Company lists · Data refreshed September 2026
Top 25 Annotation services for machine learning based in the United States
RevenueBase identified 88 annotation services for machine learning headquartered in the United States as of September 2026 and tracks 7,863 professional contacts across them, including 908 with verified work emails. San Francisco is the largest hub.
This list covers annotation services for machine learning 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 27, 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 annotation services for machine learning based in the United States
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 1,272 contacts → | ||||
Indirect evidence “Objectways is an AI data solutions company trusted by Fortune 500 enterprises and high-growth AI teams worldwide.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 2 | 977 contacts → | ||||
Partial 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 27, 2026Thanks. The Data Team will review it. | |||||
| 3 | 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 27, 2026Thanks. The Data Team will review it. | |||||
| 4 | 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 27, 2026Thanks. The Data Team will review it. | |||||
| 5 | 526 contacts → | ||||
Indirect 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 27, 2026Thanks. The Data Team will review it. | |||||
| 6 | 356 contacts → | ||||
Indirect 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 27, 2026Thanks. The Data Team will review it. | |||||
| 7 | 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 27, 2026Thanks. The Data Team will review it. | |||||
| 8 | 148 contacts → | ||||
Partial evidence “Label Your Data is a data annotation & labeling company.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 9 | 144 contacts → | ||||
Indirect evidence “Wow AI | Powered by AIxBlock - is an.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 10 | 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 27, 2026Thanks. The Data Team will review it. | |||||
| 11 | 107 contacts → | ||||
Indirect evidence “Roboflow creates software-as-a-service products to make building with computer vision easy.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 12 | 104 contacts → | ||||
Indirect 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 27, 2026Thanks. The Data Team will review it. | |||||
| 13 | 95 contacts → | ||||
Partial evidence “CVAT (Computer Vision Annotation Tool) is a leading platform for building high-quality visual datasets for vision AI.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 14 | 78 contacts → | ||||
Indirect evidence “HumanSignal enables data science teams to build AI models with their company DNA.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 15 | 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 27, 2026Thanks. The Data Team will review it. | |||||
| 16 | 74 contacts → | ||||
Indirect evidence “Anolytics is a leading provider of AI data solutions, with offices in India and the USA.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 17 | 59 contacts → | ||||
Indirect evidence “Centaur.ai data empowers you to build and deploy high-stakes AI.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 18 | 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 27, 2026Thanks. The Data Team will review it. | |||||
| 19 | 54 contacts → | ||||
Indirect evidence “Our mission is to help AI solutions save costs and increase performance.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 20 | 48 contacts → | ||||
Partial evidence “Alegion has the most powerful and flexible annotation platform for training data in market.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 21 | 45 contacts → | ||||
Strong evidence “With a deep dedication to creating ground-breaking tools plus large-scale human insight, we address the pain points of curating data for machine learning and other artificial…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 22 | 39 contacts → | ||||
Strong evidence “Data Labeler specializes in providing reliable and high-quality training data sets for Machine Learning/Artificial Intelligence initiatives.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 23 | 36 contacts → | ||||
Indirect evidence “AI Inspired by Data " maadaa.ai, founded in 2015, is a comprehensive AI data service company supplying the AI industry with professional data services in text, voice, image, and…” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 24 | 30 contacts → | ||||
Indirect evidence “Every vision model starts with labeled data.” Source: RevenueBase Database · checked Sep 27, 2026Thanks. The Data Team will review it. | |||||
| 25 | 26 contacts → | ||||
Partial evidence “We are a data services company specializing in data collection and annotation for Large Language Models (LLM), generative AI, and computer vision.” Source: RevenueBase Database · checked Sep 27, 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: annotation services for machine learning. 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 annotation services for machine learning.
- Partial evidence
- Its own public description names part of annotation services for machine learning, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name annotation services for machine learning. 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 88 annotation services for machine learning based in the United States
See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 908 reachable decision-makers.
Free signup · no credit card
Annotation services for machine learning based in the United States at a glance
As of Sep 27, 2026Companies by employee count
Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 88 companies.
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 annotation services for machine learning, 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 “annotation services for machine learning”. 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 annotation services for machine learning), 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 annotation services for machine learning, 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, 908 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 27, 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 annotation services for machine learning, 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 annotation services for machine learning are there based in the United States?
RevenueBase identified 88 annotation services for machine learning 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?
Objectways, headquartered in Scottsdale, tops this list with the largest team on record.
Which city has the most annotation services for machine learning?
San Francisco leads with 12 headquartered companies, followed by New York (9) and Los Angeles (5).
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 908 verified decision-maker contacts tracked across these 88 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 27, 2026.
Ready to reach these companies? Verified emails and direct dials for all 88 annotation services for machine learning based in the United States. Start with a free account, no credit card.
Download this list →Related lists
Annotation services for machine learning by geography
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.
More company lists
- All company lists
- Lists by location
- Lists A-Z
- New lists
- Annotation services for machine learning based in India
- AI companies based in the United States
- Cybersecurity companies based in the United States
- Manufacturing companies based in the United States
- Media companies based in the United States
- Oil and gas companies based in the United States