CHEESE APISearch

Default structural search

Recommended SynthonOR proposal with exact ECFP4/Tanimoto product reranking.

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POST /api/v2/search is the recommended starting point. It uses Morgan-OR over synthons to propose constructible products, assembles them, then ranks exact product ECFP4 fingerprints by Tanimoto. There is no scorer field: this route has one stable scientific meaning.

{
  "query_smiles": "CCO",
  "database_id": "enamine-real-v5a",
  "limit": 20
}
FieldMeaning
query_smilesRequired structure, at most 2,048 characters
database_idRequired chemical-space ID from the catalog
limitFinal products, default 20, range 1–200
shortlist_multiplierAdvanced proposal/recall budget, default 10, range 0–200; 0 disables candidate over-fetch
include_synthonsOpt-in route/synthon expansion; increases response size

Increasing shortlist_multiplier asks the engine to assemble and exactly rerank more proposals. It can improve recall at a proportional latency/cost increase; it does not change the final metric.

Set shortlist_multiplier to 0 for explicit no-over-fetch mode. The engine proposes exactly limit products and still applies exact assembled-product ECFP4/Tanimoto scoring. This is not a proposal-only mode and does not weaken the endpoint's stated metric.

The request is safe to retry against the same pinned release. A 429 is transient and includes Retry-After; validation and invalid-SMILES errors are not retryable. See the quickstart for curl, Python, CLI, and a representative response.