Summary
This is your reference for adding Internet Identity authentication to ICP apps. It covers passkey and OpenID sign-in flows, delegation handling, and principal-per-app isolation. The bulk of the value is in the "Mistakes That Break Your Build" section, which walks through the twelve ways developers typically break II integration: wrong URLs, missing /authorize paths, bad nonce handling, and skipping signer verification when reading attributes. The local dev setup is straightforward since icp-cli 0.2.4, mainnet II just works against your local replica without extra config. If you're adding login to a frontend or need to understand how attribute bundles work on the backend, this covers it.
Install to Claude Code
npx -y skills add dfinity/icskills --skill internet-identity --agent claude-codeInstalls into .claude/skills of the current project.
Keep your Mac awake while Claude Code and 40+ AI agents run. Sleeps when they're idle.
One time payment $9 →
Integrate web data into your AI product. One API to scrape website & brand data.
Get API Key Now →
Agent, run crypto. Access onchain data & trade routes via 1inch.
Install now →
On Capafy, your Skill runs online 24/7 as an agent product, and you get paid every time someone uses it.
Start earning →
Files
SKILL.md
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Featured
Keep your Mac awake while Claude Code and 40+ AI agents run. Sleeps when they're idle.
One time payment $9 →Integrate web data into your AI product. One API to scrape website & brand data.
Get API Key Now →Agent, run crypto. Access onchain data & trade routes via 1inch.
Install now →On Capafy, your Skill runs online 24/7 as an agent product, and you get paid every time someone uses it.
Start earning →First SeenJun 3, 2026
