Volt

Terminal-native API development and performance testing for humans, AI agents, and CI

What's New • Installation • Quick Start • Interactive Load Testing • AI Agents and CI • Customization • Keybindings • CLI Mode

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Overview

Volt is a terminal-native API development and performance-testing system. Its interactive TUI makes requests easy to explore, while its composable CLI gives developers, coding agents, and CI jobs the same high-performance load engine for repeatable verification.

Volt is growing beyond a standalone TUI load tester into a workflow that can help teams develop an endpoint, verify it functionally, measure it under representative traffic, compare changes, and preserve evidence for review and production-readiness decisions.

What's new in v0.2.0

Volt is back and better than ever. The terminal interface now has a cohesive Controlled Voltage design, live YAML theme previews and persistent Settings, a two-second ASCII startup signature that compresses into a compact command center, and a redesigned load-testing workspace with live progress, metrics, and a rolling latency sparkline.

Read the complete v0.2.0 release notes.

Workflow	Best for	Interface
Interactive exploration	Creating requests and inspecting responses	volt TUI
Repeatable load tests	Local development and performance investigations	volt bench
Coding-agent verification	Measuring an API during implementation or review	Volt companion skill + CLI
CI evidence	Saving machine-readable results and detecting regressions	JSON output

Perfect for teams who:

• Live in the terminal and hate context switching
• Want Postman's features without the Electron bloat
• Love Vim keybindings and keyboard-driven workflows
• Need a fast, scriptable HTTP client with a focused UI
• Want a terminal interface with customizable semantic YAML themes
• Want live progress, latency, throughput, and failure signals during load tests
• Want coding agents to evaluate the APIs they build
• Want reproducible performance evidence in CI

Note: This is an active learning project. Performance optimizations are ongoing, and contributions/feedback are welcome :)

Volt includes default, terminal-aware adaptive, and no-color mono themes. Open ?, switch to SETTINGS with h/l, and use j/k to preview a theme across the entire interface. Saving persists the choice for the next launch. Custom themes are small semantic YAML files; see Themes and Customization for paths, examples, and safe fallback behavior.

Why Volt?

	Postman	Insomnia	HTTPie	curl	Volt
Terminal-native	❌	❌	✅	✅	✅
Interactive TUI	❌	❌	❌	❌	✅
Vim keybindings	❌	❌	❌	❌	✅
Syntax highlighting	✅	✅	✅	❌	✅
Save collections	✅	✅	❌	❌	✅
Zero install	❌	❌	❌	✅	✅
Memory footprint	~500MB	~300MB	~50MB	<5MB	~15MB
Startup time	~3s	~2s	<1s	instant	instant

Throughput comparison

No benchmark results are checked in yet. Generate a fresh comparison on the machine whose performance you want to document.

The comparison is generated from controlled local endpoints with pinned versions of Volt, wrk, hey, and k6. Docker is the only runtime dependency:

# Short integration check
make benchmark-smoke

# Five 10-second runs for every workload and concurrency level
make benchmark-comparison

Progress is written to stderr and the paste-ready Markdown section is written to stdout. Review a completed run, then replace the marked block above. To keep a dated copy without changing the command:

make benchmark-comparison > benchmarks/comparison-$(date +%F).md

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Installation

Volt is distributed as a single binary with no dependencies. The fastest way to install is using Go's built-in package manager.

Quick Install

If you have Go installed, you can install Volt with a single command:

go install github.com/owenHochwald/Volt/cmd/volt@latest # install
volt # run and verify

You should see the Volt TUI interface launch. Press Esc twice to quit. Updating Volt: To update to the latest version, simply run the install command again.

Troubleshooting: If you get a "command not found" error, ensure $GOPATH/bin is in your PATH:

# Add to your ~/.bashrc, ~/.zshrc, or equivalent
export PATH="$PATH:$(go env GOPATH)/bin"

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Quick Start

Once installed, launch Volt's interactive interface:

volt

Basic usage:

• Type a URL and press Alt+Enter (Option+Enter on macOS) to make a request
• Press Ctrl+L in the request panel to configure a load test
• Press ?, then use h/l to move between Help and Settings
• Use Ctrl+E and Ctrl+W to move between panels
• Press F1 anywhere to see every keybinding
• Press Esc twice to quit, or Ctrl+C to quit immediately

See the keybindings guide for every contextual shortcut and macOS Option-key setup.

Interactive Load Testing

Volt uses the same load engine in its TUI and CLI. In the request panel, press Ctrl+L, configure concurrency, total requests, an optional QPS limit, and a timeout, then focus RUN LOAD TEST or press Alt+Enter.

While the test runs, Volt prioritizes the results workspace and shows:

• Exact completed and total request counts with bounded progress
• Current throughput, p50 latency, and error rate
• A rolling interval-latency sparkline
• Explicit live, successful, and failed states

Use h/l or 1–3 in the response panel to inspect Overview, Latency, and Errors without interrupting live updates. Press Ctrl+X to cancel an active test.

AI Agents and CI

Volt's CLI is the tool-use interface for Codex, Claude Code, and other coding agents. An agent can construct an authenticated request, begin with a bounded smoke test, save JSON results, and report throughput, latency, status codes, and failures alongside the code change it made.

Start with Using Volt with AI coding agents. The portable volt-load-testing skill teaches agents when and how to use Volt, including authorization checks, staged load, secret handling, and before/after comparisons.

The current JSON output can also be saved as a CI artifact:

volt bench \
  -url http://127.0.0.1:8080/health \
  -c 10 \
  -d 30s \
  -rate 100 \
  -json \
  -o volt-results.json

Today, CI consumers must inspect the JSON result because HTTP request failures do not automatically make the Volt process exit nonzero. Stable assertions, exit codes, secret-safe inputs, scenario files, comparison reports, and CI-native output are planned as future milestones.

CLI Load Testing

Use the bench subcommand for non-interactive local, agent, and CI workflows.

volt bench [flags]

Examples

# Basic throughput test
volt bench -url http://localhost:8080 -c 100 -d 30s

# POST request with custom headers
volt bench -url http://localhost:8080/api -m POST \
  -b '{"test":true}' -H "Content-Type: application/json"

# JSON output to file for CI/CD
volt bench -url http://localhost:8080 -c 50 -d 60s -json -o results.json

# Rate-limited testing
volt bench -url http://localhost:8080 -c 10 -d 30s -rate 1000

# For help!
volt bench -h

License

This project is licensed under the Mozilla Public License 2.0 - see the LICENSE file for details.

Star History

If you find Volt useful, please consider giving it a star ⭐ on GitHub!

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