The Free Tools Stack Every Indie App Developer Should Bookmark

When you're a solo developer, your real budget isn't money — it's tabs. Every tool you have to pay for, learn, or babysit is friction between you and shipping. So this is the opposite of a bloated "100 tools" listicle: it's the free stack I actually keep bookmarked as an indie dev, organized so you can grab exactly the app store optimization tools you need and close the tab.

Everything here is free, browser-based, and built for the un-fun parts of launching an app solo — the screenshots, the ASO copy, the spec numbers, the growth math. Bookmark this page; it's the index. The whole set lives at Reverze's free tools.

Screenshots & store creative (the part that eats your week)

This is where most indie devs lose days. These handle the production so you don't:

• App Store Screenshot Checker — score your listing's first-frame clarity, text size, and consistency before you ship.
• Screenshot Size Converter — one master → every required App Store / Play size.
• Screenshot Crop & Resize and Screenshot Quality Analyzer — clean up and pressure-test each frame.
• Device Mockup Generator — drop your screen into a clean device frame.
• App Screenshot Background Remover and Image Compressor — prep source images without opening a heavy editor.
• App Icon Resizer — one 1024px icon → every iOS/macOS/Android size.
• App Store Preview Generator and Screenshot Text Extractor (OCR) — preview your listing and pull text out of any screenshot.

ASO copy & metadata (the words that convert)

The screenshots get the tap; the copy earns it. Free help for the writing:

• Screenshot Headline Generator and App Store Subtitle Generator — benefit-led captions and that all-important subtitle.
• App Store Keyword Generator — ASO keywords without a paid suite.
• ASO Metadata Preview, App Store Character Counter, and Word Counter — see and size your metadata before it's rejected for length.

Design & spec calculators (stop Googling the numbers)

The little numbers that break a build if you get them wrong:

• Aspect Ratio Calculator and Safe Area & Bleed Calculator — frame it right the first time.
• PX to PT Calculator and PPI Calculator — the unit conversions you always forget.
• Color Contrast Ratio Calculator and Font Size Scale Calculator — accessible, readable type and color.
• Image File Size Calculator and Golden Ratio Calculator — for the details that make it feel intentional.

Growth & analytics math (know your numbers)

You can't improve what you can't measure, and these free calculators mean you never need a spreadsheet template again:

• App Store Conversion Rate Calculator and Cost Per Install Calculator — the two numbers that decide if your launch works.
• LTV Calculator, CAC Calculator, and LTV:CAC Ratio Calculator — is your growth actually profitable?
• App Retention Rate Calculator, Churn Rate Calculator, and DAU/MAU Stickiness Calculator — are people staying?
• ARPU, MRR, and ROAS Calculator — revenue and ad-spend sanity checks.

A/B testing & experiments (test it, don't guess)

Before you run a Product Page Optimization test, do the math so it means something:

• A/B Test Sample Size Calculator and A/B Test Duration Calculator — how many installs and how long you actually need.
• A/B Test Significance Calculator and Conversion Rate Uplift Calculator — did the winner really win, or was it noise?

Planning & budget (before you build)

• App Development Cost Calculator and App Marketing Budget Calculator — rough the numbers before you commit.
• Break-Even Point Calculator and Profit Margin Calculator — the "is this worth it?" math.

How to actually use this stack

Don't bookmark all sixty. That's the mistake. Bookmark this page and the free tools hub, then pull the two or three you need for whatever you're shipping this week — a screenshot pass, a metadata check, a conversion-rate gut check — and ignore the rest until you need them. A stack you can find beats a stack you've collected.

And when the screenshot work outgrows one-off tools — when you're rebuilding a full set across sizes, languages, and every update — that's exactly what Reverze is for: paste your App Store URL and it rebuilds the whole campaign at once. The free tools handle the pieces; the app handles the pipeline.

Bookmark it. Ship the app. Come back for the next piece when you need it.

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Reverze is the AI-native studio for App Store creative — 60+ free tools plus a full rebuild-from-URL workflow. Explore the free tools or start in the app.