The Marketplace for Vetted AI Data Labeling Providers
Skip the weeks of sourcing BPOs and agencies. Post one RFP and get standardized proposals from 50+ pre-vetted data labeling and LLM service providers.
Stop Sourcing Vendors Manually
Traditional vendor sourcing takes weeks of calls, demos, and scattered emails. Post one RFP and get standardized proposals from 50+ pre-vetted providers.
Vendor Matching
One RFP reaches every qualified provider.
Describe your project once — scope, tools, languages, headcount. We route it to pre-vetted vendors matched by domain expertise, annotation tooling, capacity, and location. No cold emails, no broker fees.
Standardized Proposals
Compare pricing, capacity, and timelines side-by-side.
Every vendor submits the same format: pricing model, team size, delivery timeline, tool expertise, and client references. No more chasing scattered emails or inconsistent quote formats.
Confidential Sourcing
Review vendors without revealing your identity.
Your company name stays hidden until you choose to share it. Browse vendor profiles, check references, compare proposals, and message providers — all without exposing who you are.
Escrow & Payments
Milestone-based escrow. Or pay vendors directly.
Fund milestones by card or bank transfer and release only when work is approved. Or pay vendors off-platform with zero penalties. Built-in protection for both sides, no lock-in.
50+ Vendors Across Every Major Annotation Platform
Pre-Vetted Vendors
Proposals per RFP
Free to Post
From RFP to Vendor in Days, Not Weeks
Post one RFP and let qualified vendors come to you. Compare standardized proposals, message anonymously, and start working on your terms.
Step 01
Post Your RFP
Describe your project once — scope, annotation tools, languages, team size, and timeline. Toggle anonymous if you want to keep your company hidden. Your RFP is live in minutes, not weeks.
- Structured RFP form: specify domains, tools, languages, and capacity needs
- Post anonymously — your company name stays hidden until you choose to reveal it
- 100% free to post. No sales calls, no contracts, no commitments.
Step 02
Get Matched to Qualified Vendors
OpenTrain routes your RFP to pre-vetted data labeling and LLM service providers who match your project requirements. No cold outreach, no scheduling demos, no broker fees.
- Vendors matched by domain expertise, annotation tooling, language coverage, and capacity
- Each vendor is pre-vetted with verified client references and past project history
- Global coverage: providers across the US, UK, Philippines, India, Kenya, and more
Step 03
Compare Proposals Side-by-Side
Every vendor submits the same standardized proposal format: pricing model, team size, delivery timeline, tool expertise, and client references. Compare in one inbox instead of chasing scattered emails.
- Standardized proposals with pricing, capacity, timelines, and references
- Message vendors directly to ask questions — all in one place
- Side-by-side comparison so you can shortlist in days, not weeks
Step 04
Select Your Vendor and Start Working
Choose your vendor and begin the engagement on your terms. Pay them directly via invoice, or use OpenTrain's optional escrow for milestone-based payments with built-in protection. No lock-in either way.
- Pay vendors directly off-platform with zero penalties — most teams do
- Optional escrow: fund milestones and release only when work is approved
- No exclusivity. Work with multiple vendors simultaneously if you need to.
Find Your Next Data Labeling Partner in Days, Not Weeks
Post one RFP and get standardized proposals from 50+ pre-vetted data labeling and LLM service providers. Compare pricing, capacity, and references in one inbox. 100% free to post.
Describe Your Project Once, Get Proposals From 50+ Vendors
Post your project scope, tools, languages, and headcount requirements. Our system matches you with qualified vendors who respond with standardized proposals. Free to post, no commitment.
One Inbox for Every Proposal
- 50+ pre-vetted data labeling vendors
- Standardized proposals in one inbox
- Anonymous sourcing — reveal when ready
- Optional escrow with milestone payments
Source Vendors for Any AI Data Program
Post an RFP for any project type below. Our vendor network covers every major AI data workstream — from LLM training to structured annotation.
Post-Training & Alignment
RLHF preference ranking, DPO pair generation, and reward model training data. Our experts evaluate and rank model outputs so your models learn what good looks like.
Reasoning & Verification
Expert evaluation of chain-of-thought reasoning, process reward annotation, and verification of math, code, and logic outputs.
Red Teaming & Safety
Adversarial prompt crafting, jailbreak discovery, bias evaluation, and safety alignment testing.
Domain Expert Annotation
PhDs and professionals in mathematics, medicine, law, finance, and engineering providing expert-grade training data.
Evaluation & Benchmarking
Human evaluation of model outputs, benchmark creation, A/B preference testing, and ongoing quality monitoring.
Multimodal & Multilingual
Vision, audio, video, and document annotation with cross-modal alignment across 118+ languages.
LLM & Agents
Find pre-vetted agencies and BPOs specializing in RLHF, evaluation, preference data, red teaming, and code QA.
LLM Evaluation 
Red Teaming 
Hallucination Audits 
RLHF & Preference Data 
Supervised Fine-Tuning 
Code Generation Review 
Function Calling 
Computer Use Agent Training 
Reasoning Step Verification 
Multilingual AI Training 
Reasoning Problem Creation 
Agent Simulations 
RL Environment Design Data Labeling
Source vendors for image, video, LiDAR, document, text, and audio annotation at scale across any domain.
Document Annotation 
Image Annotation 
Segmentation 
Video Annotation 
Text Annotation 
Speech and Audio Labeling 
Time Series Annotation 
Point Cloud Annotation 
Medical Imaging Annotation 
Satellite Imagery Annotation Vendor Marketplace FAQ
Common questions about sourcing data labeling vendors on OpenTrain.