# NCBI dbSNP Variant Lookup by rs Number

> NCBI dbSNP Variant Lookup by rs Number is a paid API for AI agents from api.healthtravel-api.workers.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-29).

Retrieves a dbSNP short variant record by rs number, including variant type, genomic placement, reference/alternate alleles, and population allele frequencies from studies like 1000 Genomes.

## Facts

- Endpoint: GET https://api.healthtravel-api.workers.dev/api/health/dbSNP-polymorphisms?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/ncbi-dbsnp-variant-lookup-by-rs-number-35aec478
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_nSgyBhegEa26SN3ON07lx

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-dbsnp-variant-lookup-by-rs-number-35aec478
```

Example prompt: Can you look up the dbSNP record for rs429358 and tell me its variant type, chromosomal position, reference and alternate alleles, and allele frequencies from the 1000 Genomes study?

## When to prefer this

Use this endpoint when you need structured, machine-readable dbSNP data for a specific rs number — particularly genomic placement coordinates and population allele frequencies — without scraping the NCBI website directly. It is ideal for bioinformatics pipelines, genetic risk assessment tools, or research agents needing to enrich variant data with frequency context. Prefer this over raw NCBI API calls when you need a clean JSON response with normalized frequency rows and do not need full annotation depth beyond 10 frequency entries.

## Known failure modes

- Invalid or non-existent rsid returns an error or empty result
- rsid without population frequency data returns an empty frequencies array
- Network timeout if NCBI dbSNP upstream is slow
- Malformed rsid (missing 'rs' prefix or non-numeric) may return a validation error
- Only up to 10 frequency rows returned per call; large variant records may be truncated

## How this service works

NCBI dbSNP short variant record by rs number: variant type, placement (sequence and position), reference and alternate sequence, and study allele frequencies (e.g. 1000 Genomes allele counts). Up to 10 frequency rows per call.

## Output

Returns a JSON object containing the rsid, source URL, timestamp, placement details (chromosome position, sequence ID, reference allele, alternate allele), variant type (e.g. 'snv'), and up to 10 allele frequency rows from population studies (study name, allele sequence, total count, allele count).

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "rsid"
     ],
     "properties": {
      "rsid": {
       "type": "string",
       "description": "dbSNP rs number, e.g. rs429358"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "rsid": "rs429358",
  "source": "https://www.ncbi.nlm.nih.gov/snp/rs429358",
  "checkedAt": "2026-10-23T09:36:30.141Z",
  "placement": {
   "position": 44908683,
   "sequenceId": "NC_000019.10",
   "alternateAllele": "T",
   "referenceAllele": "T"
  },
  "frequencies": [
   {
    "study": "1000Genomes",
    "sequence": "T",
    "totalCount": 5008,
    "alleleCount": 4254
   },
   {
    "study": "1000Genomes_30X",
    "sequence": "T",
    "totalCount": 6404,
    "alleleCount": 5436
   }
  ],
  "variantType": "snv"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/ncbi-dbsnp-variant-lookup-by-rs-number-35aec478/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.healthtravel-api.workers.dev](https://www.zero.xyz/host/api.healthtravel-api.workers.dev/llms.txt)