Public API

Base URL + key

The ledger runs on Supabase, which auto-generates a PostgREST API. The publishable key is safe to embed in clients — RLS policies are the actual authorization layer.

BASE = https://gtljxjjmacbokpjsfyql.supabase.co/rest/v1
KEY  = sb_publishable_aFHhciBm6e8Z2W_7TCvl9g_wfWCiqr6

Send the key as apikey + Authorization: Bearer … on every request.

What anonymous clients can read

• calculations — every published calculation (id, name, jurisdiction, schemas).
• rules — only rows where status is active or superseded.
• facts — only rows where status is active, superseded, stale, or drift_detected. Pre-verification (proposed) and retracted facts are not visible to anon.
• sources — non-retired source URLs with publisher and authority tier.
• rule_facts — the rule→fact junction with role labels.

Examples

List all calculations

curl -s "https://gtljxjjmacbokpjsfyql.supabase.co/rest/v1/calculations?select=id,name,jurisdiction" \
  -H "apikey: sb_publishable_aFHhciBm6e8Z2W_7TCvl9g_wfWCiqr6" \
  -H "Authorization: Bearer sb_publishable_aFHhciBm6e8Z2W_7TCvl9g_wfWCiqr6"

Fetch a specific calculation

curl -s "https://gtljxjjmacbokpjsfyql.supabase.co/rest/v1/calculations?id=eq.calc_il_state_withholding_owed&select=*" \
  -H "apikey: sb_publishable_aFHhciBm6e8Z2W_7TCvl9g_wfWCiqr6" \
  -H "Authorization: Bearer sb_publishable_aFHhciBm6e8Z2W_7TCvl9g_wfWCiqr6"

Walk a lineage chain (calc → rule → facts → sources)

# Get the rule's facts via the rule_facts junction — joins are server-side
curl -s "https://gtljxjjmacbokpjsfyql.supabase.co/rest/v1/rule_facts?rule_id=eq.rule_il_state_withholding_optional_2026&select=fact_id,role,facts(id,claim_summary,source_quote,source_id,sources(url,publisher))" \
  -H "apikey: sb_publishable_aFHhciBm6e8Z2W_7TCvl9g_wfWCiqr6" \
  -H "Authorization: Bearer sb_publishable_aFHhciBm6e8Z2W_7TCvl9g_wfWCiqr6"

PostgREST resource embedding does the joins server-side. One request returns the full lineage.

List facts by jurisdiction

curl -s "https://gtljxjjmacbokpjsfyql.supabase.co/rest/v1/facts?jurisdiction=eq.state:IL&select=id,claim_summary,status,verified_at" \
  -H "apikey: sb_publishable_aFHhciBm6e8Z2W_7TCvl9g_wfWCiqr6" \
  -H "Authorization: Bearer sb_publishable_aFHhciBm6e8Z2W_7TCvl9g_wfWCiqr6"

Verifying a fact yourself

Every fact carries source_quote (the verbatim text on the page at verification time) and source_hash_at_verify (a SHA-256 of the page bytes). To verify a fact independently:

FACT_URL=$(curl -s "https://gtljxjjmacbokpjsfyql.supabase.co/rest/v1/facts?id=eq.fact_idor_2026_il_flat_income_tax_rate&select=sources(url)" \
  -H "apikey: sb_publishable_aFHhciBm6e8Z2W_7TCvl9g_wfWCiqr6" -H "Authorization: Bearer sb_publishable_aFHhciBm6e8Z2W_7TCvl9g_wfWCiqr6" | jq -r '.[0].sources.url')

curl -s "$FACT_URL" | sha256sum

Compare the result against source_hash_at_verify. If it matches, the page hasn't moved since verification. If it doesn't, the corresponding fact would already be marked drift_detected by the nightly drift cron.

Rate limiting

Standard Supabase fair-use applies. Heavy programmatic use should self-throttle to a few requests per second. If you need bulk access, get in touch.

MCP server (planned)

An MCP server wrapping these endpoints as agent-callable tools is in design. Tools under consideration:

• compliance_ledger.list_calculations(jurisdiction?)
• compliance_ledger.get_lineage(calculation_id)
• compliance_ledger.verify_fact(fact_id) — re-fetches the source and compares against the stored hash, returning a fresh integrity result.
• compliance_ledger.search_facts(query, jurisdiction?, status?)
• compliance_ledger.resolve_zone(payer_kind, payee_kind, jurisdiction, taxpayer_attrs, gross_per_period) — the same call the tool makes; returns lines + citations.

If you'd like to be a design partner on the MCP shape, get in touch via kelmen.space.