_{Pair drilldown in the web workbench: cluster members, field-level diff, and a one-line NL explanation per pair. pip install goldenmatch[web] then goldenmatch serve-ui <project>. More screenshots →}

v3.17.1: The polars-free first run actually works now. 3.17.0 claimed this and did not deliver it: auto-config puts negative evidence on the exact matchkey by default, and that path still bridged to polars, so goldenmatch dedupe customers.csv exited 3 on a default install. Verified the way it should have been the first time -- pip install into a clean polars-free venv, then the documented command.

v3.17.0: The documented first run works on a default install. pip install goldenmatch followed by goldenmatch dedupe customers.csv -- the quickstart on every doc surface -- exited 3 on a polars-free install, which is what a plain install has produced since polars became an optional extra. Three separate polars imports on the zero-config path (auto-config ingest, the Arrow lane's preflight decline, and the csv writer) are gone, with polars' exact csv bytes reproduced and parity-pinned.

v3.13.0: Fellegi-Sunter training runs distributed on Spark. The E-step reads only the comparison vector, so identical vectors collapse to one counted row and the whole step becomes a Spark GROUP BY over agreement patterns -- the cluster counts, the driver only fits. Training cost tracks DISTINCT vectors (bounded by prod(levels + 1)), not pairs: 1M -> 5M rows grew candidate pairs 5.00x and the distributed counting stage 5.25x, while distinct patterns grew 3.0% (433 -> 446) and driver-side EM stayed at 0.01s. Runs on jar-only executors via goldenmatch-spark, off the same Rust kernel every other surface uses.

What you get: the golden entity

Most entity-resolution tools hand you clusters and stop. GoldenMatch keeps going: it resolves messy records into a durable golden entity, one per real-world customer, that survives re-runs, carries provenance on every field, and answers "who is this, and where did each value come from?" in a single call.

• A stable identity, not a throwaway cluster id. Every entity gets a stable entity_id (UUIDv7) that persists across runs as new data arrives. Records are absorbed, entities merge or split, but the id an entity earns is the id downstream systems can rely on. Run-local cluster numbers reshuffle on every run; these don't.
• Whole-record provenance. Every field of the golden record traces back to the source record that won it: which source, when it was last seen, and which survivorship strategy picked it. The values it didn't pick stay visible rather than being silently dropped. Provenance is on the whole unified record, not just the match decision.
• Governed by construction. Conflicting values collapse to one best value by an explicit survivorship policy (most-complete · source-priority · most-recent · majority-vote); every identity change lands in an append-only event timeline; and the log is sealed with a hash-chained, tamper-evident audit that a reviewer (or the other language port) can independently verify.

customer_360(entity_id) composes it into one read: golden record, per-field provenance, every linked source record, the event timeline, and the entity's relationship neighborhood:

// customer_360("018f...c2a1")  (trimmed)
{
  "entity_id": "018f2b7e-...-c2a1", "confidence": 0.97, "record_count": 3,
  "sources": ["salesforce", "billing", "support"],
  "golden_record": { "name": "Ada Lovelace", "email": "ada@analytical.io", "phone": "+1-555-0100" },
  "field_provenance": [
    { "field": "email", "value": "ada@analytical.io",
      "winning_source": "billing", "winning_record_id": "billing:8821",
      "conflicting_values": [ { "value": "ada@ada.dev", "source": "salesforce" } ] },
    { "field": "phone", "value": "+1-555-0100", "winning_source": "salesforce" }
  ],
  "timeline": [ { "kind": "created", "actor": "pipeline", "recorded_at": "2026-07-30T..." },
                { "kind": "absorbed_record", "reason": "matched billing:8821" } ],
  "relationships": [ { "other_entity_id": "018f...9d0e", "kind": "shares_address" } ]
}