# NCBI Taxonomy Lookup by Taxon

> NCBI Taxonomy Lookup by Taxon is a paid API for AI agents from saylorinnovations.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-27).

Returns taxonomic rank, common name, named lineage, genome assembly count, gene counts, and child taxa for a given NCBI taxon ID or scientific name.

## Facts

- Endpoint: GET https://saylorinnovations.com/api/species/taxonomy/:taxon?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-27
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ncbi-taxonomy-lookup-by-taxon-a11891bb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ro7cy4nsPCCTd5fecGKz3

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability ncbi-taxonomy-lookup-by-taxon-a11891bb
```

Example prompt: Can you look up the NCBI taxonomy for Homo sapiens — I need the rank, lineage, common name, genome assembly count, gene counts, and any child taxa?

## When to prefer this

Use this endpoint when you need authoritative NCBI-sourced taxonomic classification data including lineage, genome assembly counts, and gene counts for a specific organism identified by scientific name or NCBI taxon ID. Prefer this over general web searches when structured, machine-readable taxonomy data is required for bioinformatics pipelines, database enrichment, or research workflows.

## Known failure modes

- Unknown or misspelled taxon name returns 404 or empty result
- Ambiguous scientific name with multiple matches may return unexpected taxon
- Taxon IDs that are deprecated or merged in NCBI may return no result
- Network timeout or upstream NCBI service unavailability

## How this service works

NCBI Taxonomy lookup by tax id or scientific name - rank, common name, named lineage, genome assembly count, gene counts and child taxa

## Output

Returns the taxonomic rank (e.g. species, genus, family), common name, full named lineage array, number of genome assemblies, gene counts, and list of child taxa for the queried organism — sourced from NCBI Taxonomy.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "pathParams"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object",
     "required": [
      "taxon"
     ],
     "properties": {
      "taxon": {
       "type": "string",
       "description": "NCBI tax id or scientific name in the path, e.g. 9606, Canis%20lupus"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "json"
    },
    "example": {
     "type": "object",
     "required": [
      "tax_id",
      "scientific_name"
     ],
     "properties": {
      "url": {
       "type": "string",
       "description": "Canonical URL"
      },
      "rank": {
       "type": [
        "string",
        "null"
       ],
       "description": "Rank, 1 is highest"
      },
      "genes": {
       "type": [
        "number",
        "null"
       ],
       "description": "Number of genes annotated for this taxon in NCBI Gene"
      },
      "source": {
       "type": "string",
       "description": "Data source the values come from"
      },
      "tax_id": {
       "type": "number",
       "description": "Tax id identifier"
      },
      "lineage": {
       "type": "array",
       "description": "Ancestors of the taxon from root to parent, each with NCBI tax id, name and rank"
      },
      "blast_name": {
       "type": [
        "string",
        "null"
       ],
       "description": "Blast name"
      },
      "common_name": {
       "type": [
        "string",
        "null"
       ],
       "description": "Common name"
      },
      "genomic_moltype": {
       "type": [
        "string",
        "null"
       ],
       "description": "Genomic moltype"
      },
      "scientific_name": {
       "type": "string",
       "description": "Scientific name"
      },
      "child_taxa_count": {
       "type": "number",
       "description": "Number of child taxa"
      },
      "genome_assemblies": {
       "type": [
        "number",
        "null"
       ],
       "description": "Genome assemblies"
      },
      "protein_coding_genes": {
       "type":
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ncbi-taxonomy-lookup-by-taxon-a11891bb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from saylorinnovations.com](https://www.zero.xyz/host/saylorinnovations.com/llms.txt)