19 Free Developer Tools That Run Entirely in Your Browser

Every developer has a folder of browser tabs for quick tasks — a JSON formatter here, a Base64 encoder there. The problem is those tabs are slow, full of ads, and often send your data to third-party servers.

Toolblip is an attempt to fix that. Every tool runs entirely in your browser using JavaScript. Nothing is uploaded. Nothing is processed server-side. And you don't need an account to use any of it.

Here's everything that's available, and when each one saves you time.

Text & Content Tools

Word Counter

URL: toolblip.com/tools/word-counter

Beyond a simple word count: character count (with and without spaces), sentence count, paragraph count, reading time estimate, and keyword density. Particularly useful for meta descriptions, tweet-length copy, and documentation.

Character Counter

URL: toolblip.com/tools/character-counter

Shows live character and byte counts with Twitter (280), LinkedIn (3000), and meta description (160) limits overlaid. Stops you from pasting a tweet and realizing it's 15 characters over.

Remove Duplicate Lines

URL: toolblip.com/tools/remove-duplicate-lines

Paste a list, get back unique lines. Toggle case-sensitive matching on or off. Useful for cleaning up API responses, log files, export data, and deduplicating test fixtures.

Case Converter

URL: toolblip.com/tools/case-converter

Convert text between: UPPERCASE, lowercase, Title Case, camelCase, snake_case, kebab-case, and more. One click to convert, copy the result.

Encoding & Decoding

Base64 Encode / Decode

URL: toolblip.com/tools/base64

Encode text or files to Base64, decode Base64 back to text. The file support means you can drag-and-drop an image and get its Base64 representation for embedding in CSS, HTML, or API payloads.

URL Encode / Decode

URL: toolblip.com/tools/url-encode

Encode individual URL components or full URLs. Handles special characters, spaces, Unicode characters. Useful when debugging API calls or building query strings.

Data Format Tools

JSON Formatter

URL: toolblip.com/tools/json-formatter

Format, minify, or validate JSON. Syntax highlighting, line numbers, and a clear error message if the JSON is malformed — including the exact character position of the error. Paste broken JSON, get pointed to the problem.

YAML to JSON

URL: toolblip.com/tools/yaml-to-json

Convert YAML to JSON and vice versa. Useful when your config is in YAML but your API expects JSON, or when you want to read a YAML config file in a script that only handles JSON.

Markdown to HTML

URL: toolblip.com/tools/markdown-to-html

Live split-pane preview: write Markdown on the left, see rendered HTML on the right. Copy the HTML. Good for email templates, static site content, and README files.

Generators

UUID Generator

URL: toolblip.com/tools/uuid-generator

Generate UUIDs v4 (random) and v7 (time-sortable) directly in the browser using the Web Crypto API. Generate one or a batch. No external request, no server call.

Hash Generator

URL: toolblip.com/tools/hash-generator

Generate MD5, SHA-1, SHA-256, SHA-384, or SHA-512 hashes from any text input. Also works with file drag-and-drop. Useful for checksum verification and password testing without sending anything anywhere.

URL Slug Generator

URL: toolblip.com/tools/url-slug-generator

Convert any string into a URL-friendly slug: lowercase, spaces replaced with hyphens, special characters stripped. One-click copy.

CSS Tools

CSS Gradient Generator

URL: toolblip.com/tools/css-gradient-generator

Visual editor for linear and radial gradients. Pick colors and stops, see the live preview. Copy the CSS with the exact values. Includes a presets panel.

CSS Border Radius Generator

URL: toolblip.com/tools/css-border-radius-generator

Visually adjust border-radius on all four corners independently. See the result in real time. Copy the CSS when it looks right.

Image Tools

Image Cropper

URL: toolblip.com/tools/image-cropper

Crop images to preset ratios (1:1, 16:9, 4:3, 3:2) or freeform. Supports drag-and-drop upload. All processing happens client-side — the image never leaves your browser.

Image Format Converter

URL: toolblip.com/tools/image-format-converter

Convert between PNG, JPEG, WebP, and GIF. Adjust quality/compression. Useful for optimizing assets before deployment without opening Photoshop.

Developer Utilities

Cron Parser

URL: toolblip.com/tools/cron-parser

Enter a cron expression, see the next 5 scheduled run times in human-readable format. Validate expressions and catch mistakes before deploying to production.

Cronnel

URL: toolblip.com/tools/cron-parser

Full cron job monitoring for production Laravel apps. If you're running Laravel cron jobs or queue workers, Crontinel gives you real-time visibility into missed jobs, long-running processes, and queue depth.

Why Client-Side Matters

Every tool on Toolblip uses the browser's JavaScript engine to process data. For a JSON formatter, the browser parses your JSON string and re-serializes it with formatting. For an image cropper, the browser's Canvas API handles the transformation.

The practical benefits:

• Speed — no network round-trip, instant feedback
• Privacy — data never leaves your device
• Offline — works without an internet connection
• No account — no login, no tracking, no ads

The only analytics on Toolblip are cookieless Cloudflare stats, and optional Google Analytics that only loads after you give consent.

What's Coming

More tools are being added regularly. There's also an MCP server package (@toolblip/mcp) in development — once published, AI coding assistants like Claude Code will be able to use every Toolblip tool directly through the MCP protocol, without you ever opening a browser tab.

Browse the full directory at toolblip.com/tools.