Web Developer Utilities
Fast, client-side tools for formatting code, testing regex, and converting data formats.
Free developer tools for code formatting, encoding, hashing, and network analysis — all browser-based with no account required. Built for the daily workflow of working engineers.
Why Use Free Developer Tools?
- → Format, validate, and convert JSON, SQL, CSS, and other code formats instantly without installing CLI tools or IDE extensions.
- → Decode JWTs, generate UUIDs, and convert between data formats using tools that handle edge cases correctly.
- → Your code, API responses, and configuration data stay in your browser — nothing is sent to a server or logged.
How to choose the right tool
Start with the result you need, then choose the smallest tool that answers that question directly. If you are estimating, forecasting, or comparing options, use the calculator that matches the decision rather than a general spreadsheet. For example, a quick fee estimate belongs in a fee calculator, while a longer planning question belongs in a budgeting, ROI, or comparison tool. This keeps the inputs focused and makes the result easier to check.
What makes these tools private
The tools in this category are designed to run in your browser whenever possible. That means your numbers, text, files, or planning details stay on your device instead of being uploaded to an account dashboard. You can refresh the page, change the inputs, and compare scenarios without creating a login or storing personal work in our database.
A simple workflow
Use one tool for the first pass, copy the result you care about, then open a related tool if the decision needs more detail. Most people get the best answer by moving from a quick estimate to a more specific calculator, not by trying to force every question into one oversized form. Each page includes plain-language notes so you can understand the formula, common mistakes, and when the answer should be treated as an estimate instead of professional advice.
Before you rely on the result
Double-check the assumptions behind any calculator result before you use it for money, health, taxes, travel, legal, or work decisions. Small input changes can shift an estimate quickly, especially when rates, deadlines, file formats, or platform rules are involved. When a page includes a formula, source note, or last-updated date, use that context to decide whether the result is current enough for your situation.
If a result looks surprising, run the numbers again with simpler inputs and compare the answer against another trusted source before acting on it.
JSON Formatter
Validate and beautify JSON payloads.
Base64 Encoder
Encode and decode strings or files to Base64.
QR Code Gen
Generate customizable SVG/PNG QR codes.
Regex Tester
Test and debug regular expressions in real-time.
CSS Minifier
Minify and compile CSS styles.
LLM API Cost
Estimate token overhead for OpenAI, Claude, and Gemini.
String Formatter
Instantly convert text to camelCase, snake_case, PascalCase, or kebab-case.
JSON to CSV
Flatten and convert nested JSON objects into tabular CSV data.
Meta Tag Gen
Generate HTML meta tags, Twitter Cards, and Open Graph data.
UUID Generator
Instantly generate bulk v4 UUIDs / GUIDs.
JWT Decoder
Decode JSON Web Tokens securely without sending payloads.
HTML Entity Encoder
Safely encode and decode HTML entities to prevent XSS.
Markdown to HTML
Convert Markdown to clean HTML with live preview and XSS protection.
Text Diff Checker
Compare two text blocks or code snippets to find the exact differences.
Unix Timestamp
Convert Unix epoch times to human-readable dates and vice versa.
IP Subnet Calculator
Calculate network CIDR ranges, broadcast addresses, and usable hosts.
JSON to YAML
Instantly translate JSON configurations into clean, readable YAML.
URL Encoder/Decoder
Safely encode URLs for HTTP parameters or decode percent-encoded strings.
SQL Formatter
Instantly beautify messy SQL queries with perfect indentation.
Frequently Asked Questions
What developer tools are available?
JSON formatter, JSON to CSV, JSON to YAML, regex tester, CSS minifier, SQL formatter, string formatter, URL encoder, Base64 encoder, UUID generator, JWT decoder, Markdown to HTML, HTML entity encoder, Unix timestamp converter, bcrypt generator, network subnet calculator, diff checker, LLM API cost estimator, and meta tag generator.
Do these tools work with sensitive code?
Yes — every tool runs client-side in your browser. No code, queries, tokens, or IP addresses are ever sent to a server.
Are there usage limits?
No limits of any kind — no rate limiting, no character caps, no account required.
Can I use these tools offline?
Yes. After the page loads, all processing is local. You can disconnect from the internet and every tool continues to function.