## Estimate Cost

`client.SmallMolecule.Design.EstimateCost(ctx, body) (*SmallMoleculeDesignEstimateCostResponse, error)`

**post** `/compute/v1/small-molecule/design/estimate-cost`

Estimate the billed cost of a small molecule design run without creating any resource or consuming GPU. Includes the SynFlowNet generation charges implied by the scheduler iteration cap plus Boltz2 scoring for each requested molecule.

### Parameters

- `body SmallMoleculeDesignEstimateCostParams`

  - `NumMolecules param.Field[int64]`

    Number of molecules to generate. Must be between 10 and 1,000,000.

  - `Target param.Field[SmallMoleculeDesignEstimateCostParamsTarget]`

    Target protein with binding pocket for small molecule design or screening

    - `Entities []SmallMoleculeDesignEstimateCostParamsTargetEntity`

      Protein entities defining the target structure. Each entity represents a protein chain.

      - `ChainIDs []string`

        Chain IDs for this entity

      - `Type Protein`

        - `const ProteinProtein Protein = "protein"`

      - `Value string`

        Amino acid sequence (one-letter codes)

      - `Cyclic bool`

        Whether the sequence is cyclic

      - `Modifications []SmallMoleculeDesignEstimateCostParamsTargetEntityModificationUnion`

        Post-translational modifications. Optional; defaults to an empty list when omitted.

        - `type SmallMoleculeDesignEstimateCostParamsTargetEntityModificationCcdModification struct{…}`

          - `ResidueIndex int64`

            0-based index of the residue to modify

          - `Type Ccd`

            - `const CcdCcd Ccd = "ccd"`

          - `Value string`

            CCD code from RCSB PDB (e.g. 'MSE' for selenomethionine, 'SEP' for phosphoserine)

        - `type SmallMoleculeDesignEstimateCostParamsTargetEntityModificationSmilesModification struct{…}`

          - `ResidueIndex int64`

            0-based index of the residue to modify

          - `Type Smiles`

            - `const SmilesSmiles Smiles = "smiles"`

          - `Value string`

            SMILES string for the modification

    - `Bonds []SmallMoleculeDesignEstimateCostParamsTargetBond`

      Covalent bond constraints between atoms in the target complex. Atom-level ligand references currently support ligand_ccd only; ligand_smiles is unsupported.

      - `Atom1 SmallMoleculeDesignEstimateCostParamsTargetBondAtom1Union`

        Ligand atom reference. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

        - `type SmallMoleculeDesignEstimateCostParamsTargetBondAtom1LigandAtom struct{…}`

          Ligand atom reference. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

          - `AtomName string`

            Standardized atom name (verifiable in CIF file on RCSB). Atom-level references to ligand_smiles entities are currently unsupported; use ligand_ccd instead.

          - `ChainID string`

            Chain ID containing the atom

          - `Type LigandAtom`

            - `const LigandAtomLigandAtom LigandAtom = "ligand_atom"`

        - `type SmallMoleculeDesignEstimateCostParamsTargetBondAtom1PolymerAtom struct{…}`

          - `AtomName string`

            Standardized atom name (verifiable in CIF file on RCSB)

          - `ChainID string`

            Chain ID containing the atom

          - `ResidueIndex int64`

            0-based residue index

          - `Type PolymerAtom`

            - `const PolymerAtomPolymerAtom PolymerAtom = "polymer_atom"`

      - `Atom2 SmallMoleculeDesignEstimateCostParamsTargetBondAtom2Union`

        Ligand atom reference. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

        - `type SmallMoleculeDesignEstimateCostParamsTargetBondAtom2LigandAtom struct{…}`

          Ligand atom reference. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

          - `AtomName string`

            Standardized atom name (verifiable in CIF file on RCSB). Atom-level references to ligand_smiles entities are currently unsupported; use ligand_ccd instead.

          - `ChainID string`

            Chain ID containing the atom

          - `Type LigandAtom`

            - `const LigandAtomLigandAtom LigandAtom = "ligand_atom"`

        - `type SmallMoleculeDesignEstimateCostParamsTargetBondAtom2PolymerAtom struct{…}`

          - `AtomName string`

            Standardized atom name (verifiable in CIF file on RCSB)

          - `ChainID string`

            Chain ID containing the atom

          - `ResidueIndex int64`

            0-based residue index

          - `Type PolymerAtom`

            - `const PolymerAtomPolymerAtom PolymerAtom = "polymer_atom"`

    - `Constraints []SmallMoleculeDesignEstimateCostParamsTargetConstraintUnion`

      Structural constraints (pocket and contact). Atom-level ligand references currently support ligand_ccd only; ligand_smiles is unsupported.

      - `type SmallMoleculeDesignEstimateCostParamsTargetConstraintPocketConstraint struct{…}`

        Constrains the binder to interact with specific pocket residues on the target.

        - `BinderChainID string`

          Chain ID of the binder molecule

        - `ContactResidues map[string, []int64]`

          Binding pocket residues keyed by chain ID. Each key is a chain ID (e.g. "A") and the value is an array of 0-indexed residue indices that define the pocket on that chain.

        - `MaxDistanceAngstrom float64`

          Maximum allowed distance in Angstroms between binder and pocket residues. Typical range: 4-8 A.

        - `Type Pocket`

          - `const PocketPocket Pocket = "pocket"`

        - `Force bool`

          Whether to force the constraint

      - `type SmallMoleculeDesignEstimateCostParamsTargetConstraintContactConstraint struct{…}`

        Contact constraint between two tokens. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

        - `MaxDistanceAngstrom float64`

          Maximum distance in Angstroms

        - `Token1 SmallMoleculeDesignEstimateCostParamsTargetConstraintContactConstraintToken1Union`

          Ligand contact token. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

          - `type SmallMoleculeDesignEstimateCostParamsTargetConstraintContactConstraintToken1PolymerContactToken struct{…}`

            - `ChainID string`

              Chain ID

            - `ResidueIndex int64`

              0-based residue index

            - `Type PolymerContact`

              - `const PolymerContactPolymerContact PolymerContact = "polymer_contact"`

          - `type SmallMoleculeDesignEstimateCostParamsTargetConstraintContactConstraintToken1LigandContactToken struct{…}`

            Ligand contact token. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

            - `AtomName string`

              Atom name. Atom-level references to ligand_smiles entities are currently unsupported; use ligand_ccd instead.

            - `ChainID string`

              Chain ID

            - `Type LigandContact`

              - `const LigandContactLigandContact LigandContact = "ligand_contact"`

        - `Token2 SmallMoleculeDesignEstimateCostParamsTargetConstraintContactConstraintToken2Union`

          Ligand contact token. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

          - `type SmallMoleculeDesignEstimateCostParamsTargetConstraintContactConstraintToken2PolymerContactToken struct{…}`

            - `ChainID string`

              Chain ID

            - `ResidueIndex int64`

              0-based residue index

            - `Type PolymerContact`

              - `const PolymerContactPolymerContact PolymerContact = "polymer_contact"`

          - `type SmallMoleculeDesignEstimateCostParamsTargetConstraintContactConstraintToken2LigandContactToken struct{…}`

            Ligand contact token. Atom-level ligand references currently support ligand_ccd entities only; ligand_smiles is unsupported.

            - `AtomName string`

              Atom name. Atom-level references to ligand_smiles entities are currently unsupported; use ligand_ccd instead.

            - `ChainID string`

              Chain ID

            - `Type LigandContact`

              - `const LigandContactLigandContact LigandContact = "ligand_contact"`

        - `Type Contact`

          - `const ContactContact Contact = "contact"`

        - `Force bool`

          Whether to force the constraint

    - `PocketResidues map[string, []int64]`

      Binding pocket residues, keyed by chain ID. Each key is a chain ID (e.g. "A") and the value is an array of 0-indexed residue indices that define the binding pocket on that chain. When provided, these residues guide pocket extraction and add a derived pocket constraint during affinity predictions. That derived constraint remains separate from any explicit pocket constraints in target.constraints. When omitted, the model auto-detects the pocket.

    - `ReferenceLigands []string`

      Reference ligands as SMILES strings that help the model identify the binding pocket. When omitted, a set of drug-like default ligands is used for pocket detection.

  - `ChemicalSpace param.Field[SmallMoleculeDesignEstimateCostParamsChemicalSpace]`

    Chemical space to constrain generated molecules. Currently only 'enamine_real' (Enamine REAL chemical space) is supported. Additional options may be added in the future.

    - `const SmallMoleculeDesignEstimateCostParamsChemicalSpaceEnamineReal SmallMoleculeDesignEstimateCostParamsChemicalSpace = "enamine_real"`

  - `IdempotencyKey param.Field[string]`

    Client-provided key to prevent duplicate submissions on retries

  - `MoleculeFilters param.Field[SmallMoleculeDesignEstimateCostParamsMoleculeFilters]`

    Molecule filtering configuration. Controls both Boltz built-in SMARTS filtering and custom filters.

    - `BoltzSmartsCatalogFilterLevel SmallMoleculeDesignEstimateCostParamsMoleculeFiltersBoltzSmartsCatalogFilterLevel`

      Controls the stringency of Boltz's built-in SMARTS structural alert filtering, which removes molecules matching known problematic substructures. 'recommended' (default): applies a curated set of alerts balancing safety and hit rate. 'extra': adds additional alerts beyond the recommended set for stricter filtering. 'aggressive': applies the most comprehensive alert set — may reject viable molecules. 'disabled': turns off Boltz SMARTS filtering entirely; only custom_filters will be applied.

      - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersBoltzSmartsCatalogFilterLevelRecommended SmallMoleculeDesignEstimateCostParamsMoleculeFiltersBoltzSmartsCatalogFilterLevel = "recommended"`

      - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersBoltzSmartsCatalogFilterLevelExtra SmallMoleculeDesignEstimateCostParamsMoleculeFiltersBoltzSmartsCatalogFilterLevel = "extra"`

      - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersBoltzSmartsCatalogFilterLevelAggressive SmallMoleculeDesignEstimateCostParamsMoleculeFiltersBoltzSmartsCatalogFilterLevel = "aggressive"`

      - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersBoltzSmartsCatalogFilterLevelDisabled SmallMoleculeDesignEstimateCostParamsMoleculeFiltersBoltzSmartsCatalogFilterLevel = "disabled"`

    - `CustomFilters []SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterUnion`

      Custom filters to apply. Molecules must pass all filters (AND logic).

      - `type SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterLipinskiFilter struct{…}`

        Lipinski's Rule of Five filter. Rejects molecules that violate drug-likeness criteria based on molecular weight, LogP, hydrogen bond donors, and hydrogen bond acceptors.

        - `MaxHba float64`

          Maximum number of hydrogen bond acceptors. Lipinski threshold: 10

        - `MaxHbd float64`

          Maximum number of hydrogen bond donors. Lipinski threshold: 5

        - `MaxLogp float64`

          Maximum LogP. Lipinski threshold: 5

        - `MaxMw float64`

          Maximum molecular weight (Da). Lipinski threshold: 500

        - `Type LipinskiFilter`

          - `const LipinskiFilterLipinskiFilter LipinskiFilter = "lipinski_filter"`

        - `AllowSingleViolation bool`

          If true, one rule violation is allowed (classic Rule of Five). Defaults to false (all rules must pass).

      - `type SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterRdkitDescriptorFilter struct{…}`

        Filter molecules by RDKit molecular descriptors. Each descriptor is constrained to a min/max range. Only descriptors you provide are checked — omitted descriptors are unconstrained.

        - `Type RdkitDescriptorFilter`

          - `const RdkitDescriptorFilterRdkitDescriptorFilter RdkitDescriptorFilter = "rdkit_descriptor_filter"`

        - `FractionCsp3 SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterRdkitDescriptorFilterFractionCsp3`

          Min/max range constraint for an RDKit molecular descriptor

          - `Max float64`

            Maximum allowed value (inclusive)

          - `Min float64`

            Minimum allowed value (inclusive)

        - `MolLogp SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterRdkitDescriptorFilterMolLogp`

          Min/max range constraint for an RDKit molecular descriptor

          - `Max float64`

            Maximum allowed value (inclusive)

          - `Min float64`

            Minimum allowed value (inclusive)

        - `MolWt SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterRdkitDescriptorFilterMolWt`

          Min/max range constraint for an RDKit molecular descriptor

          - `Max float64`

            Maximum allowed value (inclusive)

          - `Min float64`

            Minimum allowed value (inclusive)

        - `NumAromaticRings SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterRdkitDescriptorFilterNumAromaticRings`

          Min/max range constraint for an RDKit molecular descriptor

          - `Max float64`

            Maximum allowed value (inclusive)

          - `Min float64`

            Minimum allowed value (inclusive)

        - `NumHAcceptors SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterRdkitDescriptorFilterNumHAcceptors`

          Min/max range constraint for an RDKit molecular descriptor

          - `Max float64`

            Maximum allowed value (inclusive)

          - `Min float64`

            Minimum allowed value (inclusive)

        - `NumHDonors SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterRdkitDescriptorFilterNumHDonors`

          Min/max range constraint for an RDKit molecular descriptor

          - `Max float64`

            Maximum allowed value (inclusive)

          - `Min float64`

            Minimum allowed value (inclusive)

        - `NumHeteroatoms SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterRdkitDescriptorFilterNumHeteroatoms`

          Min/max range constraint for an RDKit molecular descriptor

          - `Max float64`

            Maximum allowed value (inclusive)

          - `Min float64`

            Minimum allowed value (inclusive)

        - `NumRings SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterRdkitDescriptorFilterNumRings`

          Min/max range constraint for an RDKit molecular descriptor

          - `Max float64`

            Maximum allowed value (inclusive)

          - `Min float64`

            Minimum allowed value (inclusive)

        - `NumRotatableBonds SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterRdkitDescriptorFilterNumRotatableBonds`

          Min/max range constraint for an RDKit molecular descriptor

          - `Max float64`

            Maximum allowed value (inclusive)

          - `Min float64`

            Minimum allowed value (inclusive)

        - `Tpsa SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterRdkitDescriptorFilterTpsa`

          Min/max range constraint for an RDKit molecular descriptor

          - `Max float64`

            Maximum allowed value (inclusive)

          - `Min float64`

            Minimum allowed value (inclusive)

      - `type SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCustomFilter struct{…}`

        Filter molecules by custom SMARTS patterns. Molecules matching any pattern are rejected.

        - `Patterns []string`

          SMARTS patterns. Molecules matching any pattern are rejected.

        - `Type SmartsCustomFilter`

          - `const SmartsCustomFilterSmartsCustomFilter SmartsCustomFilter = "smarts_custom_filter"`

      - `type SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilter struct{…}`

        Filter molecules using a predefined SMARTS catalog of structural alerts.

        - `Catalog SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalog`

          Predefined SMARTS catalog to apply. PAINS, BRENK, ChEMBL, and NIH catalogs reject known problematic substructures.

          - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalogPains SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalog = "PAINS"`

          - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalogPainsA SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalog = "PAINS_A"`

          - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalogPainsB SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalog = "PAINS_B"`

          - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalogPainsC SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalog = "PAINS_C"`

          - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalogBrenk SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalog = "BRENK"`

          - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalogChembl SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalog = "CHEMBL"`

          - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalogChemblBms SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalog = "CHEMBL_BMS"`

          - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalogChemblDundee SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalog = "CHEMBL_Dundee"`

          - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalogChemblGlaxo SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalog = "CHEMBL_Glaxo"`

          - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalogChemblInpharmatica SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalog = "CHEMBL_Inpharmatica"`

          - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalogChemblLint SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalog = "CHEMBL_LINT"`

          - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalogChemblMlsmr SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalog = "CHEMBL_MLSMR"`

          - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalogChemblSureChEmbl SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalog = "CHEMBL_SureChEMBL"`

          - `const SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalogNih SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmartsCatalogFilterCatalog = "NIH"`

        - `Type SmartsCatalogFilter`

          - `const SmartsCatalogFilterSmartsCatalogFilter SmartsCatalogFilter = "smarts_catalog_filter"`

      - `type SmallMoleculeDesignEstimateCostParamsMoleculeFiltersCustomFilterSmilesRegexFilter struct{…}`

        Filter molecules by regex patterns on their SMILES representation.

        - `Patterns []string`

          Regex patterns applied to SMILES strings. Molecules matching any pattern are rejected.

        - `Type SmilesRegexFilter`

          - `const SmilesRegexFilterSmilesRegexFilter SmilesRegexFilter = "smiles_regex_filter"`

  - `WorkspaceID param.Field[string]`

    Target workspace ID (admin keys only; ignored for workspace keys)

### Returns

- `type SmallMoleculeDesignEstimateCostResponse struct{…}`

  Estimate response with monetary values encoded as decimal strings to preserve precision.

  - `Breakdown SmallMoleculeDesignEstimateCostResponseBreakdown`

    Cost breakdown for the billed application.

    - `Application SmallMoleculeDesignEstimateCostResponseBreakdownApplication`

      - `const SmallMoleculeDesignEstimateCostResponseBreakdownApplicationStructureAndBinding SmallMoleculeDesignEstimateCostResponseBreakdownApplication = "structure_and_binding"`

      - `const SmallMoleculeDesignEstimateCostResponseBreakdownApplicationSmallMoleculeDesign SmallMoleculeDesignEstimateCostResponseBreakdownApplication = "small_molecule_design"`

      - `const SmallMoleculeDesignEstimateCostResponseBreakdownApplicationSmallMoleculeLibraryScreen SmallMoleculeDesignEstimateCostResponseBreakdownApplication = "small_molecule_library_screen"`

      - `const SmallMoleculeDesignEstimateCostResponseBreakdownApplicationProteinDesign SmallMoleculeDesignEstimateCostResponseBreakdownApplication = "protein_design"`

      - `const SmallMoleculeDesignEstimateCostResponseBreakdownApplicationProteinLibraryScreen SmallMoleculeDesignEstimateCostResponseBreakdownApplication = "protein_library_screen"`

      - `const SmallMoleculeDesignEstimateCostResponseBreakdownApplicationAdme SmallMoleculeDesignEstimateCostResponseBreakdownApplication = "adme"`

    - `CostPerUnitUsd string`

      Estimated cost per displayed unit as a decimal string, rounded up to 4 decimal places. This may include token-size multipliers or generation overhead; estimated_cost_usd is the authoritative total.

    - `NumUnits int64`

      Number of units shown for the estimate. For structure-and-binding, this is the requested number of samples. For protein and small-molecule design/screen endpoints, this is the requested number of proteins or molecules.

  - `Disclaimer string`

  - `EstimatedCostUsd string`

    Estimated total cost as a decimal string

### Example

```go
package main

import (
  "context"
  "fmt"

  "github.com/boltz-bio/boltz-api-go"
  "github.com/boltz-bio/boltz-api-go/option"
)

func main() {
  client := boltzapi.NewClient(
    option.WithAPIKey("My API Key"),
  )
  response, err := client.SmallMolecule.Design.EstimateCost(context.TODO(), boltzapi.SmallMoleculeDesignEstimateCostParams{
    NumMolecules: 10,
    Target: boltzapi.SmallMoleculeDesignEstimateCostParamsTarget{
      Entities: []boltzapi.SmallMoleculeDesignEstimateCostParamsTargetEntity{boltzapi.SmallMoleculeDesignEstimateCostParamsTargetEntity{
        ChainIDs: []string{"string"},
        Value: "value",
      }},
    },
  })
  if err != nil {
    panic(err.Error())
  }
  fmt.Printf("%+v\n", response.Breakdown)
}
```