hatoo/oha · error · anyhow::Error

Your Oha instance has not been built with HTTP/3 support…

Error message

Your Oha instance has not been built with HTTP/3 support. Try recompiling with the feature enabled.

What it means

`--http-version 3` (or 3.0) maps to HTTP/3, which is gated behind the optional `http3` cargo feature. When the binary was compiled without that feature, the 3.x arm bails with this message instead of producing an HTTP/3 version. The binary runs fine otherwise; only HTTP/3 is unavailable.

Solutions

  1. Rebuild oha with the http3 feature enabled: `cargo install oha --features http3` (or build from source with that feature).
  2. Use a build/distribution known to include HTTP/3 support.
  3. Fall back to HTTP/2 (`--http-version 2`) if HTTP/3 is not essential.

Example fix

// before
cargo install oha
oha --http-version 3 https://example.com
// after
cargo install oha --features http3
oha --http-version 3 https://example.com
Defensive patterns

Strategy: fallback

Validate before calling

fn http3_supported(build_features: &[&str]) -> bool {
    build_features.contains(&"http3")
}

Try / catch

match run(opts).await {
    Err(e) if e.to_string().contains("not been built with HTTP/3 support") => {
        eprintln!("Falling back to HTTP/2");
        opts.http_version = Some("2".into());
        run(opts).await
    }
    Err(e) => return Err(e),
    Ok(v) => v,
}

Prevention

When it happens

Trigger: Running an oha binary built without `--features http3` and passing `--http-version 3` or `--http-version 3.0`.

Common situations: Installing oha from a package manager or prebuilt binary that omits the http3 feature; CI environments using a default build.

Related errors

AI-assisted analysis of hatoo/oha@4efba2d113 (2026-09-09). Data as JSON: /api/errors/e4c94e76c3f5db7c. Report an issue: GitHub.

Appendix: source

Thrown at src/main.rs:383

        } else {
            anyhow::bail!("AWS credentials (--auth) required when using --aws-sigv4");
        }
    } else {
        None
    };

    let parse_http_version = |is_http2: bool, version: Option<&str>| match (is_http2, version) {
        (true, Some(_)) => anyhow::bail!("--http2 and --http-version are exclusive"),
        (true, None) => Ok(http::Version::HTTP_2),
        (false, Some(http_version)) => match http_version.trim() {
            "0.9" => Ok(http::Version::HTTP_09),
            "1.0" => Ok(http::Version::HTTP_10),
            "1.1" => Ok(http::Version::HTTP_11),
            "2.0" | "2" => Ok(http::Version::HTTP_2),
            #[cfg(feature = "http3")]
            "3.0" | "3" => Ok(http::Version::HTTP_3),
            #[cfg(not(feature = "http3"))]
            "3.0" | "3" => anyhow::bail!(
                "Your Oha instance has not been built with HTTP/3 support. Try recompiling with the feature enabled."
            ),
            _ => anyhow::bail!("Unknown HTTP version. Valid versions are 0.9, 1.0, 1.1, 2, 3"),
        },
        (false, None) => Ok(http::Version::HTTP_11),
    };

    let http_version: http::Version = parse_http_version(opts.http2, opts.http_version.as_deref())?;
    let proxy_http_version: http::Version =
        parse_http_version(opts.proxy_http2, opts.proxy_http_version.as_deref())?;

    let url_generator = if opts.rand_regex_url {
        // Almost URL has dot in domain, so disable dot in regex for convenience.
        let dot_disabled: String = url
            .chars()
            .map(|c| {
                if c == '.' {
                    regex_syntax::escape(".")

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