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Medicare Part D Formulary & Plan Change Feed
x402
Medicare Part D Formulary & Plan Change Feed is a paid API for AI agents from data.spencermcw.com, paid per call via x402, $0.05/call, status unknown (last checked 2026-10-23).
Returns a paginated feed of Medicare Part D formulary and plan changes detected monthly from CMS data, including drug additions/removals, tier changes, prior-auth, step-therapy, quantity-limit, and premium changes.
Price / call$0.05
Success—
StatusUnknown
How this service works
Which Medicare Part D formularies changed this month? Drugs added or dropped, tier, prior-authorization, step-therapy and quantity-limit changes and plan premium changes, computed by Distill from CMS’s monthly formulary files. Updated monthly. $0.05 per call (x402, USDC on Base); 3 free calls a day.
Output
A paginated array of change records, each containing: a unique change ID, plan year, release date, entity type (formulary or plan), a key identifying the specific drug (RxCUI) or plan (contract-plan-segment), the field that changed (e.g. tier, prior_auth, premium), old and new values, detection timestamp, method version, and SHA256 hashes of the source CMS files used for comparison. Also includes a next_cursor for pagination.
Example use cases
Monthly formulary change monitoring
“Pull the latest Medicare Part D formulary changes from this month — I need to know which drugs had tier changes, prior-authorization requirements added, or were dropped entirely from coverage.”
Medicare plan premium change tracking
“Show me any Medicare Part D plan-level changes detected since March 1, 2025, specifically looking for premium or cost-sharing updates — up to 100 records please.”
Drug coverage change alert for a specific formulary
“What changes were made in the 2025 plan year for Medicare Part D formularies? Filter for formulary entity type and give me the most recent 25 changes with their old and new values.”
Technical details
Endpoint
GEThttps://data.spencermcw.com/v1/medicare/partd/changes?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to track month-over-month changes in Medicare Part D formularies or plan attributes derived directly from CMS official monthly files. It is ideal for compliance monitoring, beneficiary advocacy tools, pharmacy benefit analysis, or any workflow that needs auditable change history with source file hashes. Prefer it over manually diffing CMS files or scraping plan websites.
Side effects
- Invalid since datetime format returns 400 validation error
- Cursor value out of range or malformed returns 400
- Plan year outside valid range (2000-2100) returns 400
- Exceeding 3 free daily calls without payment returns 402 Payment Required
- Invalid entity enum value (not formulary or plan) returns 400
- No changes found for specified filters returns empty records array
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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