About us

Ever wondered how we, at 1st Money, keep our software so reliable? In short, we do it by every day: 

• Exactly matching all 4,300 of HMRC's model tax calculations, 
• Publishing 189 product videos, 
• Running over 4,000 click-navs, 
• Checking over 21,000 asserts, 
• And running over 1,000 delves. 

This videos numbers are up-to-date as of the 17th of March, 2023. Keep watching, to see how this all works. 

Tax scenarios

Tax scenarios. We test our tax calculations by inventing 15 different imaginary taxpayers, shown (at the top of the screen). 

Each one has different settings. For example, how many hours the imaginary taxpayer works, how much is paid, whether the imaginary taxpayer's married, whether there's children, and much more. We use our 15 different imaginary taxpayers to exactly match all 4,300 of HMRC's model tax calculations. 

Each tax calculation is matched to the penny, giving us recognition from HMRC that our tax software is 100% correct. And, of course, we sit down and re-verify them all with HMRC every year. 

Product videos

Product videos. So far, we've made 189 tutorial videos, explaining every part of the 1st Money product. 

Everywhere in the 1st Money product, you'll find video buttons . When you click one, a video pops out from the side. In our help pages, almost every sentence can be clicked on to show a video explaining that step. 

To make this all work perfectly, we've built our own video player, and video creation software. This way any customer that wants help can immediately find answers. 

Elements

Elements. To make our software look beautiful on both laptops and smartphones, we've built our own library of 40 software widgets. Each widget has its own testing page, showing the different ways it can be used. This lets us easily spot if any of the elements has any errors. 

Click-navs

Click tests. Every night, we use robots to do 9,000 clicks through the 1st Money product on 4,000 pathways. This pushes our test server's 8-core CPU to 100% for over 7 hours straight. 

On each pathway, a tiny robot clicks a different path through the 1st Money product as fast as the CPU allows. It's just like you're seeing on-screen right now. If the robot spots anything wrong, it takes some screenshots and writes some notes about the error. Using the error notes, our developers then make fixes. 

This way, bugs are usually spotted by us first, and not by our customers. 

Developer tools

Developer tools. At 1st Money, all our developers use specialised developer tools for their day-to-day programming. 

Every time a developer finishes making changes to the software, the developer tools analyze the code the developer's written. This warns the developer about errors like missing functions, unused variables, and much more. 

TypeScript

TypeScript. Every developer, twice a day, runs a script that compiles all 200 of our TypeScript files, and then scans them with ESLint. We use TypeScript to make sure any JavaScript errors get caught by us first, and not by our customers. 

Unit tests

Unit tests. Every developer, twice a day, runs thousands of asserts to test our software. This includes 7,000 tax asserts, and 15,000 system asserts. 

Each dot you can see on the screen represents about twenty asserts. Altogether, the 21,000 asserts take about 1 minute to run. This makes sure that day-to-day software changes don't accidentally break our existing code. 

Delves

Delves. Every developer, twice a day, runs 1,000 code checks, taking about 1 minute for the entire set. The code checks scan the 6,000 files in our codebase, looking for things to improve in the code, including: 

• Code that's too complicated, 
• Things that need to be named more clearly, 
• And much more. 

This way, each day's changes are continuously scrubbed clean. 

Confirm URLs

Confirm URLs. Every developer, twice a day, runs a spider that automatically opens and tests a sample of over 400 pages, spread across 1st Money's entire system. It takes about 1 minute each time, to test them all. 

This helps make sure that obvious problems like dead links or page-load errors are caught by us first, and not by our customers. 

Documentation quality

Documentation quality. Every developer, twice a day, runs a script that scans all our documentation and help, searching for sentences that can be improved. We check for things like: 

• Spelling, 
• Abbreviations, 
• Sentences that're too long, 
• And much more. 

We hope you love it!

And that's it! That's everything you need to know about how we keep our software reliable at 1st Money. We've loved building it, and hope you love it too!