kload

Lightweight CLI load-testing-tool for HTTPS-Endpoints written in Go.

About

kload is a lightweight HTTP load testing tool built in Go. It sends a configurable number of concurrent requests against an endpoint and reports back latency percentiles, throughput, and status code breakdowns and therefore everything you need to understand how a service behaves under pressure.

It's built with zero external dependencies, relying entirely on the Go standard library. That keeps the binary small, the build fast, and the codebase easy to audit.

The concurrency model is a straightforward worker pool: a fixed number of goroutines pull jobs from a channel and feed results back through another, which makes the load behaviour predictable and the code easy to reason about.

Why use kload?

• Zero dependencies
• Complete metrics (latency in min, max, mean, p50, p90, ...)
• Built for both humans and pipelines
  • Readable table output for interactive use and JSON or CSV for CI integration and further analysis
• Realistic load shaping
  • Cap requests per second, run for a fixed duration or a fixed request count, and use warmup phases to exclude cold-start noise from your results

---

Usage

By invoking the command kload the following flags can be used:

Flag	Parameter type	Required	Description	Usage example
-u, --url	URL	Yes	Target URL to load test	-u https://example.com
-m, --method	Text	No	HTTP method (GET, POST, PUT, PATCH, DELETE)	-m GET
-H, --header	Text	No	Request headers, repeatable	-H "Content-Type: application/json"
-b, --body	Text	No	Request body as raw string (used with POST/PUT)	-b '{"user":"test"}'
--body-file	Path	No	Read request body from file instead of inline string	--body-file body.json
-n, --requests	Integer	No	Total number of requests to send	-n 100
-c, --concurrency	Integer	No	Total number of concurrent workers sending requests	-c 10
-d, --duration	Duration	No	Run for a fixed duration instead of a fixed request count	-d 30ms
-rps	Integer	No	Cap requests per second (useful for rate-limit testing, 0 = unlimited)	-rps 30
--warmup	Integer	No	Number of warmup requests to send before measuring (results excluded)	--warmup 5
-t, --timeout	Duration	No	Per-request timeout	-t 500ms
--retries	Integer	No	Number of retries on timeout before marking as failed	--retries 3
--no-redirect	Boolean	No	Disable following HTTP redirects	--no-redirect
-o, --output	Path	No	Write results to file. Format inferred from extension (.json, .csv)	-o report.json
--format	Text	No	Terminal output style (table, json, csv, silent)	--format table
--no-progress	Boolean	No	Hide the live progress bar	--no-progress
-v, --verbose	Boolean	No	Print each request result individually as it completes	-v
--insecure	Boolean	No	Skip TLS certificate verification	--insecure
--http2	Boolean	No	Force HTTP/2 (default negotiates)	--http2
--keep-alive	Boolean	No	Reuse TCP connections between requests	--keep-alive

---

Execution examples

# Basic GET with 500 requests and 20 workers
kload -u https://api.example.com/health -n 500 -c 20

# POST with body, 30s run, capped at 100 rps
kload -u https://api.example.com/login \
      -m POST \
      -H "Content-Type: application/json" \
      -b '{"user":"test","pass":"test"}' \
      -d 30s --rps 100

# Export results as JSON and no progress bar (CI mode)
kload -u https://api.example.com -n 1000 -c 50 \
      --no-progress -o results.json

Output example (console)

Output example (JSON)

{
  "total": 1000,
  "successful": 1000,
  "failed": 0,
  "req_per_sec": 1041.7580375278749,
  "total_duration_s": 0.9599158,
  "latency": {
    "max": "141.5ms",
    "mean": "23.5ms",
    "min": "15.4ms",
    "p50": "18.6ms",
    "p90": "24.0ms",
    "p95": "38.5ms",
    "p99": "137.0ms"
  },
  "status_codes": {
    "200": 1000
  }
}

---

Dependencies

No Dependencies! kload is completely dependency free and built in Go version 1.26.4.

---

License

MIT License

Copyright (c) 2026 KleeSup

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.