Real changes on the pages seeded into the shared corpus — no signup, no key, no sales page in between. This is the same data the API and the MCP server hand your agent, rendered.
Read it yourself instead:
curl -s https://sincewhen.dev/api/demo/changes
One call gets you an account and a key. Free is 5 pages, checked daily, diffs kept 30 days — check the pricing before you assume daily is enough for what you need.
curl -X POST https://sincewhen.dev/api/auth/signup \
-H "Content-Type: application/json" \
-d '{"email":"you@example.com","password":"at least 10 chars","create_api_key":true}'
Then point your agent at it — per-client MCP setup.