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// the tools

Everything a dev needs,
ready instantly

All tools run entirely client-side — your data never leaves your machine.

⇄
conversion ↗

JSON to CSV

Paste any JSON array and instantly download a clean CSV. Handles nested objects, custom delimiters and large datasets.
❐
formatting ↗

SQL Formatter

Beautify messy SQL queries with proper indentation, keyword casing and clause alignment. Supports MySQL, PostgreSQL and SQLite.
.*
testing ↗

Regex Tester

Write and test regular expressions with live match highlighting, capture group inspection and named group support.
⏱
scheduling ↗

Crontab Generator

Build cron expressions visually or parse existing ones into plain English. Includes next-run previews and common presets.

// why dev helper

Built for developers,
by developers

No bloat. No ads. No paywalls. Just tools that work.

🔒

100% client-side

All processing happens in your browser. Your code, data and queries never touch our servers.

⚡

Instant results

No round-trips, no loading states. Results appear as you type, every time.

📋

Copy & download

Every output can be copied to clipboard or downloaded as a file with one click.

📱

Works everywhere

Fully responsive — use Dev Helper on desktop, tablet or mobile without losing functionality.

🚫

No account needed

Jump straight in. No email, no password, no cookie banners for tracking.

🎨

Clean interface

Designed to get out of your way so you can focus on the work, not the tool.

// faq

Common questions

Everything you need to know about Dev Helper.

Is my data safe when using these tools?
Yes. Every tool on Dev Helper runs entirely in your browser using JavaScript. Nothing you paste or type is sent to our servers. Your SQL queries, JSON data, regex patterns and cron expressions stay on your machine.
How do I convert JSON to CSV?
Paste or upload your JSON array into the JSON to CSV tool. The converter will automatically detect the keys, flatten nested objects, and produce a properly escaped CSV. You can then copy the output or download it as a .csv file.
Which SQL dialects does the formatter support?
The SQL formatter works with standard SQL and is compatible with MySQL, PostgreSQL, SQLite and Microsoft SQL Server syntax. It handles SELECT, INSERT, UPDATE, DELETE, CREATE TABLE, JOIN clauses and subqueries.
What regex flavour does the tester use?
The regex tester uses JavaScript's built-in RegExp engine, which supports all standard regex features including lookaheads, lookbehinds, named capture groups, and Unicode properties. Flags (g, i, m, s, u) are all supported.
How do I read a crontab expression?
A crontab expression has five fields: minute (0–59), hour (0–23), day of month (1–31), month (1–12), and day of week (0–7, where both 0 and 7 are Sunday). Paste an existing expression into the Crontab Generator to get a plain-English description and see the next scheduled run times.