40+ Free Developer Tools: No Signup Required

Every developer knows the frustration. You need to quickly format some JSON, generate a UUID, or check color contrast ratios. So you search online, find a tool, and then hit a signup wall. Or worse, you land on a page drowning in ads that makes the tool nearly unusable.

We built something different.

High Mountain Studio offers a growing collection of free, browser-based tools designed for developers, designers, and marketers. No account required. No email harvesting. No intrusive advertisements. Just clean, functional utilities that work.

This guide walks through every tool we offer, organized by category, with practical examples of when you might reach for each one.

Why We Built These Tools

Before diving into the tools themselves, a bit of context. We build web applications for clients. During that work, we constantly reach for small utilities: formatting data, generating placeholder content, checking accessibility compliance, creating meta tags.

Rather than rely on scattered third-party tools of varying quality, we built our own. And since these tools cost nothing to run (they execute entirely in your browser), we decided to make them available to everyone.

Every tool runs client-side. Your data never touches our servers. Paste in sensitive JSON or API keys without worry.

Text Tools

Text manipulation is one of the most common developer tasks. Whether you're preparing content for a CMS, cleaning up data exports, or generating placeholder text, these tools handle the tedious work.

Word Counter

Count words, characters, sentences, and paragraphs in any text. The tool provides real-time statistics as you type or paste content.

When to use it:

• Checking content length against character limits (meta descriptions, tweets, ad copy)
• Estimating read time for blog posts
• Analyzing text density for SEO purposes
• Meeting word count requirements for assignments or contracts

The tool breaks down character counts with and without spaces, which matters when platforms count differently.

Case Converter

Transform text between different case formats with a single click. Supports uppercase, lowercase, title case, sentence case, camelCase, PascalCase, snake_case, kebab-case, and more.

When to use it:

• Converting headings to title case for consistent styling
• Transforming variable names between naming conventions
• Fixing text that was accidentally typed in caps lock
• Preparing data for systems with specific case requirements

Developers switching between languages with different naming conventions (JavaScript's camelCase vs Python's snake_case) will find this particularly useful.

Lorem Ipsum Generator

Generate placeholder text for designs and layouts. Control the output format: paragraphs, sentences, or words. Choose between classic Lorem Ipsum or alternative placeholder text styles.

When to use it:

• Filling design mockups with realistic text blocks
• Testing how layouts handle varying content lengths
• Populating database fields during development
• Creating content placeholders for client presentations

Slug Generator

Convert any text into URL-friendly slugs. Handles special characters, accents, spaces, and punctuation automatically.

When to use it:

• Creating SEO-friendly URLs for blog posts
• Generating file names from titles
• Building permalink structures for CMS content
• Preparing data for API endpoints that require slugs

The tool shows a preview of how the slug will appear in a full URL, helping you catch overly long or awkward slugs before implementation.

Text Diff

Compare two blocks of text and highlight the differences. See additions, deletions, and modifications at a glance.

When to use it:

• Comparing code versions when git diff is not available
• Reviewing content changes before publishing
• Checking configuration file modifications
• Verifying that find-and-replace operations worked correctly

The diff view uses color coding to make changes immediately obvious: green for additions, red for deletions.

Developer Tools

The core utilities that developers reach for daily. Encoding, decoding, formatting, converting, and validating data in various formats.

JSON Formatter

Format, validate, and minify JSON data. The tool parses your input and presents it with proper indentation, syntax highlighting, and collapsible sections for nested objects.

When to use it:

• Making API responses readable for debugging
• Validating JSON structure before sending to an endpoint
• Minifying JSON to reduce payload size
• Extracting specific values from complex nested structures

Invalid JSON triggers clear error messages pointing to the exact line and character where parsing failed.

JSON to TypeScript

Generate TypeScript interfaces from JSON data. Paste in a JSON object or array, and the tool infers types and outputs ready-to-use TypeScript definitions.

When to use it:

• Creating type definitions for API responses
• Bootstrapping TypeScript projects from existing JSON data
• Documenting data structures with type annotations
• Converting JavaScript objects to typed interfaces

The tool handles nested objects, arrays, optional fields, and union types intelligently.

Base64 Encoder/Decoder

Encode text or files to Base64, or decode Base64 strings back to their original form. Supports both standard and URL-safe Base64 variants.

When to use it:

• Encoding images for inline CSS or HTML
• Preparing data for APIs that require Base64 encoding
• Decoding Base64 strings found in configurations or tokens
• Creating data URIs for small assets

URL Encoder/Decoder

Encode special characters for safe URL transmission, or decode percent-encoded strings back to readable text.

When to use it:

• Preparing query parameters with special characters
• Debugging URL encoding issues in web applications
• Creating properly encoded redirect URLs
• Decoding URLs copied from browser address bars

HTML Entities Encoder/Decoder

Convert special characters to HTML entities and vice versa. Handles named entities (like &) and numeric entities (like &).

When to use it:

• Escaping user input for safe HTML display
• Preparing content for XML or HTML documents
• Debugging character encoding issues
• Converting special characters in database content

Regex Tester

Test regular expressions against sample text with real-time match highlighting. See capture groups, test global vs single matches, and explore common regex patterns.

When to use it:

• Building and debugging regular expressions
• Testing patterns before implementing in code
• Learning regex syntax with immediate visual feedback
• Validating that patterns match (and do not match) expected inputs

The tool explains what each part of your regex does, making it educational as well as functional.

Timestamp Converter

Convert between Unix timestamps (seconds and milliseconds) and human-readable dates. Supports multiple date formats and timezones.

When to use it:

• Debugging timestamp-related bugs in applications
• Converting log file timestamps to readable dates
• Preparing date data for APIs that expect Unix timestamps
• Checking when events occurred based on epoch values

CSS Unit Converter

Convert between CSS units: pixels, rem, em, percentages, viewport units, and more. Set a base font size and see equivalent values across all units.

When to use it:

• Converting designs from pixel-based to relative units
• Calculating rem values for responsive typography
• Translating viewport-based sizing requirements
• Ensuring consistent spacing across different unit systems

Markdown Preview

Write Markdown and see the rendered HTML output in real-time. Supports GitHub Flavored Markdown, including tables, task lists, and syntax-highlighted code blocks.

When to use it:

• Drafting README files before committing
• Writing documentation with live preview
• Testing Markdown syntax for blog platforms
• Converting Markdown to HTML for other uses

JWT Decoder

Decode JSON Web Tokens to inspect their header, payload, and signature. The tool does not verify signatures (which requires the secret key) but lets you examine token contents.

When to use it:

• Debugging authentication issues
• Checking token expiration times
• Inspecting claims and permissions in JWTs
• Understanding the structure of tokens from third-party services

A reminder: never paste production tokens containing sensitive data into online tools. This tool runs entirely in your browser, but caution with credentials is always warranted.

Cron Expression Generator

Build cron expressions visually instead of memorizing the syntax. Select intervals, specific times, days of the week, and see the resulting cron string with a human-readable explanation.

When to use it:

• Scheduling background jobs and automated tasks
• Setting up CI/CD pipeline schedules
• Configuring server maintenance windows
• Creating time-based triggers for webhooks

.gitignore Generator

Generate .gitignore files for any technology stack. Select your languages, frameworks, IDEs, and operating systems, then download a comprehensive ignore file.

When to use it:

• Starting new projects with proper ignore patterns
• Adding support for new technologies to existing repos
• Ensuring sensitive files are not accidentally committed
• Standardizing ignore patterns across team projects

The tool pulls from common patterns and best practices for each technology.

Code Screenshot Generator

Create beautiful images of code snippets for sharing on social media, documentation, or presentations. Customize themes, fonts, backgrounds, and padding.

When to use it:

• Sharing code snippets on Twitter or LinkedIn
• Creating visuals for blog posts and tutorials
• Building slide decks with syntax-highlighted code
• Documenting code examples in a visually appealing format

SEO Tools

Search engine optimization requires proper metadata, structured URLs, and technical compliance. These tools help you get the details right.

Meta Tag Generator

Generate complete meta tags for SEO, Open Graph (Facebook), and Twitter Cards. Fill in your content details and get copy-paste-ready HTML.

When to use it:

• Adding meta tags to new pages or blog posts
• Ensuring consistent metadata across a site
• Preparing social sharing tags for marketing campaigns
• Auditing and updating existing meta implementations

The tool validates character lengths and warns when titles or descriptions exceed recommended limits.

Open Graph Preview

Preview how your page will appear when shared on social platforms. Enter a URL and see the Open Graph title, description, and image that Facebook, Twitter, LinkedIn, and other platforms will display.

When to use it:

• Testing social sharing appearance before publishing
• Debugging why shared links look wrong
• Verifying Open Graph image dimensions and quality
• Comparing how different platforms render your metadata

Robots.txt Generator

Create robots.txt files that tell search engine crawlers which pages to index and which to ignore. Select common presets or build custom rules.

When to use it:

• Setting up crawler rules for new websites
• Blocking staging environments from search indexes
• Protecting private or duplicate content from indexing
• Configuring crawl delays for resource management

Sitemap Generator

Build XML sitemaps by entering your site's URLs. Set priorities, change frequencies, and last-modified dates for each page.

When to use it:

• Creating initial sitemaps for new sites
• Building sitemaps for static site generators
• Testing sitemap structure before automating generation
• Submitting specific pages to search engines

Keyword Density Analyzer

Analyze text content to see which words and phrases appear most frequently. Useful for understanding content focus and avoiding keyword stuffing.

When to use it:

• Auditing content for SEO keyword usage
• Identifying overused words in writing
• Analyzing competitor content strategies
• Ensuring natural keyword distribution

Heading Structure Analyzer

Check the heading hierarchy (H1, H2, H3, etc.) of any webpage. Proper heading structure improves both SEO and accessibility.

When to use it:

• Auditing page structure for SEO compliance
• Ensuring accessibility standards are met
• Reviewing content organization before publishing
• Checking that pages have exactly one H1 tag

Design Tools

Color, layout, and visual utilities for designers and developers working on user interfaces.

Color Contrast Checker

Test color combinations against WCAG accessibility guidelines. See whether your text and background colors meet AA or AAA compliance levels.

When to use it:

• Ensuring readable text for all users
• Meeting accessibility requirements for clients
• Testing color schemes during design phases
• Auditing existing designs for compliance issues

The tool shows exact contrast ratios and explains what each compliance level requires.

Color Palette Generator

Generate harmonious color schemes from a base color. Create complementary, analogous, triadic, and other color relationships.

When to use it:

• Starting new design projects with cohesive colors
• Expanding brand colors into full palettes
• Finding colors that work well together
• Exploring color theory relationships

Gradient Generator

Build CSS gradients visually. Choose colors, adjust angles and positions, and copy the generated CSS code.

When to use it:

• Creating background gradients for sections or buttons
• Building complex multi-stop gradients
• Converting design tool gradients to CSS
• Experimenting with gradient directions and types

Supports linear, radial, and conic gradients with multiple color stops.

Image Resizer

Resize images to specific dimensions directly in your browser. Maintain aspect ratio or set custom proportions. Download the result without uploading to any server.

When to use it:

• Preparing images for social media platforms
• Resizing screenshots for documentation
• Creating thumbnails from larger images
• Adjusting image dimensions for web optimization

Favicon Generator

Generate favicons in all required sizes from a single source image. Get ICO files, Apple touch icons, and Android icons in one download.

When to use it:

• Creating favicons for new websites
• Updating outdated or missing favicon formats
• Generating all required sizes from a logo
• Ensuring cross-browser and cross-device favicon support

Box Shadow Generator

Design CSS box shadows with visual controls. Adjust offset, blur, spread, color, and opacity. Stack multiple shadows for complex effects.

When to use it:

• Creating elevation effects for cards and modals
• Building consistent shadow systems for design systems
• Experimenting with shadow aesthetics
• Generating complex layered shadow effects

Flexbox and Grid Playground

Learn and experiment with CSS Flexbox and Grid layouts visually. Adjust properties and see how they affect element positioning in real-time.

When to use it:

• Learning Flexbox and Grid concepts
• Debugging layout issues by testing configurations
• Building layouts visually before writing code
• Teaching CSS layout techniques to others

Generators

Utilities that create data, codes, and content for various development and business needs.

Password Generator

Generate secure, random passwords. Control length, character types (uppercase, lowercase, numbers, symbols), and avoid ambiguous characters.

When to use it:

• Creating strong passwords for new accounts
• Generating API keys and secret tokens
• Building password suggestions into applications
• Creating temporary passwords for user onboarding

UUID Generator

Generate universally unique identifiers (UUIDs) in various versions. Copy individual UUIDs or generate them in bulk.

When to use it:

• Creating unique identifiers for database records
• Generating correlation IDs for logging
• Building unique keys for distributed systems
• Testing systems that require UUID inputs

QR Code Generator

Create QR codes from text, URLs, contact information, or WiFi credentials. Customize colors and download in various formats.

When to use it:

• Linking physical materials to digital content
• Creating WiFi access codes for guests
• Building QR codes for business cards or menus
• Generating scannable links for marketing materials

Hash Generator

Generate cryptographic hashes (MD5, SHA-1, SHA-256, SHA-512) from text input. Useful for checksums and data integrity verification.

When to use it:

• Creating checksums for file verification
• Hashing passwords for comparison (use proper libraries in production)
• Generating unique identifiers from content
• Verifying data integrity across transfers

Email Signature Generator

Build professional HTML email signatures. Add your name, title, company, contact information, and social links. Copy the HTML for use in any email client.

When to use it:

• Creating consistent signatures for team members
• Building branded email signatures
• Updating contact information across signatures
• Designing signatures that render properly in all clients

Placeholder Image Generator

Generate placeholder images in any dimensions. Choose solid colors, gradients, or category-based stock imagery for mockups.

When to use it:

• Creating mockups before final images are ready
• Testing responsive image behavior
• Filling content slots during development
• Building prototypes with realistic image placeholders

Aspect Ratio Calculator

Calculate dimensions while maintaining aspect ratios. Enter width or height and the tool computes the other dimension based on your chosen ratio.

When to use it:

• Resizing images without distortion
• Planning video dimensions for different platforms
• Calculating responsive container sizes
• Converting between different aspect ratio standards

Using These Tools in Your Workflow

The tools work best when integrated into your regular development workflow rather than visited occasionally when you remember they exist.

Bookmark the tools page. Quick access matters when you need to format JSON during a debugging session or check a color contrast ratio during a design review.

Use keyboard shortcuts. Most tools support common shortcuts like Ctrl+V to paste, Ctrl+C to copy results, and Ctrl+Enter to process input.

Chain tools together. Generate a slug from your blog title, then use that slug in the meta tag generator. Create a color palette, then check each combination in the contrast checker.

Share links with your team. The tools page makes a useful resource for onboarding new developers or standardizing team utilities.

Coming Soon

We continue adding new tools based on what we need in our own work and what users request. Current additions in development include:

• SVG optimizer
• JSON schema generator
• CSS minifier
• JavaScript minifier
• HTTP header analyzer
• DNS lookup tool

Have a tool you would find useful? Let us know.

Build With Confidence

These tools represent a small part of what we do at High Mountain Studio. We build web applications, SaaS platforms, and digital products for businesses that need software to perform.

If you need more than a utility (if you need a complete web application built with the same attention to detail we put into these free tools), schedule a consultation to discuss your project.

All tools are available at highmountainstudio.com/tools.