Author & reviewerThe person behind the system
Islam Baraka.
Fintech Engineer — author and maintainer of the fintech builder.
I build financial software for a living and I write this library the way I wish finance had been explained to me as an engineer: from first principles, against primary sources, with working code. Every released article, every published glossary definition, and every Python and TypeScript implementation on this site is written, tested, and reviewed by me — there is no content team and no generated filler.
Why you can trust it
How every article is made.
Primary sources first
Each article ships with its reference trail: the sources behind every claim, the role each one plays as evidence, and — just as important — their stated limitations.
One canonical explanation
Every topic gets a single, complete write-up with explicit data contracts and assumptions, instead of scattered fragments that contradict each other.
Tested code in two languages
Each build includes dependency-light reference implementations in both Python and TypeScript. If the code doesn't run, the article doesn't ship.
A release contract
Article + sources + Python + TypeScript must clear the governed release state before public indexing, and every page keeps review and modification dates separate.
Public corrections
Found an error? Email ib@thefintechbuilder.com or open an issue on GitHub. Corrections update the modification record; a review date changes only after review.
What I write about
Engineering finance, domain by domain.
Freshly reviewed
Latest released builds.
Financial Mathematics, Statistics, and Data Foundations / Mathematical Language and Quantitative Reasoning
Variables, Constants, Expressions, and Equations
Learn to read a financial formula as a small sentence about money.Financial Mathematics, Statistics, and Data Foundations / Mathematical Language and Quantitative Reasoning
Functions, Domains, Ranges, and Graphs
See a function as a rule that turns an allowed input into one output.Financial Mathematics, Statistics, and Data Foundations / Mathematical Language and Quantitative Reasoning