Measurement Log
What we recorded calling every API
This page is the raw output of our own testing, not a summary of anyone's marketing material. We send real HTTP requests to public API endpoints and record what comes back — status, latency, transport security, CORS headers and rate-limit headers. Nothing here is estimated, inferred or copied from a provider's documentation.
LAST RUN 2026-08-10
Latest run
271
endpoints called
244 ms
median response time
891 ms
90th percentile
257
responses captured
220
browser-callable (CORS)
235
negotiated TLS 1.3
41
published rate-limit headers
214
confirmed discontinued
1,212 of 1,426 catalogued APIs currently respond. 271 of those expose an endpoint we can call without credentials, so only those carry measured scores; the rest are scored from metadata and labelled as such on their pages.
Response time distribution
Median of three consecutive requests per endpoint, measured from a single vantage point. Your latency will differ by region — treat these as relative, not absolute.
Fastest endpoints we measured
Ranked by median response time across three requests.
| API | Category | Response | CORS | TLS |
|---|---|---|---|---|
| VALR | Cryptocurrency | 27 ms | no | TLSv1.3 |
| xkcd | Games & Comics | 29 ms | no | TLSv1.2 |
| Nominatim | Geocoding | 29 ms | yes | TLSv1.3 |
| FreeToGame | Games & Comics | 30 ms | yes | TLSv1.3 |
| Drupal.org | Open Source Projects | 30 ms | yes | TLSv1.2 |
| Final Space | Video | 30 ms | yes | TLSv1.3 |
| AviationWeather | Weather | 30 ms | no | TLSv1.3 |
| GrünstromIndex | Environment | 31 ms | yes | TLSv1.3 |
| Chess.com | Games & Comics | 31 ms | yes | TLSv1.3 |
| Dev.to | Personality | 31 ms | yes | TLSv1.2 |
| Currency-api | Currency Exchange | 32 ms | yes | TLSv1.3 |
| An API of Ice And Fire | Video | 32 ms | yes | TLSv1.3 |
| Postali | Geocoding | 33 ms | yes | TLSv1.3 |
| Coronavirus in the UK | Health | 33 ms | yes | TLSv1.3 |
| Imgflip | Entertainment | 34 ms | yes | TLSv1.3 |
Transport security observed
TLS version actually negotiated during our requests.
Run history
Each weekly run calls every live endpoint again. Endpoints that stop answering drop out of the measured tier until they work again.
| Run | Endpoints tested | Answered with data |
|---|---|---|
| 2026-08-10 | 1213 | 271 |
| 2026-07-31 | 1213 | 252 |
How this is produced
- For each catalogued API we look for a callable endpoint — in its own code samples, in its documentation page, or at conventional paths on its own domain. Placeholder URLs and credentials are excluded.
- We send a GET request with a normal browser user agent and follow redirects. A response only counts as measured if it returns 2xx and valid JSON that is not an error envelope, a service banner, or an HTML page.
- We repeat the request three times and record the median and fastest round trip, plus the TLS protocol, certificate issuer, CORS header, rate-limit headers, content type and payload size.
- The response body is stored, truncated for readability, and shown on the API's page as a captured response.
- Endpoints that stop responding are re-checked; an API is only marked discontinued after two independent DNS resolvers confirm its host no longer exists.
Measurements come from a single network location and reflect one moment in time. They are a reproducible signal, not a service-level guarantee. See how API Score works for how these signals turn into a score.