Data Annotation Companies: A Buyer’s Guide
Short answer: a data annotation company labels or reviews the human data used to train AI models. The right choice depends on the model you buy: a managed service (iMerit, Label Your Data) delivers finished datasets, a platform (Labelbox, Toloka) gives your team the tools or crowd, and an expert network (Scale AI’s Outlier) supplies credentialed reviewers for RLHF and evaluation. The table below compares 9 companies on service model, modalities, best use, and pricing transparency — with sources and dates, not sponsored rankings.
Demand context: the query “data annotation companies” draws about 1,900 US searches per month with commercial intent, and the adjacent term “data annotation services” carries an average cost per click of $66.05 (DataForSEO data, pulled November 9, 2026). Many existing rankings of these companies are published by a vendor on the list. This guide is published by neither — see how we evaluate.
The 9 companies, compared
| Company | Service model | Modalities | Best for | Pricing transparency |
|---|---|---|---|---|
| Scale AI | Managed service + expert network | Text & LLM data, image, video, physical AI / robotics | AI labs and enterprises running large training-data programs, including physical AI | Not disclosed |
| Appen | Managed service / global crowd | Text, speech, image, video, LiDAR & sensor fusion | Buyers needing a very large global contributor crowd, incl. physical AI data | Not disclosed |
| iMerit | Managed service | Image, video, text | ML teams outsourcing annotation production with managed QA | Not disclosed |
| Labelbox | Platform software + labeling service | Image, video, text, audio | Teams that want to run labeling in-house on vendor software | Not disclosed |
| Toloka | Crowd platform | Text, image, audio | Self-serve crowd labeling at volume | Not disclosed |
| CloudFactory | Managed service / staffing | Image, video | Ongoing labeling operations staffed as a managed workforce | Not disclosed |
| Label Your Data | Managed service | Image, video, text, audio | Cost-transparent managed annotation, incl. complex tasks | Public — ~$6 per annotator hour, time-billed |
| DataVLab | Managed service | Image, video, text | Managed annotation with EU-based teams (vendor-stated) | Not disclosed |
| BasicAI | Managed service + platform software | Image, video, text, audio | Cost-sensitive professional annotation services | Platform from $6,600/yr; services quote-only |
Pricing transparency reflects what each company publishes openly, checked November 9, 2026. Vendor pages checked: Scale AI, Appen, iMerit, Labelbox, Toloka, CloudFactory (data types), Label Your Data, DataVLab, BasicAI. “Not disclosed” means no public rate card was found in our sources — it does not mean the company is expensive or cheap. Vendor inclusion follows our methodology; no company paid for placement in this table.
How to choose
Work through these five checks in order:
- Service model fit. No internal labeling team → managed service. Existing team and tooling → platform. Frontier-model RLHF or expert evaluation → expert network.
- QA you can audit. Ask who reviews the reviewers, what inter-annotator agreement is reported, and whether you can inspect raw labels before acceptance.
- Security in writing. Data-handling terms, access controls, and retention/deletion terms belong in the contract, not the sales deck. Where we could not verify a company’s security posture from public sources, its profile says “not verified.”
- Comparable pricing. Convert every quote to the same unit — per accepted label, per annotator hour, or per project — and separate what annotators are paid from what you are charged (pricing breakdown).
- Paid pilot first. A small pilot on your own data, scored against your rubric, predicts production quality better than any case study.
What most rankings get wrong
Vendor-published “best data annotation companies” lists rank their publisher first, describe competitors in one line each, and never state pricing. Our rules instead:
- Every claim links to a dated source; anything we could not verify is labeled “not verified” or “not disclosed.”
- Each profile includes a “not suitable when” line — no vendor is right for every buyer.
- Sponsorship, if it ever exists here, will be labeled and will never change a ranking (methodology).
- Worker pay and client prices are reported separately, because conflating them is how this market hides its margins.
Comparing vendors for a specific project? Request a shortlist with your data type and volume, and the desk will reply with a sourced shortlist.
Frequently asked questions
What is a data annotation company?
A data annotation company labels, reviews, or generates the human data used to train and evaluate AI models — image and video labeling, text and speech annotation, RLHF preference ranking, and expert review. Some sell a managed service that delivers finished datasets; others sell labeling software or a crowd/expert marketplace you operate yourself.
What is the difference between a managed annotation service and a labeling platform?
A managed service (for example iMerit or Label Your Data) hires, trains, and quality-checks annotators for you and delivers a dataset. A platform (for example Labelbox or Toloka) sells software or crowd access, and your team runs the project. Managed services remove hiring and QA from your plate.
How much do data annotation companies charge?
Few publish prices. Label Your Data states about $6 per annotator hour for time-billed managed projects (Label Your Data pricing page); 7 of the 9 companies we compare publish no prices at all. See our pricing page for the full breakdown, including the difference between what annotators are paid and what clients are charged.
How should I choose a data annotation company?
Match the service model to your team first (managed service vs. platform vs. expert network), then verify four things: the QA process and who checks the checkers, security and data-handling terms in writing, pricing in a comparable unit (per label, per hour, or per project), and a paid pilot on your own data before any volume commitment. Our methodology page lists the full rubric.
Do data annotation companies hire annotators directly?
Many do, and many search results for this term are aimed at people looking for annotation work rather than buying it. This guide is written for buyers. Pay ranges reported for annotators and experts are summarized on our pricing page, with sources.