ITIS API

Free to Use
46 D
Measured Score 0 50 100 Speed 5/30 Consistency 17/20 Security 20/20 Browser access 0/15 Transparency 4/15 TESTED 2026-08-10

Overview

ITIS (Integrated Taxonomic Information System) is a free API providing authoritative taxonomic data on plants, animals, fungi, and microbes. You can look up the official scientific classification of any organism by name, Taxonomic Serial Number (TSN), or common name. It is maintained by US government agencies and is highly reliable for biodiversity and biology projects.

Beginner Tip

Search by common name first using the searchByCommonName endpoint to find the TSN, then use that TSN to retrieve full hierarchical classification. All responses are available in JSON by using the /jsonservice/ path in the URL.

Measurement Record

What actually happened when we called this API from our own infrastructure. Every value below was recorded by the request, not copied from the provider's documentation.

Request
GET https://www.itis.gov/ITISWebService/jsonservice/searchByCommonName?srchKey=bald+eagle
Result
HTTP 200 · text/json · 209 bytes
Response time
579 ms (median of 3) · fastest 551 ms
Transport
TLSv1.3 · TLS_AES_256_GCM_SHA384 · certificate issued by Internet2
Browser CORS
No Access-Control-Allow-Origin header — call it from a server, not the browser
Recorded
2026-08-10

Fields Returned

Top-level fields present in the response we captured, with the type and value we actually received.

Field Type Value received
class string gov.usgs.itis.itis_service.data.SvcCommonName…
commonNames array [1 item]
tsn null null

Captured Response

Captured from a real request to https://www.itis.gov/ITISWebService/jsonservice/searchByCommonName?srchKey=bald+eagle on 2026-08-10. Long arrays and nested objects are truncated to keep the shape readable.

JSON Response · Captured
{
  "class": "gov.usgs.itis.itis_service.data.SvcCommonNameList",
  "commonNames": [
    {
      "class": "gov.usgs.itis.itis_service.data.SvcCommonName",
      "commonName": "Bald Eagle",
      "language": "English",
      "tsn": "175420"
    }
  ],
  "tsn": null
}

Field Reference

tsn Taxonomic Serial Number — the unique ITIS identifier for a taxon.
commonNames List of common name objects with name and language.

Implementation Example

Calls a real endpoint of this API. Replace any placeholder credentials with your own key.

Request
const url = "https://www.itis.gov/";
const response = await fetch(url);
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data);

What Can You Build?

Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.

How This API Fails

We deliberately sent this API a broken request and recorded exactly what came back on 2026-08-10. Knowing the shape of an error before you hit it makes error handling much easier to write.

HTTP 404 Requesting a path that does not exist text/html

Returned an HTML error page rather than JSON — worth knowing if your client assumes every response can be parsed as JSON.

Common Errors & Troubleshooting

Generated guidance based on this API's documentation, not observed by us. Treat it as a starting point and check against the provider's own error reference.

null in commonNameList The common name was not found in the ITIS database.
Try the scientific name search endpoint or check for spelling variations of the common name.
XML response instead of JSON Using the wrong service endpoint URL (SOAP vs REST/JSON).
Use the /jsonservice/ path in the URL to get JSON responses instead of XML.
Slow response times The ITIS web service can be slow on large hierarchical queries.
Cache results locally since taxonomic data changes infrequently and avoid repeated identical requests.

Measured Score Breakdown

Live HTTP request to the API endpoint

Speed 5/30
Consistency 17/20
Security 20/20
Browser access 0/15
Transparency 4/15
Endpoint Response Time 579ms

Fully tested on Aug 10, 2026

Technical Specifications

Auth No Auth
HTTPS REQUIRED
CORS UNKNOWN
Category Science & Math
Difficulty Beginner
Endpoint last called: 2026-08-10

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