23 free developer tools · zero uploads · browser-only
Developer tools: JSON, regex, Base64, UUID and more.
A curated set of 23 browser-based developer utilities pulled from our File Conversion category: JSON formatting and validation, regex testing, UUID and password generation, Base64 and URL encoding, hashing, a JWT decoder, a CSS minifier, and converters that turn JSON into Dart models or HTML into Flutter widgets. Every tool runs locally, with zero uploads and no account.
- Files never leave your device
- No account needed
- Free to use
The catalog
23 developer tools, in one place
Every tool below opens at its usual File Conversion URL - this page is just a faster way to find them.
JSON Formatter / Validator
Pretty-print, minify, and validate JSON.
Base64 Encoder/Decoder
Encode text to Base64, or decode Base64 back to text.
Hash Generator (MD5/SHA-256)
Generate an MD5 or SHA-256 hash from text or a file.
UUID Generator
Generate one or more random UUIDs (v4).
Password Generator
Generate a strong, random password.
Regex Tester
Test a regular expression against sample text.
URL Encoder/Decoder
Encode or decode text for safe use in a URL.
Markdown ↔ HTML Converter
Convert Markdown to HTML, or HTML back to Markdown.
JSON to Dart
Convert JSON into a real, compilable null-safe Dart model class with fromJson/toJson.
HTML to Flutter
Convert an HTML snippet into a Flutter widget tree, pretty-printed as real Dart.
CSS Minifier
Minify CSS correctly: strips comments and whitespace without breaking calc(), nesting, or custom properties.
JWT Decoder
Decode a JSON Web Token to view its header and payload.
Meta Tag Generator
Generate title, description, Open Graph, and Twitter Card meta tags.
Cron Expression Builder
Build and understand cron expressions with a plain-English explanation.
HTML Entity Encoder / Decoder
Encode text to HTML entities or decode entities back to text.
Subnet Calculator
Calculate network address, broadcast address, and host range from CIDR.
URL Parser
Break a URL down into its protocol, host, path, and query parameters.
Number Base Converter
Convert numbers between binary, octal, decimal, and hexadecimal.
Roman Numeral Converter
Convert between Roman numerals and regular numbers, both directions.
GCD / LCM Calculator
Find the greatest common divisor and least common multiple of numbers.
Prime Number Checker
Check if a number is prime and see its prime factorization.
Quadratic Equation Solver
Solve ax squared plus bx plus c equals 0 for real or complex roots.
Ohm's Law Calculator
Calculate voltage, current, resistance, or power from any two values.
Why use it
Built the same way as every other Slaytic tool
- 01
100% private
Every tool processes your input using JavaScript inside your browser tab. Nothing is ever uploaded to a server.
- 02
Instant results
No upload wait, no queue. Formatting, testing, encoding and generating all happen the moment you type.
- 03
Always free
No account, no trial, no limits. Every developer tool is free to use without restriction.
Questions
Before you dive in
Are these the same tools as the ones under File Conversion?
Yes. This page is a curated shortcut to the developer-focused tools inside the File Conversion category, at the exact same URLs. Nothing is duplicated - it just groups them by "for developers" instead of by file format.
Are all 23 developer tools free?
Yes. All 23 tools here are completely free with no limits, no premium tier, and no account required.
Does any tool here upload my data to a server?
No. Every tool runs entirely in your browser using JavaScript - JSON you paste, regex you test, files you hash, all of it stays on your device.
Can I use these tools for large inputs?
Yes for most inputs. A few tools (like Regex Tester) cap extremely large inputs or match counts to keep the tab responsive, since everything runs on your device rather than a server.
Built for developers
Open a tool and get started.
JSON, regex, UUIDs, Base64 and more, formatted and validated instantly.