Company lists · Data refreshed September 2026
Top 25 Semantic annotation companies worldwide
RevenueBase identified 466 semantic annotation companies worldwide as of September 2026 and tracks 9,301 professional contacts across them, including 808 with verified work emails. India is the largest market and Bengaluru the largest hub.
This list covers semantic annotation 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 22, 2026. Country and city lists for semantic annotation 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.
The 25 largest semantic annotation companies worldwide
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 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 22, 2026Thanks. The Data Team will review it. | |||||
| 2 | 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 22, 2026Thanks. The Data Team will review it. | |||||
| 3 | 524 contacts → | ||||
Indirect evidence “With 27+ years of experience, Welo Data is the human-centered infrastructure for globally effective AI.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 4 | 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 22, 2026Thanks. The Data Team will review it. | |||||
| 5 | 181 contacts → | ||||
Indirect evidence “Supahands provides fully managed data labelling services for machine learning.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 6 | 160 contacts → | ||||
Partial evidence “Welcome to TAGFact, your premier media intelligence and data annotation/labeling solution.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 7 | 148 contacts → | ||||
Partial evidence “Label Your Data is a data annotation & labeling company.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 8 | 128 contacts → | ||||
Indirect evidence “Prosessor.AI is a high-grade AI/ML data provider company for a smarter world.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 9 | 116 contacts → | ||||
Indirect 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 22, 2026Thanks. The Data Team will review it. | |||||
| 10 | 115 contacts → | ||||
Indirect evidence “Digitive is a specialist AI services and staffing company headquartered in Dublin, California.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 11 | 107 contacts → | ||||
Indirect evidence “Fueling the AI age.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 12 | 106 contacts → | ||||
Indirect evidence “Data labeling solutions for artificial intelligence learning Computer Vision Natural language treatment Speech recognition” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 13 | 104 contacts → | ||||
Indirect evidence “DataEQ uses a Crowd of humans to label millions of unstructured data points.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 14 | 95 contacts → | ||||
Partial evidence “Kognic provides the most productive annotation platform for autonomy data.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 15 | 76 contacts → | ||||
Partial 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 22, 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 22, 2026Thanks. The Data Team will review it. | |||||
| 17 | 72 contacts → | ||||
Partial evidence “Globose Technology Solutions is an AI based data collection and data annotation company specialising in providing high quality training data for machine learning and artificial…” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 18 | 71 contacts → | ||||
Indirect evidence “AIMMO creates a large volume of training data accurately and quickly so that more industries and enterprises can utilize AI.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 19 | 68 contacts → | ||||
Partial evidence “With AI and machine learning being evolved as the fastest-growing technologies that offer incredible innovations that benefit various sectors of the global economy, Annotations &…” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 20 | 60 contacts → | ||||
Partial evidence “Frinksyn which is situated in West Bengal, India, where we provide workforce support for AI/Machine Learning Data Annotation and Content Moderation services, Having business…” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 21 | 59 contacts → | ||||
Indirect evidence “Centaur.ai data empowers you to build and deploy high-stakes AI.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 22 | 55 contacts → | ||||
Indirect evidence “We support companies in a broad range of AI and Data Science projects.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 23 | 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 22, 2026Thanks. The Data Team will review it. | |||||
| 24 | 48 contacts → | ||||
Partial evidence “Alegion has the most powerful and flexible annotation platform for training data in market.” Source: RevenueBase Database · checked Sep 22, 2026Thanks. The Data Team will review it. | |||||
| 25 | 47 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 22, 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: semantic annotation 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 semantic annotation companies.
- Partial evidence
- Its own public description names part of semantic annotation companies, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name semantic annotation 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 466 semantic annotation companies worldwide
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Semantic annotation companies worldwide at a glance
As of Sep 22, 2026Companies by employee count
Email recency is reported on each country list linked below.
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 semantic annotation 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
- Every country. Country and city lists for semantic annotation companies are linked below.
- What qualifies
- Companies worldwide whose own description of what they do matches “semantic annotation 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 semantic annotation 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 semantic annotation 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, 808 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 22, 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.
Semantic annotation companies by location
2 lists · largest firstEvery Semantic annotation 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 semantic annotation 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 semantic annotation companies are there worldwide?
RevenueBase identified 466 semantic annotation 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?
Sigma AI, headquartered in Miami, tops this list with the largest team on record.
Which country has the most semantic annotation companies?
India leads with 119 companies, followed by the United States (73). Every semantic annotation companies list by country and city is linked on this page.
Which city has the most semantic annotation companies?
Bengaluru leads with 13 headquartered companies, followed by Kolkata (11) and Nairobi (11).
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 808 verified decision-maker contacts tracked across these 466 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 22, 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.