Our story

Paste the code, get the obvious bugs pointed out. No account, no repo access.

I'm Johnny Mobley. I started building systems for other people in 2000, when I was 16, and I've been doing it ever since. Along the way I automated most of my own work, and the tools I built for myself became these companies. Each one runs on rules I wrote down, not on paid AI calls, which is why it can cost so little.

Most code-review tools want to be installed on your repository and billed per developer. Sometimes you just have one function, or one error message, and you want a second pair of eyes before you commit. DevDucky is that: paste the code or the error and read the answer.

Both halves run on rules I wrote down: a list of known defect patterns (eval on user input, SQL built from strings, and so on) and a table of common error messages with their usual causes. It finds what's on that list and says so plainly; it doesn't understand your program's logic, and it tells you that in every answer.

What works today

• Reviews pasted code for known bug and security patterns, such as eval() on input or SQL built by joining strings, and lists each one by line and severity
• Takes an error message (and optionally the code around it) and gives the likely cause and a concrete fix
• Says in each answer that it runs on hand-written rules, not an AI model

What it doesn't do yet

CodeRabbit still does things DevDucky doesn't:

• Reviewing pull requests automatically inside GitHub or GitLab. DevDucky reviews what you paste.
• Understanding what your program is meant to do. It only matches known defect patterns.
• One-click fixes applied to your code.
• Learning your team's own conventions from past reviews.

What it costs

CodeRabbit's price is from their pricing page as of October 29, 2026. Prices change, so check theirs before you compare.

— Johnny