kitio.aiProlific vs Sigma AI
A side-by-side look at pricing plans, free tiers, features, pros and cons, updated for 2026. Prolific starts at See pricing page and Sigma AI starts at See pricing page. Check both pricing pages for current plans.
At a glance
Best for
Category
Pricing model
Starting price
Free plan
Made by
Based in
Rating
Key features
- Human feedback for AI
- Agentic evals and benchmarks
- Verified participant pool
- Domain expert panels
- Human feedback API
- MCP server
- Training data creation
- Independent model evaluation
- Human review operations
- 700+ languages
- Secure training sandboxes
| Feature | Prolific | Sigma AI |
|---|---|---|
| Best for | Human feedback and study participants for AI training, evals and research | Human-expert data, evaluation and review for AI teams |
| Category | Data & analytics | Data & analytics |
| Pricing model | Paid | Paid |
| Starting price | See pricing page | See pricing page |
| Free plan | No | No |
| Made by | Prolific | Sigma AI |
| Based in | United Kingdom | Spain |
| Rating | No ratings yet | No ratings yet |
| Key features |
|
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Pricing compared
Prolific starts at See pricing page and Sigma AI starts at See pricing page. Check both pricing pages for current plans.
Free plan
Cheapest paid plan
Top plan
Free trial
3 plans
Academic
33.3% platform fee
- For academic and non-profit teams
- Fee on top of participant rewards
Corporate
42.8% platform fee
- For companies
- No contract or subscription
Managed Services
Contact sales
- Expert guidance
- Larger AI data projects
Prices in USD, checked Nov 5, 2026 or later. Plans change often, so confirm on each tool's site before you buy.
Pros and cons
Prolific
- Pay as you go with no contract
- Large verified participant pool
- Discounted fee for academics
- Platform fee adds over 40% for companies
- Participant rewards are paid on top
- Not a self-contained labeling tool
Sigma AI
- Very wide language coverage
- Large pool of vetted experts
- Long track record in AI data
- No self-serve option
- No public pricing
- Aimed at companies building models
Which one should you choose?
Choose Prolific if you want:
- Pay as you go with no contract
- Large verified participant pool
- Discounted fee for academics
Watch out: platform fee adds over 40% for companies.
Choose Sigma AI if you want:
- Very wide language coverage
- Large pool of vetted experts
- Long track record in AI data
Watch out: no self-serve option.
Prolific vs Sigma AI FAQ
What is the difference between Prolific and Sigma AI?
Prolific: Human feedback and study participants for AI training, evals and research. Sigma AI: Human-expert data, evaluation and review for AI teams. Both are data & analytics tools.
Is Prolific or Sigma AI cheaper?
Prolific starts at See pricing page and Sigma AI starts at See pricing page. Check both pricing pages for current plans.
Do Prolific and Sigma AI have free plans?
Prolific: No. Sigma AI: No.
Who makes Prolific?
Prolific is made by Prolific, based in United Kingdom.
Who makes Sigma AI?
Sigma AI is made by Sigma AI, based in Spain.
Which should I choose, Prolific or Sigma AI?
Choose Prolific if you value pay as you go with no contract and large verified participant pool. Choose Sigma AI if you value very wide language coverage and large pool of vetted experts.