The dated diff history is litigation / audit evidence: an appeal firm, permit expediter or refund shop pays because they cannot reconstruct an overwritten fee. Each observation is SHA-256 hashed; pairs with signed agent-receipts provenance.
GET /api/diffs — global change feed (preview).GET /api/field/<id> — per-field current value + change-log preview + latest alert.GET /api/catalog — every tracked field + source URL.| Tool | Price | What you get |
|---|---|---|
fee_history_full | $0.20 | Full signed append-only history for one tracked fee/rate field: every hashed dated observation + every change-diff. The evidence record for what a fee was on a date the agency has since overwritten. $0.20 / field. |
diff_feed_full | $0.10 | Full global change feed across all tracked jurisdictions (not the truncated preview) — every fee/rate that moved with from/to/date. $0.10. |
Discovery: /.well-known/x402 · /llms.txt · pay challenge at POST /x402/pay. Settlement wallet is receive-only.