Hi everyone,

I'm the solo developer behind Easy Work Calculator, which has grown into a collection of 400+ calculators and utility tools.

Rather than promoting it, I thought I'd share some engineering decisions that made maintaining hundreds of tools manageable.

1. Every calculator follows the same architecture

Each calculator is treated as a small module with:

• Input schema
• Validation rules
• Calculation engine
• Result formatter
• SEO metadata

Keeping the calculation logic independent from the UI has made it much easier to maintain and test.

2. Shared calculation engine

Many calculators seem unique but actually reuse the same underlying logic.

For example:

• Percentage increase/decrease
• Profit & loss
• Discount
• Margin
• ROI

They all share common mathematical functions instead of duplicating code.

3. Browser-first approach

Whenever possible, calculations happen entirely on the client.

Benefits:

• Faster responses
• No API costs
• Better privacy
• Offline-friendly
• Easier scaling

4. One design system

Every calculator uses the same reusable components for:

• Inputs
• Validation
• Results
• Copy/share actions
• Export functionality

That consistency significantly reduced development time.

5. Categories become important

Once you reach a few hundred tools, discoverability becomes harder than building new calculators.

I've spent more time improving search, categorization, and navigation than writing calculation formulas.

6. Small tools create edge cases

The calculations are usually simple.

The difficult part is handling:

• Invalid input
• Localization
• Floating-point precision
• Unit conversions
• Mobile UX
• Accessibility

Those often take longer than implementing the actual formula.

7. Performance matters

Hundreds of pages forced me to think carefully about:

• Code splitting
• Lazy loading
• Shared components
• Bundle size
• SEO
• Core Web Vitals

Small improvements multiplied across hundreds of pages make a noticeable difference.

I'm currently expanding beyond traditional calculators into more developer-focused utilities such as JSON formatters, regex testers, JWT tools, API helpers, and similar utilities.

I'd love feedback from developers who have built large collections of small tools.

• How do you organize reusable logic?
• How do you avoid duplicated code?
• What tooling has saved you the most maintenance over time?

If anyone wants to discuss architecture or implementation details, I'm happy to answer.

Project:
🌐 https://easyworkcalcs.com

Android:
📱 https://play.google.com/store/apps/details?id=com.xylemsoft.ewc