I used to pay $120/year for a SaaS that hasn’t added new features in four years, and didn’t fix its broken billing system for three years. Using an LLM, I managed to rewrite all the functionality I used to pay for in 20 minutes. Is this bad news for “write once, don’t update later” SaaS?

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A developer replaced a $120/year testimonials SaaS (Shoutout.io) in 20 minutes using an LLM (Codex) after the service's billing system broke. The replacement involved storing testimonials in JSON and generating HTML at build time. While rebuilding the entire SaaS would be much harder, replacing a specific use case proved surprisingly easy. This suggests that SaaS products providing no ongoing value or maintenance are vulnerable to LLM-powered replacements, especially when customers encounter broken features. However, developers have a significant advantage in this process compared to non-technical users who may struggle with command-line workflows and code verification.

I replaced a $120/year micro-SaaS in 20 minutes with LLM-generated code

What does this mean for SaaS products and software engineers?

I share the same reservation regarding compliance etc. Useful software is more than just a UI for CRUD. In my experience even big companies who live and breathe (and most importantly sell) software do not successfully maintain internal tools unless critical for the business. You get a half-assed version that nobody maintains and becomes less and less useful over time. (Of course, sometimes you get unmaintained solutions for mission critical software too. That’s worse.)
Tbh I don’t understand the selling point for the testimonials SaaS. It just renders a few rectangles that have to be administered manually? How does this differ from any other content? Also I clicked on a few. Most X/Twitter links were dead and the like counters were also mostly wrong. So not sure what I should take away from that section.

And who will maintain it, keep it up to date lol?

It’s quite simple: any SaaS that relies on use cases or foundational elements a LLM cannot replicate will be safe. For example, massive business data sets.

No original feature was small in the beginning. I wonder why he used such a feature when it was just a section on the website, something that can be easily changed with some Html and js.

its scary what few minutes of vibe coding can make