2026-02-17 A vibe-coded alternative to YieldGimp

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 of the tradable low-coupon gilts.

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/, and the source is on GitHub.

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 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.