What does the reported time include?

Elapsed milliseconds cover DNS, TLS handshake, request transfer, server processing, and response download as experienced by your browser—not server-only processing time.

Can I test POST endpoints?

Yes where CORS allows. Include method, headers, and JSON body like the API Request Builder. Preflight OPTIONS may add overhead not present in server-side benchmarks.

Why do times vary run to run?

Cold DNS, TLS session resumption, cache HIT/MISS headers, and Wi-Fi jitter all swing results. Run several samples and compare medians, not single shots.

Briefly Digest

API Response Time Tester

Fire multiple requests to the same URL and compare response times reported by the browser performance clock.

Number 1 Number 2 Number 3 Option

Input text

Secondary input

Image/file input

Result

Ready.

Latency snapshots from the user's network path

Server APM charts exclude last-mile ISP latency. Testing from a browser reproduces what mobile users feel, especially on TLS-heavy APIs with small payloads where handshake dominates.

Interpreting spikes

A jump from 80 ms to 400 ms on the same URL may indicate cache bypass, regional routing changes, or throttling. Capture response headers like cf-cache-status or x-cache on each run.

Not a load test

Sequential browser requests won't saturate your backend. Use proper load generators for capacity planning; this tool answers "is it slow for me right now?"

FAQ

What does the reported time include?: Elapsed milliseconds cover DNS, TLS handshake, request transfer, server processing, and response download as experienced by your browser—not server-only processing time.
Can I test POST endpoints?: Yes where CORS allows. Include method, headers, and JSON body like the API Request Builder. Preflight OPTIONS may add overhead not present in server-side benchmarks.
Why do times vary run to run?: Cold DNS, TLS session resumption, cache HIT/MISS headers, and Wi-Fi jitter all swing results. Run several samples and compare medians, not single shots.

Related tools

Continue your workflow with calculators in the same topic.

Compare tools side by side →

Related guides

Blog articles that add context around this calculator.

FIRE Calculator: Plan Your Financial Independence & Early Retirement 2026-07-20
Secure Password Generator: Create Strong Passwords Online 2026-07-19
Interest Only Loan Calculator: Plan Your Payments with Ease 2026-07-13

All articles →