Company lists · Data refreshed September 2026

Top 25 Machine learning training data companies worldwide

RevenueBase identified 266 machine learning training data companies worldwide as of September 2026 and tracks 39,629 professional contacts across them, including 3,092 with verified work emails and 1,614 with mobile numbers. India is the largest market and San Francisco the largest hub.

This list covers machine learning training data companies worldwide, 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. Country and city lists for machine learning training data companies follow the table.

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.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 5, 2026 86% judged on-target in blind review
266Companies
39,629Contacts tracked
3,092Verified emails
1,614Mobile numbers
Explore this list → Free signup · no credit card · 500 free credits

The 25 largest machine learning training data companies worldwide

Ranked by team size
Top 25 of 266 machine learning training data companies worldwide, ranked by team size, largest first. Data refreshed Sep 5, 2026. RevenueBase Smart Search rates how each company's information relates to machine learning training data companies: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Strong evidenceKirkland, WA, United StatesHQ checked Sep 5, 2026n/a19,890 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, 2026
2Strong evidenceSan Jose, CA, United StatesHQ checked Sep 5, 202610001+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, 2026
3Partial evidenceScottsdale, AZ, United StatesHQ checked Sep 5, 20261,001-5,0001,272 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, 2026
4Strong evidenceNew York, NY, United StatesHQ checked Sep 5, 20261,001-5,000977 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, 2026
5Partial evidenceMiami, FL, United StatesHQ checked Sep 5, 2026501-1,000899 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, 2026
6Partial evidenceSingapore, CA, United StatesHQ checked Sep 5, 2026201-500770 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, 2026
7Partial evidenceNew York, NY, United StatesHQ checked Sep 5, 20261,001-5,000751 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, 2026
8Indirect evidenceLos Angeles, CA, United StatesHQ checked Sep 5, 2026201-500654 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, 2026
9Strong evidenceStanford, CA, United StatesHQ checked Sep 5, 202651-200526 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, 2026
10Indirect evidenceMountain View, CA, United StatesHQ checked Sep 5, 202651-200401 contacts →

Indirect evidence

“Build Super Accurate AI with us.”

Source: RevenueBase Database · checked Sep 5, 2026
11Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 5, 202651-200356 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, 2026
12Strong evidenceNew York, NY, United StatesHQ checked Sep 5, 202651-200331 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, 2026
13Partial evidenceNew York, NY, United StatesHQ checked Sep 5, 2026201-500328 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, 2026
14Partial evidencePalo Alto, United StatesHQ checked Sep 5, 202651-200231 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, 2026
15Partial evidenceSeattle, WA, United StatesHQ checked Sep 5, 202651-200205 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, 2026
16Partial evidenceWilmington, DE, United StatesHQ checked Sep 5, 2026201-500148 contacts →

Partial evidence

“Label Your Data is a data annotation & labeling company.”

Source: RevenueBase Database · checked Sep 5, 2026
17Indirect evidenceNewark, DE, United StatesHQ checked Sep 5, 2026201-500144 contacts →

Indirect evidence

“Wow AI | Powered by AIxBlock - is an.”

Source: RevenueBase Database · checked Sep 5, 2026
18Strong evidenceHampton, VA, United StatesHQ checked Sep 5, 202651-200116 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, 2026
19Indirect evidenceRemote, United StatesHQ checked Sep 5, 202651-200107 contacts →

Indirect evidence

“Roboflow creates software-as-a-service products to make building with computer vision easy.”

Source: RevenueBase Database · checked Sep 5, 2026
20Indirect evidenceBengaluru, IndiaHQ checked Sep 5, 202651-200107 contacts →

Indirect evidence

“Fueling the AI age.”

Source: RevenueBase Database · checked Sep 5, 2026
21Partial evidenceSeattle, WA, United StatesHQ checked Sep 5, 2026n/a104 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, 2026
22Strong evidenceNoida, IndiaHQ checked Sep 5, 2026201-50089 contacts →

Strong evidence

“Macgence is a leading AI training data company at the forefront of providing exceptional human-in-the-loop solutions to make AI better.”

Source: RevenueBase Database · checked Sep 5, 2026
23Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 5, 202651-20078 contacts →

Partial evidence

“HumanSignal enables data science teams to build AI models with their company DNA.”

Source: RevenueBase Database · checked Sep 5, 2026
24Strong evidenceWilmington, DE, United StatesHQ checked Sep 5, 20261,001-5,00076 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, 2026
25Partial evidenceLevittown, NY, United StatesHQ checked Sep 5, 20261,001-5,00074 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, 2026

Showing 25 of 266 machine learning training data companies worldwide

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 3,092 reachable decision-makers.

Free signup · no credit card

View the full list →

Machine learning training data companies worldwide at a glance

As of Sep 5, 2026
7.8%Verified-email coverage
4.1%Mobile-number coverage
149.0Average contacts per company
11-50Median size (employees)
8.3%Largest-city concentration · San Francisco
Sep 5, 2026Page data refreshed

Companies by employee count

1-10
65
11-50
94
51-200
65
201-500
26
501-1,000
8
1,001-5,000
6
5,001-10,000
1
10001+
1

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.
Coverage
2 countries, largest first: India, the United States. Country and city lists for machine learning training data companies are linked below.
What qualifies
Companies worldwide 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.
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, 3,092 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 between September 5, 2026 and September 14, 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.

Machine learning training data companies by location

2 lists · largest first

Every Machine learning training data companies list RevenueBase publishes, by country and city. Counts are matching companies in each list as of its own refresh date.

Countries

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 worldwide?

RevenueBase identified 266 machine learning training data companies worldwide 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 country has the most machine learning training data companies?

India leads with 137 companies, followed by the United States (129). Every machine learning training data companies list by country and city is linked on this page.

Which city has the most machine learning training data companies?

San Francisco leads with 22 headquartered companies, followed by Bengaluru (16) and Kolkata (12).

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 3,092 verified decision-maker contacts tracked across these 266 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled from the company graph between September 5, 2026 and September 14, 2026.

Ready to reach these companies? Verified emails and direct dials for all 266 machine learning training data companies worldwide. Start with a free account, no credit card.

Download this list →

Related lists

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.