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If you want an Alumnium alternative that checks a coding agent's change from inside the running web app (requests, state, console) and replays it with no model in the loop, Reticle is built for that. If you want natural-language steps inside existing Selenium, Playwright or Appium suites, including real mobile apps, Alumnium is the better fit.
What Alumnium does
Alumnium describes itself as "End-to-End Testing with AI for Agents and Engineers" (alumnium.ai).
You mix natural-language steps into existing Selenium, Playwright or Appium tests from Python, TypeScript or Java clients. It also runs a local MCP server that Claude Code, Codex and Cursor use to drive and verify web or mobile apps (claude mcp add alumnium).
It is MIT-licensed with about 1,018 GitHub stars on 2026-10-25, and you pay only your model provider; Ollama is supported (GitHub). It is still alpha: the latest release on 2026-10-19 was 0.24.0-alpha.4.
What Reticle does
Reticle checks an AI coding agent's change and returns a pass or fail with evidence. It reads network calls, console, DOM and application state, and on React and Svelte it names the file:line to fix.
Your agent calls it over MCP from Claude Code, Cursor or Codex. Flows it drives are saved and replay deterministically. It works on your own app and on sites you don't own (its own browser, SDK injected); app state and file:line need the SDK in your build.
Alumnium vs Reticle at a glance
| Alumnium | Reticle | |
|---|---|---|
| What it reads | The page as an agent sees it, from outside | Inside the page: network, state, console, DOM |
| Fits into | Existing Selenium, Playwright, Appium suites | Your agent's loop, CI, the hosted platform |
| Mobile apps | iOS and Android through Appium | Web apps |
| Re-runs | A model interprets each step | Saved flows replay with no model, 0% flake over 8 replays |
| Points to the fix | The failing step | The failing request or state, and file:line on React and Svelte |
| Maturity | Alpha (0.24.0-alpha.4) | Released, with a published benchmark |
| Cost | Free (MIT) plus your model bill | Start free, no card; open-source SDK free |
Where Alumnium is the better choice
- You already have Selenium or Appium suites. Alumnium drops natural-language steps into them. Reticle is a separate tool.
- You test native mobile apps. Alumnium covers iOS and Android through Appium. Reticle is for the web.
- You want everything MIT and the option to run local models through Ollama.
- You want language choice: Python, TypeScript and Java clients.
Where Reticle is the better choice
- The failure never reaches the screen. A request fired twice or a store that disagrees with the page reads as fine to any tool that looks at the page. Reticle reads the network and state directly.
- You want re-runs without a model. Saved flows replay deterministically, so the same flow gives the same verdict, and re-verifying four flows costs about 480 tokens.
- You want the fix located. On React the verdict names the component and source line (on Svelte, the source line).
- You want a measured tool. 85 of 88 seeded bugs caught with no false alarms, method public in the scorecard.
Can you use both?
Yes. Alumnium can cover mobile and your existing Selenium suites, and Reticle can verify web changes from inside the app. For the wider field of MCP testing servers, see MCP browser testing. Why reading behaviour beats reading the page is in what AI verification is.
Every tool we compare is on the alternatives hub.
Try Reticle
Paste one line to your coding agent and it installs and wires the SDK:
Follow https://raw.githubusercontent.com/reticlehq/reticle/main/SKILL.md
Or run npx @reticlehq/core init. The README has the details.
FAQ
What is the best alternative to Alumnium?
The best alternative to Alumnium depends on what you test. For web apps where your coding agent needs a verdict from network, state and console inside the app, Reticle fits. For plain scripted tests, use Playwright or Selenium directly. For native mobile, Appium-based tools remain the main option.
Is Alumnium free?
Yes, Alumnium is free and open source under the MIT license, and you pay only your model provider, with local models through Ollama supported. It was in alpha at version 0.24.0-alpha.4 in October 2026. Reticle's SDK is also free and open source, under Apache-2.0.
How is Reticle different from Alumnium?
Reticle is different from Alumnium in what it reads and how it re-runs. Alumnium has a model interpret natural-language steps against the page. Reticle reads requests, state and console from inside the app, and replays saved flows deterministically with no model, giving the same verdict every run.
Does Reticle test mobile apps?
No, Reticle tests web apps, not native iOS or Android apps. It runs in the browser your web app runs in, on your own app or on sites you don't own. For native mobile, tools built on Appium, such as Alumnium, are the better choice today.
Why Reticle
Your agent says it works. Reticle checks.
- Checks each change inside the running app: network, state and console, not a screenshot.
- Returns a pass or fail with the evidence and the file:line to fix.
- Open-source SDK on your machine, or the platform on every preview and PR.
No credit card required.