Medicare Physician Fee Schedule Change Feed

Choose this endpoint when you need a structured, auditable diff of CMS Medicare Physician Fee Schedule data between quarterly releases — covering RVU, conversion factor, GPCI, locality, or OPPS-cap fields — rather than querying the raw CMS RVU files yourself or using a general Medicare fee lookup. It is especially valuable for billing compliance, reimbursement monitoring, or change-detection workflows where you need to know exactly what changed, when it changed, and from what value to what value, with provenance via SHA-256 source hashes.

• Invalid code format (must match ^[0-9A-Za-z]{5}$) returns validation error
• Invalid release format (must match ^\d{4}[A-Da-d]$) returns validation error
• Invalid since datetime format returns schema validation error
• Invalid cursor format returns error
• Limit out of range (must be 1–100) returns validation error
• Payment not provided or insufficient USDC on Base triggers x402 payment required response after 3 free daily calls
• No matching change records returns empty records array
• Rate limiting if free call quota exceeded without payment