---
title: "Play with your errors"
url: https://erroneo.us/tools/
description: "Free interactive tools: a proofreading game, a bias-or-fallacy quiz, a JS and Python error decoder, an HTTP status code explorer and myth-or-fact cards."
type: tool-index
section: "Play"
date_modified: 2026-10-20
publisher: erroneo.us
license: All rights reserved. Quote with attribution and a link.
---

# Play with your errors

> Reading about mistakes is useful. Catching them yourself sticks. Every tool here is built on the same sourced guides, runs entirely in your browser, and needs no sign-up.

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## Spot the Error

Timed rounds of sentences with one mistake. Tap the wrong word before the red pen does.](https://erroneo.us/spot-the-error/)
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## HTTP Status Code Explorer

Every registered code, searchable by number, class or keyword, with what to do next.](https://erroneo.us/developers/http-status-codes/#status-code-explorer)
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## Bias or Fallacy?

Everyday scenarios. Name the cognitive bias or logical fallacy hiding inside.](https://erroneo.us/bias-or-fallacy-quiz/)
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## Error Message Decoder

Paste a JavaScript or Python error. Get the plain-English meaning and the fix.](https://erroneo.us/error-decoder/)
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## Myth or Fact?

Swipe through popular claims. Every verdict is backed by a cited source.](https://erroneo.us/myths/#myth-or-fact)

## Built on the guides, not instead of them

Each tool is a doorway into the reference. Every game answer, quiz explanation, decoded error and myth verdict links to the section of the guide that explains it, and every guide links to its sources. If something here looks wrong, it probably is wrong in a guide too, and our [corrections policy](https://erroneo.us/about/#corrections) applies to both.

## Private by design

Nothing you type, paste or tap is sent to a server. Best scores and your colour theme are kept in your own browser’s local storage, and you can clear them like any other site data.

## Keyboard shortcuts

- ⌘ K or Ctrl K (or /) opens search over every guide, on every page.
- Games and quizzes are fully playable with Tab, Enter, number keys and arrow keys.
- There is at least one more shortcut. It involves arrows. We’ll say no more.

---
Source page: https://erroneo.us/tools/ · More: https://erroneo.us/llms.txt