oha

Send 100 requests to URL

$ oha -n [100] [https://example.com]

$ oha -z [30s] [https://example.com]

$ oha -c [50] -n [1000] [https://example.com]

$ oha -m POST -d '[{"key":"value"}]' -T application/json [https://example.com/api]

$ oha -H "Authorization: Bearer [token]" [https://example.com]

$ oha -q [100] -z [30s] [https://example.com]

$ oha --insecure [https://example.com]

$ oha -n [100] --json [https://example.com]

oha [options] url

oha is an HTTP load generator written in Rust, inspired by hey and rakyll/hey. It provides real-time TUI visualization during load tests and detailed latency statistics.
By default, oha displays a terminal interface showing request progress, latency distribution, and error rates. Use --no-tui for scripted execution or --json for machine-readable output.
The tool measures response time distribution including percentiles (p50, p90, p99), throughput, and error rates. With --latency-correction, it applies coordinated omission correction for accurate latency under load.
Rate limiting with -q enables controlled load testing without overwhelming targets. Combined with -z for duration-based tests, this enables realistic traffic simulation.
oha supports HTTP/1.1 and HTTP/2, custom headers for authentication, and various request body formats for API testing.

-n num

Number of requests to send. Default: 200.

Number of concurrent connections. Default: 50.

Duration of test (e.g., 10s, 1m).

Rate limit in queries per second.

HTTP method: GET, POST, PUT, DELETE, etc.

Request body data.

Read request body from file.

Content-Type header value.

Custom header (repeatable).

Accept header value.

Request timeout in seconds.

Enable coordinated omission correction.

Disable real-time terminal UI.

Output results in JSON format.

Skip TLS certificate verification.

Use HTTP/2.

Override Host header.

Maximum redirects to follow.

High concurrency settings may exhaust file descriptors or network resources. Use --insecure cautiously. Rate limiting accuracy depends on system capabilities. Results should be interpreted considering network conditions.

oha was created by Haruki Shimada (hatoo) and first released around 2020. The name means "good morning" in Japanese. Written in Rust using tokio for async I/O, it provides modern load testing with real-time visualization. The project gained popularity as a fast, user-friendly alternative to older tools like ab and wrk.

hey(1), wrk(1), ab(1), curl(1), siege(1)