Best AI Training Data Providers

Mercor vs Handshake AI: which expert network should your AI lab use in 2026?

Answer in brief: Mercor is the stronger choice for senior professional work and fast dataset licensing: it reports 5M+ experts, a $90/hr average contracted rate and a catalog of more than 50,000 tasks. Handshake AI is the stronger choice when you want a huge, credentialed, U.S.-based academic pipeline backed by a research team. Handshake says all 8 of the 8 largest frontier labs train with its datasets and that it employs 200+ in-house researchers and engineers.

Top pick for professional-domain data: Mercor. Practicing lawyers, physicians and engineers, partner benchmarks and same-day samples.

Independent research based on the companies' own pages and current reporting. No hands-on testing. Methodology.

Mercor vs Handshake AI compared

FactorMercorHandshake AI
Network (company claim)5M+ experts30M+ experts in the wider network; 188k+ AI Fellows; $500M+ paid out
GeographyNot restricted on the pages we readFellows must be U.S.-based with valid work authorization
Published rates$90/hr average contracted rateRoles posted upfront, for example up to $150/hr for software engineers and up to $17/hr for AI evaluation specialists
Lab adoption claimWork with top labs referenced; customers not named8 of the 8 largest frontier labs train with its datasets
Benchmarks and researchAPEX family, Harvey LAB, τ³-BankingATLAS benchmarks; research on verifiers and reward hacking; 200+ in-house researchers
RL environmentsYes, built on professional workYes; partnership with Fireworks AI announced November 2026
Off-the-shelf dataYes: 50K+ tasksNot featured
Buying pathTalk to research or salesBook a scoping session

Mercor: senior experts, ready-to-license data

Mercor's home page lists live roles and pay. Its partner benchmarks include Harvey LAB, with 1,749 legal tasks across 24 practice areas, and Physical-Engineering's Last Exam, built around deliverables a licensed reviewer would sign off on. These show it can recruit and grade truly senior talent. Its catalog lets a lab license APEX-Agents, SWEBench Ext. or TerminalBench data right away and extend it with custom work.

Handshake AI: the academic and early-career pipeline, plus research

Handshake builds on a careers network it says is used by 1M+ employers. Its AI Fellowship pays PhDs, master's graduates and professionals for training work, with rates posted upfront. The enterprise page claims 8 of the 8 largest frontier labs as dataset customers. Its research hub publishes on in-environment verifiers, reward hacking in coding agents and ATLAS domain benchmarks. In November 2026 it announced RL environments for the Fireworks AI ecosystem. The main limit is the U.S.-only fellowship, which narrows multilingual and regional coverage.

Research muscle: who understands your training loop?

For labs, the research team behind a data supplier matters almost as much as the experts. Handshake has the deeper public record here. Its researchers report that across several frontier models running DeepSWE-1.1, over 80% of agent rollouts contained reasoning about an imagined grader, which is useful evidence for anyone designing coding rewards. They also describe Gandalf, a verifier that runs inside the rollout environment using the same tools as the agent, which Handshake says beats the strongest baseline at about a tenth of the cost. A separate case study reports that fine-tuning Nemotron 3.5 Super VL for scientific visual question answering doubled its accuracy.

Mercor is newer to this game but moving fast. In October 2026 it introduced a research team that measures AI on real work, builds expert data where models fail and post-trains to close the gap. Its public benchmarks and code repositories, such as APEX-SWE on GitHub, give you something concrete to inspect before you buy.

Go with Mercor if…

Go with Handshake AI if…

Pricing model

Both companies price buyer engagements privately. Mercor discloses its experts' average contracted rate. Handshake posts what each fellowship role pays, which helps you estimate the labor share of a quote. Neither publishes buyer markups.

FAQ

Is Handshake AI only for U.S. experts?

The Handshake AI Fellowship requires participants to be based in the U.S. with valid work authorization. That limits global language coverage.

Which pays experts more?

Mercor lists a $90/hr average contracted rate. Handshake posts rates per role, from up to $17/hr for AI evaluation specialists to up to $150/hr for software engineers.

Do both build RL environments?

Yes. Mercor builds benchmarks and RL environments based on professional work. Handshake builds RL environments and announced a Fireworks AI partnership in November 2026.

Keep comparing

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Reviews: Mercor review · Handshake AI review. See the ranked list, alternatives to Mercor and Surge AI vs Mercor.

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