Fortio

Overview

Fortio is a Go-based toolkit for HTTP and gRPC load testing, with a command-line interface, server, and web UI. It is best suited to developers and teams who want control over where tests run or need load-testing components they can embed in Go software. Its combination of rate-controlled runs, percentile reporting, and server utilities makes it a capable self-hosted choice, though it calls for teams to operate the tooling themselves.

Key features

Fortio can run at a target query rate or maximum speed, for a chosen duration, a fixed number of calls, or until interrupted. It records latency histograms and percentiles such as p99, giving teams a way to examine both the load they generated and how response times are distributed. The range of run modes is useful for repeatable tests and open-ended checks, but teams must decide how to run and interpret those tests.

The included server offers a web UI and REST API for starting runs and viewing latency and comparative result graphs. That gives users both a browser-based route and a programmatic one without separating the test runner from its reporting interface.

Beyond load generation, Fortio includes request echo, probabilistic latency and error injection, TCP echo and proxy, HTTP fan-out proxy, and gRPC echo and health features. These utilities can help teams exercise and debug services as well as generate traffic. Fortio is also reusable as a Go library; its log, stats, and fhttp components can be used independently, which makes it a stronger fit for Go-centric workflows than for teams seeking a standalone managed service.

Fortiotel adds OpenTelemetry hooks and defaults as a Fortio variant. Fortio Proxy can provide HTTPS with automatic TLS certificates and multiplex gRPC and regular HTTP services behind one port. These are useful adjacent capabilities, but they do not change the product’s self-hosted operating model.

Pricing

Fortio — free. The open-source plan includes downloadable binaries, a Docker image, and a self-hosted CLI, server, and web UI. There is no free trial because the product is free. This is a straightforward option for teams able to run the software themselves; it does not come with a hosted deployment plan.

Installation options include Docker, Go install, platform binaries, Homebrew on macOS, and a Windows ZIP. Building from source requires Go 1.18 or later. The published Docker image supports linux/amd64, linux/arm64, linux/ppc64le, and linux/s390x.

Platforms

Fortio is listed for API, Linux, macOS, self-hosted, web, and Windows use. The range of installation routes covers common developer environments, while its on-premise deployment model keeps execution under the team’s control.

Who it's for

Fortio is a good fit for developers who need HTTP or gRPC load testing with percentile-based latency reporting, teams that want an API or web UI to start and compare runs, and Go developers who want to embed testing or reuse individual components. It is less suitable for organizations looking for a hosted testing platform or a managed service rather than software to install and operate.

The project directs users to GitHub for examples, releases, issue reporting, and contributions. Its security policy asks users to open an issue or contact the main author to report a vulnerability.

Pros and cons

• Pros: Free, open-source access to the CLI, server, web UI, and Docker image avoids a paid plan barrier.
• Pros: Target-QPS and maximum-speed runs, with duration or call-count controls, accommodate several testing patterns.
• Pros: Histograms, percentile measurements, comparative graphs, and a REST API support both analysis and automation.
• Pros: Echo, proxy, and fault-injection utilities extend its usefulness beyond generating load.
• Pros: Embeddable Go libraries and independently reusable components suit teams building around Go.
• Cons: Fortio is self-hosted, so teams must run the CLI or server rather than rely on a hosted deployment.
• Cons: Source installation requires Go 1.18 or later, a consideration for teams that prefer not to manage a Go toolchain.

Alternatives

Browse Performance Testing Software for more options. Consider Artillery if a freemium product with a free trial and a paid Team plan is a better fit; its Team plan is $199 a month and includes 1,000 reports per month, six months of data retention, eight team members, and up to 25 workers per distributed test. Locust is another free option, with an open-source MIT license, for readers comparing self-hosted load-testing tools.

Speedscale is worth considering when its free proxymock plan’s local mocking and traffic-recording features suit the work. Taurus offers a free and open-source option under the Apache 2.0 license. Apache JMeter is another free open-source choice, but requires Java 8 or later.

Grafana k6 may suit readers looking for a freemium alternative with a free tier capped at 500 virtual user hours per month. Loader.io is an option for readers whose needs fit its free plan: 10,000 clients per test, one target host, one-minute tests, and two URLs per test. LoadFocus has a free API Monitoring plan with 10,000 checks per month, five-minute check frequency, one-month data retention, and SSL certificate monitoring.

Verdict

Choose Fortio if you want free, open-source HTTP and gRPC load testing that you can run on your own infrastructure, inspect through a web UI or API, and extend with Go libraries. Its reporting and server utilities make it more than a basic traffic generator. Look elsewhere if your priority is a hosted platform or you do not want to manage the testing software yourself.