Developers

Tax Lien Data API

Query US tax lien and tax deed auction data programmatically: state statutory terms with a composite TLS Index Score, county competition/saturation scores, and parcel-level auction inventory. Responses are JSON (CSV available on parcels). Aggregate endpoints are public; parcel data requires an API key available on the Unlimited plan.

Authentication

Generate a key from your API Keys page (Unlimited members). Send it as a bearer token or a query parameter. Keys are hashed at rest and shown once.

curl -H "Authorization: Bearer tls_live_xxx" \
  "https://taxliensimple.com/api/v1/parcels?state=Texas&county=Travis"

# or
curl "https://taxliensimple.com/api/v1/parcels?state=Texas&api_key=tls_live_xxx"

Rate limits

Keyed requests are limited per key (default 1,000 requests/hour). Every response includesX-RateLimit-Limit,X-RateLimit-Remaining andX-RateLimit-Reset. Exceeding the limit returns HTTP 429.

Endpoints

GET/api/v1/statesPublic

All 51 jurisdictions with statutory terms (system, max rate, redemption period, statute citation, official source) and a 0–100 TLS Index Score composite.

curl "https://taxliensimple.com/api/v1/states"

Returns: state, slug, system, investor_accessible, max_rate, penalty_or_interest, redemption_period, auction_format, auction_schedule, statute_citation, official_source_url, online_portals, tls_index_score, verified, verified_date.

GET/api/v1/countiesPublic

County competition/saturation data. Optional ?state= filter. Aggregate only — no parcel PII.

curl "https://taxliensimple.com/api/v1/counties?state=Texas"

Returns: state, county, competition_score, competition_band, online_auctions, parcels, lien_share, computed_at. Competition is a saturation proxy, not a measured realized rate.

GET/api/v1/parcelsAPI key (Unlimited)

Parcel-level auction inventory. Requires a valid key (401 without). Never exposes owner names or contact data.

Params: state, county, family (lien | deed | foreclosure), format (json | csv), limit (1–500, default 100), offset.

curl -H "Authorization: Bearer tls_live_xxx" \
  "https://taxliensimple.com/api/v1/parcels?state=Texas&family=lien&format=csv"

Returns per parcel: id, state, county, auction_date, parcel_number, situs_address, property_type, opening_bid, assessed_value, back_tax_total, tax_year, redemption_window_months, lien_to_value_ratio, competition_score, enrichment_status, source_url, status. Fields like surviving liens, occupancy and market value are not included — verify independently.

Plans

  • • Public — /states and /counties aggregate endpoints, no key required.
  • • Unlimited — API keys for parcel-level access. See pricing →

Data is provided for research and is not legal, tax, or investment advice. Statutory terms are educational summaries; always confirm current statutes with the official source. The TLS Index Score and county competition scores are research aids, not recommendations or guarantees of yield.