Toolliyo Tools

Free Developer Tools

67 tools for JSON, HTML, CSS, PDF, images, fake data, security, and SEO — categorized, searchable, and SEO-friendly. All run in your browser.

JSON & Data (11) HTML & CSS (10) Fake & Mock Data (7) PDF Tools (3) Image Tools (6) Security & Encoding (9) Text & Code (11) Design & UI (6) SEO & Web (4) Calculators (0)

New developer tools

JSON Minifier NEW

Compress JSON to a single line for APIs.

JSON Path Extractor NEW

Extract nested values with dot notation paths.

OpenAPI / Swagger Viewer NEW

Explore API endpoints from OpenAPI 3 JSON specs.

JSON to CSV NEW

Convert JSON arrays to CSV for Excel and spreadsheets.

CSV to JSON NEW

Parse CSV text into JSON objects.

YAML ↔ JSON NEW

Convert between YAML and JSON for configs and CI.

CSS Beautifier NEW

Format and indent CSS code.

PX to REM Converter NEW

Convert px, rem, and em values for responsive CSS.

HTML to Markdown NEW

Convert HTML snippets to Markdown text.

Fake Name Generator NEW

Random first and last names for test data.

Fake User Generator NEW

Full user profiles with email, phone, and address JSON.

Fake Email Generator NEW

Disposable-style emails for signup testing.

Fake Phone Generator NEW

International phone numbers for forms and APIs.

PDF Merger NEW

Combine multiple PDF files into one — in your browser.

Images to PDF NEW

Convert JPG/PNG images into a single PDF document.

JWT Encoder NEW

Build HS256 JWTs for API testing.

UUID Generator NEW

Generate v4 UUIDs in bulk.

URL Parser NEW

Break down URLs into protocol, host, path, and query.

.ENV Parser NEW

Parse .env files to JSON for debugging configs.

Markdown Preview NEW

Live Markdown to HTML preview.

SQL Formatter NEW

Beautify SQL queries with keyword casing.

XML Formatter NEW

Pretty-print and indent XML documents.

Cron Expression Generator NEW

Build cron schedules with human-readable descriptions.

API Request Tester NEW

Send GET/POST requests and inspect JSON responses.

Case Converter NEW

camelCase, snake_case, kebab-case, and Title Case.

URL Slug Generator NEW

Convert titles to SEO-friendly URL slugs.

.gitignore Generator NEW

Generate .gitignore from stack presets (Node, .NET, Python).

WCAG Contrast Checker NEW

Check foreground/background contrast ratios for accessibility.

All tools (67)

JSON Formatter

Beautify and pretty-print JSON with syntax highlighting.

JSON Validator

Validate JSON and highlight parse errors.

JSON Minifier NEW

Compress JSON to a single line for APIs.

JSON Path Extractor NEW

Extract nested values with dot notation paths.

OpenAPI / Swagger Viewer NEW

Explore API endpoints from OpenAPI 3 JSON specs.

JSON to CSV NEW

Convert JSON arrays to CSV for Excel and spreadsheets.

CSV to JSON NEW

Parse CSV text into JSON objects.

YAML ↔ JSON NEW

Convert between YAML and JSON for configs and CI.

JSON Editor

Edit JSON trees with live preview.

Mock Data Generator

Generate test rows and export CSV, JSON, SQL.

JSON to HTML Table

Render JSON as an HTML table.

HTML Formatter

Beautify and indent HTML markup.

HTML Minifier

Minify HTML for faster page loads.

HTML Entity Converter

Encode and decode HTML entities.

HTML Escape

Escape special characters for safe HTML output.

CSS Minifier

Minify CSS stylesheets.

CSS Beautifier NEW

Format and indent CSS code.

PX to REM Converter NEW

Convert px, rem, and em values for responsive CSS.

HTML to Markdown NEW

Convert HTML snippets to Markdown text.

HTML Table Generator

Build HTML tables visually.

Word to HTML

Convert rich text to clean HTML.

Fake Name Generator NEW

Random first and last names for test data.

Fake User Generator NEW

Full user profiles with email, phone, and address JSON.

Fake Email Generator NEW

Disposable-style emails for signup testing.

Fake Phone Generator NEW

International phone numbers for forms and APIs.

Fake Address Generator

Random street addresses worldwide.

Fake Credit Card

Test card numbers for payment gateway sandboxes.

Lorem Ipsum Generator

Placeholder paragraphs for UI mockups.

All PDF Tools

Browse merge, split, and convert PDF utilities.

PDF Merger NEW

Combine multiple PDF files into one — in your browser.

Images to PDF NEW

Convert JPG/PNG images into a single PDF document.

Image to Base64

Encode images as Base64 data URIs.

Image Compressor

Reduce image file size online.

Image to WebP

Convert JPG/PNG to WebP format.

Image Resizer

Resize images to exact dimensions.

Remove Background

AI background removal for product photos.

GIF Maker

Create animated GIFs from images.

Base64 Encoder

Encode and decode Base64 strings.

Hash Generator

SHA-256, SHA-1, and MD5 hashes.

JWT Decoder

Decode JSON Web Token headers and payloads.

JWT Encoder NEW

Build HS256 JWTs for API testing.

UUID Generator NEW

Generate v4 UUIDs in bulk.

Password Generator

Strong random passwords.

URL Encoder

Encode and decode URL components.

URL Parser NEW

Break down URLs into protocol, host, path, and query.

.ENV Parser NEW

Parse .env files to JSON for debugging configs.

Regex Tester

Test regular expressions with match highlights.

Code Diff Viewer

Compare two code snippets side by side.

Markdown Preview NEW

Live Markdown to HTML preview.

SQL Formatter NEW

Beautify SQL queries with keyword casing.

XML Formatter NEW

Pretty-print and indent XML documents.

Cron Expression Generator NEW

Build cron schedules with human-readable descriptions.

API Request Tester NEW

Send GET/POST requests and inspect JSON responses.

Case Converter NEW

camelCase, snake_case, kebab-case, and Title Case.

URL Slug Generator NEW

Convert titles to SEO-friendly URL slugs.

.gitignore Generator NEW

Generate .gitignore from stack presets (Node, .NET, Python).

Unix Timestamp Converter

Convert epoch seconds to dates and back.

CSS Gradient Generator

Linear and radial CSS gradients.

Box Shadow Generator

CSS box-shadow visual editor.

Flexbox Generator

Visual CSS flexbox layout builder.

CSS Grid Generator

CSS grid template builder.

Color Palette Generator

Harmonious color palettes for UI.

WCAG Contrast Checker NEW

Check foreground/background contrast ratios for accessibility.

Meta Tags Generator

Open Graph and Twitter card meta tags.

XML Sitemap Generator

Build XML sitemaps for search engines.

Robots.txt Generator

Create robots.txt crawl rules.

Schema Markup Generator

JSON-LD structured data for rich results.

Frequently asked questions

Are these developer tools free?

Yes — every tool on Toolliyo is free to use in your browser with no account required.

Is my data sent to a server?

Most tools (JSON, fake data, formatters) run entirely client-side. Your input stays in your browser.

What tools do developers use most?

JSON formatters, CSV converters, fake user generators, UUID generators, JWT decoders, CSS/HTML minifiers, and Markdown previews are among the most popular.

Toolliyo Assistant

Ask about tutorials, ebooks, training, pricing, mentor services, and support. I use public site content only—not admin or internal tools.

care@toolliyo.com