whatisgithub

What is captcha?

moul/captcha — explained in plain English

Analysis updated 2026-07-17 · repo last pushed 2026-06-18

★ 13GoAudience · developerComplexity · 2/5ActiveSetup · easy

In one sentence

A command-line tool that generates text-based CAPTCHA puzzles, like math problems or ASCII art, to verify you're a real person right in your terminal.

Mindmap

mindmap
  root((repo))
    What it does
      Terminal CAPTCHAs
      Human verification
      No web images
    Tech stack
      Go
      CLI tool
    Use cases
      CLI auth checks
      Prevent bot abuse
      Experiment with CAPTCHAs
    Audience
      CLI developers
      Security tinkerers
    Engines
      Math puzzles
      ASCII banner text

Code map

Detail Auto

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filefunction / class

What do people build with it?

USE CASE 1

Add a human-verification check to a CLI tool without third-party services.

USE CASE 2

Challenge suspicious requests in a terminal application to prevent automated abuse.

USE CASE 3

Experiment with CAPTCHA mechanics for learning or fun.

USE CASE 4

Embed a lightweight text puzzle in any script you already run from the command line.

What is it built with?

Go

How does it compare?

moul/captchakleimer/vpn_over_sshroyp888/sola-bot
Stars131313
LanguageGoGoGo
Last pushed2026-06-18——
MaintenanceActive——
Setup difficultyeasyhardhard
Complexity2/54/54/5
Audiencedeveloperops devopsdeveloper

Figures from each repo's GitHub metadata at analysis time.

How do you get it running?

Difficulty · easy Time to first run · 5min

Copy-paste prompts

Prompt 1
Show me how to install and run moul/captcha to generate a math-based CAPTCHA.
Prompt 2
Help me integrate moul/captcha into my own CLI tool for human verification.
Prompt 3
Explain the difference between the math engine and banner engine in moul/captcha.
Prompt 4
Write a script that uses moul/captcha to block automated requests to my terminal app.

Frequently asked questions

What is captcha?

A command-line tool that generates text-based CAPTCHA puzzles, like math problems or ASCII art, to verify you're a real person right in your terminal.

What language is captcha written in?

Mainly Go. The stack also includes Go.

Is captcha actively maintained?

Active — commit in last 30 days (last push 2026-06-18).

How hard is captcha to set up?

Setup difficulty is rated easy, with roughly 5min to a first successful run.

Who is captcha for?

Mainly developer.

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