Company lists · Data refreshed September 2026
Top 25 Machine learning training data companies based in the United States
RevenueBase identified 129 machine learning training data companies headquartered in the United States as of September 2026 and tracks 37,317 professional contacts across them, including 3,021 with verified work emails and 1,614 with mobile numbers. San Francisco is the largest hub.
This list covers machine learning training data companies headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 5, 2026.
Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.
The 25 largest machine learning training data companies based in the United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 19,890 contacts → | ||||
Strong evidence “Appen has been a leader in AI training data for over 25 years, providing high-quality, diverse datasets that power the world's leading AI models.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 2 | 6,538 contacts → | ||||
Strong evidence “iMerit is a leader in expert data solutions for training, tuning and evaluating AI models and computer vision systems.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 3 | 1,272 contacts → | ||||
Partial evidence “Objectways is an AI data solutions company trusted by Fortune 500 enterprises and high-growth AI teams worldwide.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 4 | 977 contacts → | ||||
Strong evidence “provides ML data operations support with Human-in-the-loop for LLMs and autonomous systems, focusing on AI/ML model training and annotation services.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 5 | 899 contacts → | ||||
Partial evidence “With 30+ years of experience in data annotation, we support AI innovators to build smarter AI.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 6 | 770 contacts → | ||||
Partial evidence “Thoth AI is a global AI data solutions company with R&D operations in Silicon Valley, working with AI teams to support the design, development, and deployment of production-grade…” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 7 | 751 contacts → | ||||
Partial evidence “Cogito Tech is a global managed service provider specializing in scalable data development tailored for AI model development.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 8 | 654 contacts → | ||||
Indirect evidence “Productive Playhouse is the execution partner technical program managers trust when scale, compliance, and quality can’t slip.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 9 | 526 contacts → | ||||
Strong evidence “Pareto.AI is a talent-first human data collection platform for AI research, empowering the top 0.01% of expert labelers to deliver the highest-quality training data.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 10 | 401 contacts → | ||||
Indirect evidence “Build Super Accurate AI with us.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 11 | 356 contacts → | ||||
Partial evidence “SuperAnnotate bridges the gap between cutting-edge AI innovation and the high-quality human data that powers it - helping advanced AI teams build more intelligent models.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 12 | 331 contacts → | ||||
Strong evidence “DataForce delivers high-quality, multimodal training data and services to power the next generation of AI.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 13 | 328 contacts → | ||||
Partial evidence “Shaip, by Ubiquity, provides end-to-end AI data services-data collection, licensing, validation, transcription, and annotation-across text, audio, image, and video.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 14 | 231 contacts → | ||||
Partial evidence “Abaka AI delivers human intelligence data for frontier AI, helping power advanced systems through a trustworthy data platform.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 15 | 205 contacts → | ||||
Partial evidence “Defined.ai is the leading provider of ethical AI data, offering the world’s biggest ethical AI data marketplace alongside subscriptions for flexible data access and custom…” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 16 | 148 contacts → | ||||
Partial evidence “Label Your Data is a data annotation & labeling company.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 17 | 144 contacts → | ||||
Indirect evidence “Wow AI | Powered by AIxBlock - is an.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 18 | 116 contacts → | ||||
Strong evidence “Liberty Source PBC is a U.S-based provider of human-in-the-loop data services that help companies realize maximum value from their Artificial Intelligence, Machine Learning, and…” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 19 | 107 contacts → | ||||
Indirect evidence “Roboflow creates software-as-a-service products to make building with computer vision easy.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 20 | 104 contacts → | ||||
Partial evidence “The AI Data Labeling Marketplace: Find, hire, and securely pay vetted AI Trainers/data labelers across 110+ countries & any domain expertise.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 21 | 78 contacts → | ||||
Partial evidence “HumanSignal enables data science teams to build AI models with their company DNA.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 22 | 76 contacts → | ||||
Strong evidence “AI Workspace has bagged a unique position in deliberating Sourcing, Data Annotation, and Generative AI services thereby initializing supervised learning for Machine Learning…” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 23 | 74 contacts → | ||||
Partial evidence “Anolytics is a leading provider of AI data solutions, with offices in India and the USA.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 24 | 59 contacts → | ||||
Partial evidence “Centaur.ai data empowers you to build and deploy high-stakes AI.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 25 | 54 contacts → | ||||
Partial evidence “At Keymakr, we provide exceptional image and video data annotation, data creation, data collection, and data validation services for AI/ML computer vision projects of all sizes.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
RevenueBase Smart Search
RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: machine learning training data companies. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.
- Strong evidence
- The company's own public description of its business names machine learning training data companies.
- Partial evidence
- Its own public description names part of machine learning training data companies, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name machine learning training data companies. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.
RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.
Showing 25 of 129 machine learning training data companies based in the United States
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Machine learning training data companies based in the United States at a glance
As of Sep 5, 2026Companies by employee count
Freshness & accuracy
How recently the business emails on this list were verified
Email last verified
How this list was built
Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among machine learning training data companies, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.
- Source
- The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
- What qualifies
- Companies headquartered in the United States whose own description of what they do matches “machine learning training data companies”. Matching reads each company's description, not its industry code or its name.
- RevenueBase Smart Search
- RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names machine learning training data companies), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
- What we exclude
- Companies whose own description does not clearly place them among machine learning training data companies, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
- Match quality
- In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
- Ranking
- Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
- Verification
- Every listed company carries at least one verified work email, 3,021 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
- Refresh
- This page's figures were pulled from the company graph on September 5, 2026. Lists refresh periodically as the graph is re-checked.
- Corrections
- Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.
Frequently asked
What is RevenueBase Smart Search?
RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names machine learning training data companies, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.
How many machine learning training data companies are there based in the United States?
RevenueBase identified 129 machine learning training data companies headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.
What is the largest company on this list?
APPEN, headquartered in Kirkland, tops this list with the largest team on record.
Which city has the most machine learning training data companies?
San Francisco leads with 22 headquartered companies, followed by New York (10) and San Jose (8).
How do I get contact information for these companies?
A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 3,021 verified decision-maker contacts tracked across these 129 companies.
How current is this list?
The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 5, 2026.
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About this data
RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.
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