Browser UI

A full-featured, zero-build Single Page Application for interactive load testing.

Overview

Overload comes with a beautiful vanilla JS web interface built on top of a FastAPI backend. It allows you to configure, execute, and monitor load tests visually.

To start the UI, simply run:

overload ui

This will start the local server and automatically open http://localhost:3000 in your browser.

Key Features

• Auto-discovery: Automatically detects Postman collections, environment files, and CSV data files in your current working directory.
• Live Dashboard: Real-time Chart.js visualisations for RPS, error rates, and latency distribution using WebSockets.
• Beginner Mode: Toggle a "Beginner mode" button to show plain-English sub-labels under each KPI card. State is persisted across sessions in localStorage.
• Visual Configuration: Intuitive sliders and inputs for configuring all 10 load testing patterns, with a traffic-shape preview mini-chart.
• Request Selection: Per-request checkboxes in the collection tree, folder checkboxes with indeterminate state, Select All / Select None, and a live counter. Only checked requests are included in the run. Leaving all checked runs the whole collection.
• CSV Data Files: Drag-and-drop or upload a CSV file to drive parametric testing. The UI shows which {{placeholders}} matched columns (green) and which didn't (amber).
• Assertions Editor: Add and remove pass/fail conditions interactively before starting a test.
• Save/Load Config: Write current test settings to overload.config.yaml for CLI/CI reuse. Load a saved config to restore settings.
• In-app Docs: A full documentation tab built into the UI — no browser navigation needed. 8 topics with client-side routing.
• Run History: Past runs persist across restarts — the Results tab scans reports/ on load to restore history.

1. Collection View

The first screen is the Collection View. Here you can:

• Load a Postman Collection and optional Environment file (drag-and-drop or auto-detected).
• Browse the request tree — folders expand/collapse; click a request to see its URL, headers, body, and auth.
• Check/uncheck individual requests or whole folders to run only a subset. A counter shows "N of M selected".
• Attach a CSV data file for data-driven testing. The panel shows matched and unmatched placeholders.
• Override collection variables inline via the variable table.
• Click Continue to proceed to the Runner.

2. Test Runner View

The Runner View is the control panel for your test. You can:

• Select from 10 test patterns (Burst, Load, Stress, Spike, Soak, Ramp, Breakpoint, Custom, Rate Limit — Sequential is a separate CLI subcommand).
• Tune parameters for the selected pattern — concurrency, RPS, duration, stages, etc.
• Watch a traffic-shape mini-chart update live as you adjust parameters.
• Configure assertions and save/load config files.
• Toggle Save response bodies to capture the first 10 KB of each response into responses.json.
• Toggle Beginner mode for plain-English phase descriptions and KPI hints.
• Click Start Test. The view transitions to a live dashboard.

Live Dashboard

While a test is running, the Runner view shows:

• 6 KPI cards: Total, Success, Avg Latency, Current RPS, Elapsed, Errors — each with a ? tooltip and optional beginner hint.
• Real-time RPS chart and latency chart (Chart.js, updated every ~0.5 s via WebSocket).
• Phase label and a human-readable phase description below the progress bar.
• A scrolling request log showing the 100 most recent requests with status badges.
• Stop button — signals the pattern to finish cleanly within 10 seconds. A partial HTML report is always generated.
• After completion or stop: button changes to View Results. A PASS/FAIL verdict banner appears if assertions were configured.

3. Results View

The Results View shows a table of all runs — including previous runs restored from disk on startup. For each complete or stopped run:

• Run ID, test type, status, verdict (PASS/FAIL badge), total/ok/error counts, avg RPS.
• HTML Report — opens the full report in a new tab.
• Responses — appears when response bodies were saved; downloads responses.json.
• Details — expands an inline panel showing the full stats JSON and per-assertion verdict breakdown.

4. Docs Tab

The built-in Docs tab provides offline-accessible documentation covering all 10 test patterns, assertion metrics, CSV data testing, authentication, CI/CD integration, and more — all rendered client-side without leaving the app.