hey vs Vegeta vs Siege for HTTP Load Testing

When engineers look for a lightweight HTTP load testing tool, three names show up again and again: hey, Vegeta, and Siege. All three are CLI-first tools. All three can generate HTTP traffic quickly. And all three appeal to developers who want something simpler than heavyweight frameworks.

But they are not interchangeable. hey is known for speed and simplicity. Vegeta is respected for its rate-based model and more disciplined reporting workflow. Siege is an older but still useful tool that many Linux users know from website or API pressure testing.

This guide compares hey, Vegeta, and Siege in the context of HTTP load testing in 2026. It explains where each tool shines, where the tradeoffs show up in practice, and when a team should consider a managed platform like LoadTester instead. For a broader CLI survey, see Best CLI HTTP Load Testing Tools in 2026. If you are considering whether a shell-only workflow belongs in CI, also read Is CLI HTTP Load Testing Enough for CI/CD?.

Overview

All three tools come from the same general tradition: they are small utilities that you can run from a shell, automate in scripts, and use during development or pre-release checks. That makes them attractive when you do not want to provision separate infrastructure or learn a more complex framework.

The danger is that teams often choose based on whatever tool they find in a blog post and never revisit whether it still fits. A command-line load test that is good enough for one engineer is not always good enough for a team that wants historical comparisons, clear thresholds, and shareable results.

Before choosing a tool, ask what question you are trying to answer. Do you just want to blast an endpoint quickly? Do you care about maintaining an exact request rate? Do you want to test a list of URLs? Do you need richer scenarios or CI/CD reporting? Those answers point toward different tools.

hey

hey is often the easiest to recommend when a developer wants something faster and cleaner than older tools. It is small, straightforward, and ideal for a quick check like this:

hey -n 1000 -c 50 https://api.example.com/users

You get a concise summary of request rates and latency, and you can see quickly whether an endpoint behaves reasonably under light concurrency. That makes hey attractive for smoke tests, quick experiments during development, or one-off checks in CI.

The advantage of hey is its simplicity. There is less syntax and less mental overhead than with some alternatives. If you want a minimal tool that gets to the point, it is excellent.

The downside is that hey remains deliberately simple. It is not designed to become a full performance workflow. It lacks the rate-based model and richer reporting flow that make Vegeta appealing for more disciplined CLI testing.

Vegeta

Vegeta is a favorite among engineers who want to keep the CLI workflow but care more about repeatability and rate control. Instead of only saying “run N requests with concurrency C,” Vegeta is built around a rate-based model. That is powerful because production traffic often resembles a sustained request rate more than a single concurrent blast.

echo "GET https://api.example.com/users" | vegeta attack -rate=200 -duration=30s | vegeta report

That rate-based design makes it easier to ask questions such as “can this endpoint sustain 200 requests per second for 30 seconds?” Vegeta also lets you save results and inspect them later, which is valuable when you want to compare runs or integrate the tool into a more repeatable process.

The tradeoff is that Vegeta is slightly less friendly to beginners than hey. It is still simple enough for most developers, but it has more concepts and flags. For many teams that structure is a benefit, not a drawback.

If your team values precision and can handle a slightly more structured workflow, Vegeta is often the strongest pure CLI choice of the three. If you want a direct comparison with a managed platform, continue with Vegeta vs LoadTester.

Siege

Siege is an older tool but still useful, especially in Linux-heavy environments. It is often used for simple website or HTTP endpoint testing with repeated requests and configurable concurrency.

siege -c50 -r10 https://api.example.com

Unlike Vegeta, Siege is not strongly centered around rate-based traffic. It feels more like classic concurrency testing. That can be enough when you just want to apply some pressure to a site or API and inspect overall behavior.

The benefits of Siege are familiarity and availability. Many engineers know it, and it remains easy to install. It can be useful for quick website checks or concurrency experiments in Linux environments.

The downside is that it feels more dated than hey or Vegeta and is not as pleasant for repeatable analysis. Like the other tools, it does not solve the collaboration and historical comparison problem that appears in real release workflows.

Feature comparison and practical fit

If you care most about ease of use, hey usually wins. It is quick to install, quick to understand, and perfectly adequate for a fast endpoint smoke test.

If you care most about rate control and repeatability, Vegeta is generally the strongest option. Its rate-based model is more useful for API testing, and its reporting flow scales better into serious CLI-based performance checks.

If you care most about simple concurrency testing with older, battle-tested tooling, Siege still has a place. It is especially familiar to administrators who have used it for website testing over many years.

All three are far better for ad hoc checks than for broader team workflows. None of them, by itself, gives you scheduled checks, rich dashboards, historical comparison across releases, or easy collaboration.

Are they enough for CI/CD?

They can be, but “can run in CI” is not the same as “provides useful release confidence.” A small hey or Vegeta command can run in a pipeline and fail the build if latency or error rates cross a threshold. That is a good start.

The problem is that pipeline logs are not dashboards, and a single pass/fail result is not the same thing as a performance practice. Over time, teams want to compare current latency with past baselines, inspect percentiles, and share results with teammates.

If your team is seriously integrating performance checks into CI/CD, read Load Testing in CI/CD and Is CLI HTTP Load Testing Enough for CI/CD?.

Where LoadTester fits

LoadTester is useful when the team has moved beyond the “one engineer with a shell command” stage. It lets teams run application and HTTP load tests without managing infrastructure, inspect live metrics, and compare results across runs. That makes it much easier to use performance checks as part of real release decisions.

The point is not that CLI tools are bad. They are often the fastest way to ask a narrow question. The point is that once your organization wants scheduled checks, dashboards, shared visibility, and easier historical comparison, a managed workflow saves time and avoids accidental complexity.

For example, with LoadTester you can give teammates a single place to view results instead of pasting terminal output into chat. You can define thresholds, rerun tests consistently, and see whether p95 and p99 latencies are drifting in the wrong direction over time.

Which one should you choose?

Choose hey if your goal is the quickest possible smoke test and you value minimal syntax.

Choose Vegeta if you want more disciplined rate-based testing and a CLI workflow that scales better into serious performance checks.

Choose Siege if you are comfortable with older concurrency-oriented tooling and want a simple way to pressure-test endpoints or websites.

Choose LoadTester if your team needs more than ad hoc CLI commands and wants shareable dashboards, live metrics, and repeatable release confidence.

FAQ

Is hey better than Vegeta?

It is simpler, but not necessarily better. hey is a great quick-check tool. Vegeta is usually stronger when rate control and repeatability matter.

Is Siege still useful?

Yes, especially for concurrency-oriented testing and older Linux-based workflows, but it feels more dated and is less flexible than some newer options.

Which one is easiest for beginners?

hey is usually the easiest to learn because the interface is minimal and the output is easy to interpret.

Should I use one of these in CI/CD?

You can, but they are best for basic checks. Teams that want historical reporting, scheduled checks, and shareable results often move to a managed workflow.

Final thoughts

hey, Vegeta, and Siege all remain relevant because there are still many situations where a shell-based HTTP load test is exactly the right tool. The key is to choose based on the real use case rather than package-manager popularity.

For quick smoke tests, hey is a great choice. For more disciplined rate-based testing, Vegeta is often the strongest pick. For older concurrency-oriented workflows, Siege remains serviceable. And when those workflows are no longer enough to give your team real confidence, LoadTester is worth trying as the next step.