About LatencyLens

Everything About This API Performance Tool

LatencyLens is a lightweight web tool to test REST API performance by sending repeated requests and analyzing speed, reliability, and stability under load.

Back to Home

What LatencyLens Does

Runs repeated API requests (1 to 100) against a target endpoint.
Measures latency for every request in milliseconds.
Calculates percentile and spread metrics for deeper performance visibility.
Shows success rate, request-level status, and performance insights.
Supports GET, POST, PUT, DELETE, and PATCH methods.
Exports test reports in JSON and CSV formats for sharing and archives.

How Testing Works

Enter an endpoint URL.
Select HTTP method.
Set request count.
Optionally add JSON request body and custom headers.
Run the test and review metrics, insights, and request details.

Tip: For method-specific testing examples, use endpoints from httpbin.org.

Metrics Explained

Average Latency

Mean response time across all requests.

P50 Latency

Median response time. Half of requests are faster than this value.

P95 Latency

95th percentile latency, helpful for understanding near-worst normal behavior.

P99 Latency

99th percentile latency, useful for identifying tail-latency spikes.

Fastest / Slowest

Best and worst observed response times in the current test run.

Response Time Range

Difference between slowest and fastest latency values.

Success Rate

Percentage of successful responses (HTTP 2xx and 3xx).

Stability Score

Standard deviation of latencies. Lower means more consistent response time.

Current Scope and Limits

Request count per test: 1 to 100
Default timeout: 10 seconds per request
Supported protocols: HTTP and HTTPS only
No database persistence in current version

Why LatencyLens

LatencyLens focuses on practical API performance checks with minimal setup. It is ideal for developers and teams who need fast, repeatable measurements for endpoint behavior without heavy tooling.