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API Reference

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This documentation contains the API reference for the MSA Search NIM.

OpenAPI Specification

You can download or view the OpenAPI specification when the NIM is running:

curl http://localhost:8000/openapi.json

You can also navigate to the interactive API documentation at http://localhost:8000/docs in your browser.

Endpoint path: /biology/colabfold/msa-search/predict

Request type: POST

Input Parameters

  • sequence (string, required): A sequence to search against the MSA databases. Must be a valid protein sequence composed of the 20 standard amino acids (ARNDCQEGHILKMFPSTWYV). Length: 1-4096 characters.

    Example:

    "SGSMKTAISLPDETFDRVSRRASELGMSRSEFFTKAAQR"

  • databases (list[string], optional): Database names to search against. All databases are searched by default. Database names are case-insensitive; the response preserves the case you specify. Default: ["all"].

    Important: For ColabFold search type, the first database in the list is used for profile generation. When using ["all"], uniref30 is automatically placed first.

    Examples: ["all"], ["uniref30_2302"], ["uniref30_2302", "pdb70_220313"]

  • search_type (string, optional): Which type of MSA Search to run for alignment production. Default: "colabfold".

    Options:

    • "colabfold": Cascaded search with higher sensitivity. The first database is used for profile generation.
    • "alphafold2": Single-pass iterative search

    Examples: "colabfold", "alphafold2"

  • e_value (float, optional): The e-value threshold for filtering hits when building the Multiple Sequence Alignment. Sequences with an e-value greater than this are not included in the MSA. Range: 0.0-1.0. Default: 0.0001.

  • iterations (int, optional): The number of MSA iterations to perform, where more iterations find more distant homologs. Default: 1. Note: For cascaded search (search_type="colabfold"), the number of iterations is fixed to 3 and this parameter is ignored.

  • max_msa_sequences (int, optional): The maximum sequences taken from the MSA for model prediction. Default: 500. Note: When GPU Server is enabled (default in version 2.0.0), this parameter must be set globally using the NIM_GLOBAL_MAX_MSA_DEPTH environment variable at container startup.

  • output_alignment_formats (list[string], optional): The output format of the MSA. Supported formats: "a3m", "fasta". Default: ["a3m"].

    Examples: ["a3m"], ["a3m", "fasta"]

Endpoint path: /biology/colabfold/msa-search/paired/predict

Request type: POST

Paired MSA search finds homologous sequences for each chain of a protein complex and pairs them by species, preserving co-evolutionary signals across chains. This is essential for accurate structure prediction of protein complexes.

Input Parameters

  • sequences (list[string] or dict[string, string], required): Protein sequences, one per chain. Must contain at least 2 sequences. Each sequence must be composed of the 20 standard amino acids (ARNDCQEGHILKMFPSTWYV). Can be provided as a list (chain IDs assigned automatically as identifiers such as “A” and “B”) or as a dictionary keyed by chain ID.

    Examples:

    ["VLSPADKTNVKAAWGKVGAHAGEYGAEALERMFLSFPTTKTYFPHFDLSH", "MHLTPEEKSAVTALWGKVNVDEVGGEALGRLLVVYPYTQRFFESFGDLST"]
    {"A": "VLSPADKTNVKAAWGKVGAHAGEYGAEALERMFLSFPTTKTYFPHFDLSH", "B": "MHLTPEEKSAVTALWGKVNVDEVGGEALGRLLVVYPYTQRFFESFGDLST"}

  • databases (list[string], optional): Databases to search against. Only databases with taxonomy information can be used for paired search. Database names are case-insensitive; the response preserves the case you specify. Default: ["all"].

    Examples: ["all"], ["uniref30_2302"]

  • e_value (float, optional): The e-value threshold for filtering hits when building the Multiple Sequence Alignment. Sequences with an e-value greater than this are not included in the MSA. Range: 0.0-1.0. Default: 0.0001.

  • max_msa_sequences (int, optional): Maximum sequences taken from the MSA per chain (only applies when unpack=True; when unpack=False, row count may exceed NIM_GLOBAL_MAX_MSA_DEPTH due to MMseqs2 internal pipeline behavior where prefilter limits are per-step, not strict global caps). Default: 500. Note: When GPU Server is enabled (default since version 2.0.0), this parameter must be set globally using the NIM_GLOBAL_MAX_MSA_DEPTH environment variable at container startup.

  • pairing_strategy (string, optional): Pairing strategy for cross-chain sequence matching. Default: "greedy".

    Options:

    • "greedy": Maximizes rows by including species with partial chain coverage, pairing all chains that have hits and leaving gaps in others.
    • "complete": Only includes species where all chains have hits, producing fewer rows but with full coverage.

For 2-chain searches, both strategies produce identical results. Differences only arise for 3+ chains.

  • unpack (boolean, optional): Controls output format. Default: True.

    • True: Returns N alignments (one per chain) keyed by chain ID (for example, “A”, “B”), each strictly limited to max_msa_sequences rows.
    • False: Returns raw MMseqs2 output as a single “all_chains” alignment with chains concatenated using null-byte separators. Row count may exceed NIM_GLOBAL_MAX_MSA_DEPTH due to MMseqs2 internal pipeline behavior (prefilter limits are per-step, not strict global caps).

Outputs

  • alignments_by_chain (Dictionary[string → Dictionary[string → Dictionary[string → AlignmentFileRecord]]]): Paired MSA alignments organized by chain ID. When unpack=True, structure is {chain_id: {database_name: {format: AlignmentFileRecord}}}. When unpack=False, contains a single “all_chains” key with the concatenated paired alignment.

    Example response (with unpack=True):

    {
      "alignments_by_chain": {
        "A": {
          "uniref30_2302": {
            "a3m": {
              "alignment": ">A|-|A\nVLSPADKTNVKAAWGKV...\n>UniRef100_UPI00148F070C...\nVLSPAD...",
              "format": "a3m"
            }
          }
        },
        "B": {
          "uniref30_2302": {
            "a3m": {
              "alignment": ">B|-|B\nMHLTPEEKSAVTALWGKV...\n>UniRef100_UPI0008DEA318...\nMHLTPE...",
              "format": "a3m"
            }
          }
        }
      },
      "metrics": {}
    }

    To access the A3M-formatted alignment for chain A from the uniref30_2302 database:

    alignments_by_chain["A"]["uniref30_2302"]["a3m"]["alignment"]

  • metrics (dictionary, optional): Contains information about the response useful for debugging and measuring performance. May be empty or null.

The output format for paired MSA search is always A3M.

Endpoint path: /biology/colabfold/msa-search/structure-templates/predict

Request type: POST

Structural template search finds homologous protein structures by searching PDB-based databases and retrieves the corresponding mmCIF structure files. This endpoint combines MSA generation with template discovery in a single request, providing all inputs needed for template-based structure prediction.

Input Parameters

  • sequence (string, required): A protein sequence to search against the databases. Must be composed of the 20 standard amino acids (ARNDCQEGHILKMFPSTWYV). Length: 1-4096 characters.

    Example:

    "SGSMKTAISLPDETFDRVSRRASELGMSRSEFFTKAAQR"

  • structural_template_databases (list[string], optional): List of databases to search for structural templates. Database names are case-insensitive; the response preserves the case you specify. Default: value of NIM_MSA_API_DEFAULT_STRUCTURAL_TEMPLATE_DBS environment variable (typically ["pdb70_220313"]).

    Examples: ["pdb70_220313"], ["pdb70_220313", "pdb100_230517"]

  • msa_databases (list[string], optional): Database names to search for MSA generation. The first database is used for profile generation, which determines template search results. Database names are case-insensitive; the response preserves the case you specify. Default: ["all"].

    Examples: ["all"], ["uniref30_2302"]

  • e_value (float, optional): The e-value threshold for filtering hits. Range: 0.0-1.0. Default: 0.0001.

  • max_structures (int, optional): Maximum number of PDB structures to return from template search. Default: 20.

  • max_msa_sequences (int, optional): Maximum sequences used for profile generation and MSA output. Default: 500.

Outputs

The response includes the same fields as the standard MSA search endpoint, plus template-specific outputs:

  • alignments: MSA alignments organized by database and format (same as standard MSA search)

  • search_hits (Dictionary[string → Dictionary[string → SearchHitRecord]]): Structural template hits organized by database. Each entry contains template hits in M8 (BLAST tabular) format.

    Each SearchHitRecord contains:

    • hits (string): Template hits with columns: query, target, fident, alnlen, mismatch, gapopen, qstart, qend, tstart, tend, evalue, bits, cigar. The output format can be customized via the NIM_MMSEQS_CONVERTALIS_FORMAT environment variable.
    • format (string): Always "m8".

  • structures (Dictionary[string → StructuralTemplate]): Retrieved PDB structures for template hits, organized by PDB ID.

    Each StructuralTemplate contains:

    • structure (string): The mmCIF file content
    • format (string): Always "mmcif"

  • metrics (dictionary, optional): Performance and debugging information

Example response:

{
  "alignments": {
    "uniref30_2302": {
      "a3m": {
        "alignment": ">query\nMVPSAGQLALF...",
        "format": "a3m"
      }
    },
    "colabfold": {
      "a3m": {
        "alignment": ">query\nMVPSAGQLALF...",
        "format": "a3m"
      }
    }
  },
  "search_hits": {
    "pdb70_220313": {
      "m8": {
        "hits": "query\t1abc_A\t85.0\t150\t...",
        "format": "m8"
      }
    }
  },
  "structures": {
    "1abc": {
      "structure": "data_1ABC\n_entry.id 1ABC\n...",
      "format": "mmcif"
    }
  },
  "metrics": {}
}

Template search uses the ColabFold cascaded search approach internally. The profile generated from the first MSA database (e.g., uniref30_2302) is used to find structural templates.

Get Database Configuration

Endpoint path: /biology/colabfold/msa-search/config/msa-database-configs

Request type: GET

Deprecated: This endpoint is deprecated in favor of /v1/metadata and will be removed in MSA 3.0. Use the /v1/metadata endpoint to retrieve information about available databases and model profiles.

Input Parameters

None.

Outputs

  • configs (dictionary): A nested dictionary containing information about all configured MSA databases. The configuration can be converted to YAML format to view the original database configuration.

Get MMSeqs2 Version

Endpoint path: /biology/colabfold/msa-search/mmseqs2/version

Request type: GET

Input Parameters

None.

Outputs

Returns version information for the MMSeqs2 installation used by the NIM.

Use this endpoint to get the exact MMSeqs2 version when you need to create custom database indices. Custom indices must be created with the same MMSeqs2 version as the one running in the NIM to ensure compatibility.

Health Endpoints

Readiness Check

Endpoint path: /v1/health/ready

Request type: GET

Description: Checks if the service is ready to handle requests.

Outputs

  • Status code 200: Service is ready
  • Status code 503: Service is not ready

Response includes a JSON object with:

  • message (string): Status message
  • object (string): Always “health.response”
  • status (string, optional): Status string for backwards compatibility

Liveness Check

Endpoint path: /v1/health/live

Request type: GET

Description: Checks if the service is live (running).

Outputs

  • Status code 200: Service is live
  • Status code 503: Service is not live

Response format is the same as the readiness check.

NIM Metadata Endpoints

Version

Endpoint path: /v1/version

Request type: GET

Description: Returns version information for the NIM.

Outputs

  • release (string): The product release version of the NIM
  • api (string): The server API version running inside the NIM

License

Endpoint path: /v1/license

Request type: GET

Description: Returns license information for the NIM.

Outputs

  • name (string): The name of the license
  • path (string): The filepath within the container containing the license content
  • sha (string): SHA1 hash of the license contents
  • size (integer): Number of characters in the license content
  • url (string): URL where the license is hosted externally
  • type (string): Always “file”
  • content (string): The full license text

Metadata

Endpoint path: /v1/metadata

Request type: GET

Description: Returns comprehensive metadata about the NIM deployment.

Outputs

  • assetInfo (list[string]): Required container assets excluding model artifacts
  • licenseInfo (LicenseEndpointModel): License information
  • modelInfo (list[ModelInfo]): Information about models being served
  • repository_override (string): Alternate location for retrieving artifacts
  • version (string): NIM service version
  • selectedModelProfileId (string): ID of the currently selected model profile

Manifest

Endpoint path: /v1/manifest

Request type: GET

Description: Returns the manifest file describing required model artifacts.

Outputs

  • manifest_file (string): Content of the manifest file
  • repository_override (string): Alternate location for retrieving artifacts

Metrics

Endpoint path: /v1/metrics

Request type: GET

Description: Exposes Prometheus metrics for monitoring.

Outputs

Returns metrics in Prometheus format.