System
Prompt
Context
streaming, per model
Sonnet only · Haiku ignores it
Your key stays in your browser. It is saved in this browser's
Because the calls run in the browser, the key is readable by anything else running on this page. Use a key you can rotate, not a production one. Clear wipes it from storage. Prefer to run it on your own machine? Save this page — it is one self-contained file with no build step, and it works from any static server.
localStorage and sent only to api.anthropic.com. This page has no
server and no analytics on the key — nothing is logged here, and every call is billed to your
own Anthropic account.
Because the calls run in the browser, the key is readable by anything else running on this page. Use a key you can rotate, not a production one. Clear wipes it from storage. Prefer to run it on your own machine? Save this page — it is one self-contained file with no build step, and it works from any static server.