DEV Community: Trade Craft

Designing a Precision Risk and Lot Size Calculator for Prop Firm Traded Accounts

Trade Craft — Tue, 30 Jun 2026 14:32:50 +0000

Many Forex traders blow their funded accounts not because of poor entry signals, but because of simple mathematical errors in lot-size calculations. With daily drawdown limits of 4-5% enforced strictly by major prop firms, even a tiny oversight can lead to an immediate breach

To protect my own capital and help other traders, I designed and built a client-side lot size and risk calculator optimized for high-leverage prop firm accounts

THE ENGINE AND THE MATHEMATICS
Unlike standard calculators that just look at stop-loss distance, this calculator dynamically processes:

Live account equity and balance variations
Dynamic daily drawdown limits (calculating the exact buffer left before a hard violation)
Custom leverage and broker commission impact

By running all mathematical logic client-side within a highly reactive frontend, the calculations occur instantaneously without any server roundtrips, allowing traders to adjust their parameters in milliseconds

MINIMALIST DARK MODE UI
For traders managing high-frequency setups, UI clutter is a massive distraction. The application features a high-contrast, dark-mode-first aesthetic inspired by Linear and Vercel. We utilized geometric sans-serif typography (Geist and Inter) and monospace styling for numbers to ensure maximum readability under stress

Stop guessing your trade sizes and risking your funded accounts. You can run your calculations instantly with the tool here:
prop-calc.bete.poke.site

How I Built a Multilingual Prop Firm Comparison Engine with TanStack Start and Programmatic SEO

Trade Craft — Tue, 30 Jun 2026 14:30:53 +0000

As a developer and algorithmic trader, I got tired of wading through biased affiliate blogs and outdated Google Sheets just to compare Forex prop firm rules. To solve this, I built a lightning-fast, multilingual comparison tool that handles real-time drawdown metrics and specs for top firms like FTMO, The5ers, and E8 Markets

Here is a breakdown of the technical decisions and architecture behind it

THE TECH STACK

Frontend Framework: TanStack Start (React, Vite, and TanStack Router for robust file-based routing)
Styling: Tailwind CSS v4 (offering ultra-fast compile times and custom CSS custom properties)
Deployment: High-speed, edge-optimized hosting on a lightweight sandbox environment

HANDLING INTERNATIONALIZATION AND DYNAMIC PSEO
To capture search traffic from global traders, the app runs on a dynamic Programmatic SEO (PSEO) engine. The router maps localized sub-paths for 14 different languages to generate dynamic matchup pages on the fly.

The main challenge was managing structural SEO routing without sacrificing performance. By using TanStack Router's loader APIs, we prefetch firm metrics and render highly-cached comparison tables, ensuring near-instantaneous page loads

To keep search rankings high, we also implement a dynamic sitemap generation system that updates automatically whenever we adjust a firm's specs

Want to see how it performs in production? Check out the live comparison engine here:
prop-compare.bete.poke.site