Free mortgage calculation API: no authentication, no key, no rate limit
and no signup. HTTPS and CORS confirmed against the live endpoint from a
third-party origin.
Endpoints cover monthly payment and amortization, affordability,
refinance break-even, closing costs, PMI and MIP, and property tax
reference data for all fifty states. The state data is also published
under CC BY 4.0.
Checked before opening: no mortgage or amortization API is currently
listed, the entry is alphabetical between Twelve Data and VAT
Validation, and the description is 76 characters.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011WY6ZEBhp1yhG6ktdHHEv3
