A few months ago, I was debugging a production API issue. I copied a JWT from our logs, pasted it into an "online decoder," and immediately felt sick.
I had just sent a live production token to a stranger's server.
That moment led to ToolsMania — a suite of developer and finance tools that run entirely in your browser. No server. No database. No data retention.
The Problem with "Free" Online Tools
Most online utilities are free because you are the product. Your inputs are logged, analyzed, and sometimes leaked. For developers handling:
- JWTs with production claims
- API keys and tokens
- Proprietary SQL queries
- Financial calculations with real numbers
...this is unacceptable.
What's Inside ToolsMania
For Developers
- SmartParser — Paste any mystery string. Auto-detects Base64, JWT, Hex, URL-encoding, JSON, XML, CSV.
- API Studio — A Postman alternative that runs in-browser. Import cURL, test endpoints, export code to Python/Node/Go/PHP.
- JWT Decoder — Instant payload inspection. Zero network requests.
- JSON Formatter — Interactive tree view, validation, minify/beautify.
- SQL Formatter — Supports MySQL, PostgreSQL, SQLite.
- Regex Tester — Real-time matching with plain-English explanations.
- Cron Generator — Next execution times in your timezone.
For Financial Planning
- Compound Interest Calculator — Interactive charts, year-by-year breakdown.
- Mortgage & Loan Calculators — Amortization schedules, extra payment analysis.
- EMI Calculator (India) — Tailored for Indian bank rates.
- Debt Payoff Planner — Avalanche vs. Snowball methods.
100% Client-Side Architecture
Every computation uses WebAssembly and modern browser APIs. When you close the tab, your data vanishes. We couldn't read it if we wanted to.
Try It
No signup required. No catch. Just tools that respect your privacy.
Have you ever accidentally leaked sensitive data to an online tool? Let's discuss in the comments.