes Braintrust unique in human data

Most providers rely on fragmented, multi-step screening — separate skills tests, identity checks, and days of back-and-forth. AIR's unified assessment covers skills, reasoning, language, and identity in a single session, qualifying contributors in under 30 minutes at dramatically higher conversion rates.

Our edge:

  • 2M+ Talent Network
  • AIR Unified Assessment
  • Better talent quality
  • More engaged contributors
  • Faster deployment
  • Higher completion rates
  • Hit data timelines

AIR Unified Assessment

  • < 30 min to fully qualify a contributor
  • Skills & reasoning evaluated
  • Identity verified (IDV)
  • Language proficiency assessed
  • All in one unified session

  1. Consultative Alignment

    Project Requirements

    We start by deeply aligning with you on the exact project requirements before a single expert is sourced. Every detail is locked in upfront.

    • Data type & format needed
    • Definition of success
    • Timeline & milestones

    • of data points required

    • Systems & tools in use
    • QA process & quality bar
    • Expert domain requirements
    • NDA & security requirements

  2. Global Sourcing

    The Talent Network

    Once requirements are locked, we tap into our proprietary 2M+ Talent Marketplace. We instantly match your requirements against millions of professionals globally.

  3. AI-Powered Screening

    AIR Assessment & Security

    < 30 min full assessment
    Unified skills + IDV in one session
    Higher conversion vs. fragmented tools
    Unlike tools that run skills tests, IDV, and background checks as separate steps, AIR conducts a unified assessment — evaluating skills, reasoning, language, and verifying identity all in a single conversational session. The result: qualified contributors in under 30 minutes, with higher completion rates and less drop-off.

AIR systematically assesses:

  • Behavioral fit
  • Technical skills
  • Reasoning ability
  • Language proficiency
  • Soft skills
  • Intent & motivation

The Result

Faster deployment. Higher conversion. Less drop-off.

Because skills, reasoning, and identity are verified in one unified session, qualified contributors enter your pipeline in hours — not days. Higher-quality vetting upfront means less churn and stronger output quality throughout the project.

< 30 min to qualify
Higher conversion rate
Same day deploy ready

  1. Guaranteed Execution

    End-to-End Project Management

    We don't just hand you a list of names. We manage the full output of the experts, ensuring they complete the work and create high-quality datasets on time. The Braintrust Advantage: Most others rely on manual screening and messy spreadsheets, leading to huge drop-off rates and missed deadlines. Our automated, managed process prevents churn and guarantees delivery.

Need high-quality AI training data at scale?

Our managed team of domain experts delivers RLHF, annotation, and evaluation at enterprise speed.

Real experts across every discipline.

Our contributors aren't generic crowd workers — they're credentialed professionals performing specialized work across every domain your AI training pipeline demands.

The people behind the data.

Doctors reviewing medical AI output. Engineers validating code generation. Linguists annotating in their native language. Every contributor is matched by proven expertise — not just availability.

Join 2M+ verified experts

Data & AI Annotation

  • AI Annotation Specialist
  • Data Annotator
  • Human-in-the-loop QA
  • AI Trainer
  • Prompt Engineer
  • AI Conversational Designer
  • GPT Specialist
  • Linguistic Annotator
  • Audio Transcriber
  • Transcription QA
  • Labeling QA Specialist
  • Image / Video Tagger
  • Taxonomy Designer
  • Content Rater

Software Engineering

  • Backend & API Development
  • Frontend & UI Engineering
  • Full Stack Engineering
  • DevOps & Automation
  • Data Engineering
  • Cloud Architecture & Infra
  • Security & Access Control
  • QA & Test Engineering
  • Mobile Development
  • Platform Engineering

Regulated Domains

  • Health & Life Sciences
  • Law & Policy
  • Finance & Accounting
  • Consulting & Strategy
  • Compliance & Risk
  • Privacy & Ethics
  • Insurance & Benefits
  • Governance & Standards

Creative & Content

  • Content & Copywriting
  • Marketing & Brand Strategy
  • Design & Visual Communication
  • Social & Community
  • Advertising & Campaigns
  • UX Writing & Research
  • Creative Direction
  • Multimedia & Production

Product

  • Product Management
  • Technical PM
  • Growth & Ops Strategy
  • Business Analysis
  • Product Ownership
  • Platform & Tooling Strategy
  • User Research
  • Workflow Optimization

STEM & Technical Domains

  • Physics
  • Chemistry
  • Biology / Life Sciences
  • Environmental Science
  • Electrical / Mechanical Eng
  • Mathematics / Statistics
  • Quantitative Analysis
  • Data Science / AI Research
  • Machine Learning Engineering

Multi-language capabilities across all categories — find Python developers who speak Swedish or medical annotators fluent in Mandarin.

2M+ Vetted Experts

Credentialed professionals across every major domain, ready to deploy.

Trusted by frontier AI labs worldwide.

Join the companies building the next generation of AI with Braintrust human data infrastructure.

Why teams trust Braintrust

We combine the scale of a platform with the rigor of managed services.

Your systems, our people

Our contributors work directly inside your environment — your annotation platform, your internal tools, your workflows. Your data stays secure, and we manage the people delivering the outcomes.

Speed that compounds

Ramp thousands of contributors in days, not weeks. Our pre-vetted network means we skip the months-long recruiting cycle that slows down competitors.

Quality through vetting

AIR's unified assessment layer — covering skills, reasoning, language, and identity in one session — converts better because it's faster for contributors and more rigorous for clients. Quality is built into the entry point, not bolted on as post-hoc dashboards.

True global coverage

100+ countries, 50+ languages, every time zone. Find niche experts others can't — Emirati Arabic linguists, Brazilian Portuguese coders, Japanese medical reviewers.

End-to-end managed services

We handle the full lifecycle — from sourcing to delivery — so your team can focus on building models, not managing people.

Let's scope your AI data project.

Our team will help you define the right data pipeline for your model’s needs.

Expert contributors for every AI data type

Whatever your training pipeline needs — RLHF, annotation, evals, red teaming — we supply the people to get it done.

Most Requested

RLHF Contributors

Domain experts who rate, rank, and compare model outputs — providing the human preference signals your post-training pipeline needs.

Data Annotators & Labelers

Structured annotation across text, image, video, and audio. Multi-language, multi-domain capability.

Model Evaluators

Trained evaluators assessing AI outputs for accuracy, safety, and domain correctness.

Red Team Experts

Adversarial specialists probing your models for vulnerabilities and harmful outputs.

Prompt Engineers

Specialists testing and optimizing prompt designs across input patterns and edge cases.

Domain Expert Reviewers

Credentialed specialists — doctors, lawyers, engineers, scientists — who validate AI output accuracy and provide authoritative corrections.

Verified Results Across Human Data Workflows

Proven performance backed by real client deployments — not hypothetical benchmarks.

+25,000 contributors in the past 18 months

For a leading data labeling vendor, we placed over 25,000 contributors in the past 18 months, scaling to thousands/month to support high-volume multilingual and compliance-heavy pipelines.

10,000+ candidate assessments per month

For a leading AI Training Data vendor, AIR powered 10,000+ candidate assessments/month, enabling them to onboard over 4,000+ fully vetted contributors/month into live client projects.

< 3 days to launch full-service projects

For a leading data labeling vendor, we helped them launch full-service projects in <3 days while simultaneously running AIR-based assessments around the clock to screen thousands of internal contributors.

AI Training Data FAQ

Common questions about expert sourcing, contributor management, and working with Braintrust.