World Developer Docs

The World stack is a privacy-preserving trust layer for companies that need to know whether a real, unique, present, or eligible person is behind an action.

Start with the trust question you need to answer

Question	Use	What it helps you do
Who can participate?	World ID	Prove a user is a real, unique human.
Who is present right now?	Selfie Check	Confirm that a human is approving an important action.
Who meets the requirements?	Identity Check (Preview)	Verify supported document-checked attributes without collecting the underlying document.
When can an agent act?	AgentKit	Let an AI agent act after the required human trust checks are satisfied.

Why companies use World ID

Stop bots and duplicate accounts. Make rewards, referrals, voting, reviews, promotions, and social participation one-person-one-action.
Protect sensitive moments. Add human presence when someone approves a payment, recovers an account, deploys software, or authorizes a high-risk transaction.
Check eligibility privately. Confirm that someone meets a policy without asking your product to store their full identity documents.
Match trust to risk. Start with a lightweight check, then require stronger proof of humanity, presence, or eligibility where the stakes are higher.
Build safer AI products. Distinguish people from agents and make human approval an explicit boundary for consequential actions.
Make communities more accountable. Reduce impersonation, fake accounts, reputation manipulation, and fraudulent content while preserving privacy.

Where it fits in YC startups

If you’re building…	The simplest place to use World ID
Proving you’re human	Require one human per account to reduce Sybil attacks.
An AI consumer product	Protect a free trial, referral, reward, or limited promotion from duplicate claims.
Multiplayer AI	Distinguish verified people from AI agents in a shared environment.
An operating system for the physical world	Make sure tasks are assigned to real, unique workers.
A real-world data product	Limit data contribution and rewards to one unique contributor.
AI-native compliance	Add a privacy-preserving proof that a user is a real human before a regulated or high-risk action.
Crypto or stablecoins	Run fair allocations, grants, governance, airdrops, or incentives.
Cloud tools for small software	Reduce fake workspaces, spam, and abuse before privileged access.
Education	Protect scholarships, subsidized access, rewards, and student benefits.
Products for the aging population	Reduce impersonation of patients, family members, and caregivers.
Self-maintaining APIs	Add human accountability before critical code changes, merges, or deployments.
Defense or physical infrastructure	Add a human trust signal to safety-critical operations.

Ready to build?

Start integrating World ID to bring the right trust signal into your product.

Overview

IDKit

Sandbox

Credentials

Migration

Technical Reference

World ID for YC Startups

Start with the trust question you need to answer

Why companies use World ID

Where it fits in YC startups

Ready to build?

​Start with the trust question you need to answer

​Why companies use World ID

​Where it fits in YC startups

​Ready to build?

Start with the trust question you need to answer

Why companies use World ID

Where it fits in YC startups

Ready to build?