# A vibe-coded alternative to YieldGimp

> Source: <https://mazzo.li/posts/vibe-coded-gilts.html>
> Published: 2026-07-20 16:45:23+00:00

If you’re a UK tax resident, short-term low-coupon gilts are the most tax efficient way to get savings-account-like returns, since most of their yield is tax free. This makes them very popular amongst retail investors, which now [hold a large portion](https://archive.is/cEUtf) of the tradable low-coupon gilts.

[YieldGimp.com](http://YieldGimp.com) used to be a great free resource to evaluate the gilts currently available. However, it was recently turned into an app rather than a simple webpage. I’m not even sure if the app is free or paid, but I do not want to install the “YieldGimp platform” to quickly check gilt metrics when I buy them.

So I asked my LLM of choice to produce an alternative, and after a few minutes and a few rounds of prompting I had something that served my needs. It is available for use at [mazzo.li/gilts/](https://mazzo.li/gilts/), and the source is [on GitHub](https://github.com/bitonic/gilts-app).

It differs from YieldGimp in that it does not show metrics based on the current market price, but rather requires the user to input a price. I find this more useful anyway, since gilts are somewhat illiquid on my broker, so I need to come up with a limit price myself, which means that I want to know what the yield is at my price rather than the market price. It also lets you select a specific tax rate to produce a “gross equivalent” yield.

It is not a very sophisticated tool and it doesn’t pretend to model gilts and their tax implications precisely (the repository’s [README](https://github.com/bitonic/gilts-app/blob/master/README.md#yield-model-used) has more details on its shortcomings), but for most use cases it should be informative enough to sanity-check your trades without a Bloomberg terminal.
