Free Developer Tools

Convert YAML to JSON or JSON to YAML instantly. Correctly handles Docker Compose anchors, Kubernetes multi-document manifests, and GitHub Actions workflows. Free, no sign-up.

• Convert a docker-compose.yml to JSON for tooling
• Turn a Kubernetes manifest into a JSON array of resources
• Convert JSON config into clean, readable YAML

Paste a curl command — including Chrome "Copy as cURL" — and get equivalent JavaScript fetch, Axios, or Python requests code instantly. Handles headers, JSON, form data, file uploads, and auth. Free, no sign-up.

• Turn an API doc's curl example into working code
• Convert a browser request copied from DevTools
• Switch a curl call to async/await

Generate realistic fake JSON test data — names, emails, addresses, IDs, and more — with a custom schema builder and reproducible seeds. Export as JSON or NDJSON. Free, no sign-up.

• Stub API responses before the backend exists
• Seed a database or fixture for testing
• Populate a UI with realistic-looking data for design review

Calculate network address, broadcast address, usable host range, and subnet mask from any IP address and CIDR notation. Includes a subnet splitter and CIDR reference chart. Free, no sign-up.

• Find the usable host range for a /24, /27, etc.
• Convert between CIDR prefix and subnet mask
• Split a network into smaller equal subnets

Set a min and max size across two viewport widths and get a copy-paste-ready CSS clamp() value instantly, with a live curve preview. Works for font-size, padding, gap, and more. Free, no sign-up.

• Build fluid headings without breakpoints
• Scale spacing/padding across screen sizes
• Convert px sizing to accessible rem-based clamp()

Minify HTML to reduce file size or beautify it for readability — free, instant, zero-dependency, 100% browser-based. Remove comments, collapse whitespace, shorten booleans. Configurable indent style for beautification. See exact byte savings. No upload, no sign-up.

• Minify HTML before deploying to production
• Beautify auto-generated or CMS-exported HTML for debugging
• Strip comments and collapse whitespace to improve page load speed

Write Markdown and see the rendered HTML side-by-side in real time. Supports GitHub Flavored Markdown — tables, task lists, fenced code blocks with syntax highlighting — plus one-click HTML & .md export. 100% browser-based.

• Preview README.md files before committing
• Convert Markdown to HTML for a CMS
• Write docs with real-time rendering

Instantly generate bulk UUIDs (Universally Unique Identifiers) and GUIDs. Supports random (v4) and timestamp (v1) formats. 100% client-side data privacy.

• Generate database keys
• Create API testing tokens
• Mock massive datasets

Create stunning CSS gradients instantly. Live preview and generate code for linear, radial, and conic backgrounds. Copy-ready CSS, no upload needed.

• Design modern UI backgrounds
• Replace heavy background images
• Generate cross-browser CSS

Paste messy JSON, get clean, indented output instantly. Real-time error detection with precise line and column numbers. Minify for production or beautify for debugging.

• Debug malformed API responses
• Format config files
• Prepare JSON for production

The all-in-one data playground. Convert between all major formats, run JSONPath queries, view data as tree or table, fetch from URLs, and export charts.

• Transform API response to CSV
• Extract fields with JSONPath
• Migrate data between formats

Upload CSV or paste data and instantly build interactive bar, line, pie, and scatter charts. Filter, aggregate, customise colors, and download as PNG or PDF.

• Visualise sales or traffic data
• Build presentation charts
• Explore CSV datasets

Compute secure MD5, SHA-1, SHA-256, and SHA-512 checksums for text or files. 100% client-side privacy using the native Web Crypto API. Zero server uploads.

• Verify file integrity
• Hash API payloads
• Test password salting mechanisms

Instantly encode or decode full URLs and query strings. Safely parse percent-encoded links, encodeURI, and encodeURIComponent. 100% client-side data privacy.

• Format API requests safely
• Extract readable JSON from callback links
• Clean broken URLs

Paste any JWT to instantly decode the header, payload, and signature. Checks expiration, detects security pitfalls (like the "none" algorithm), and verifies HS256 signatures.

• Debug auth tokens from any API
• Validate JWT expiry (exp)
• Detect security vulnerabilities

Generate secure, random passwords with custom length (up to 128 chars), character sets (uppercase, lowercase, numbers, symbols), strength indicator, and copy to clipboard.

• Generate API keys and secrets
• Create server admin passwords
• Bulk password generation

Create cron schedules with a visual editor that translates every expression into plain English in real time. Parse existing cron strings, use presets, and generate full crontab commands.

• Schedule automated backups
• Set up recurring maintenance jobs
• Debug existing cron strings

Convert Unix timestamps to human-readable dates and back. Auto-detects seconds, milliseconds, microseconds, or nanoseconds. Batch mode, all IANA timezones, start/end of day ranges.

• Debug server log timestamps
• Work with API date fields
• Convert database time values

Select any combination of languages, frameworks, platforms, operating systems, and editors to instantly generate a correct, deduplicated .gitignore file based on GitHub's official templates. Free, no sign-up.

• Set up a new repo before your first commit
• Add missing rules to an existing project
• Combine Node + Python + macOS in one file

Compare API costs across 16 models from OpenAI, Anthropic, Google, Mistral, and DeepSeek. Enter your token volume and requests per day to see per-request, daily, monthly, and annual cost projections — ranked from cheapest to most expensive. Realistic usage presets included. Free, no sign-up.

• Choose the cheapest model for a chatbot
• Budget an AI feature before launch
• Compare GPT-4o vs Claude vs Gemini costs

Count tokens for GPT-5, GPT-4.1, GPT-4o, GPT-4, and GPT-3.5 using the real BPE tokenizer (the same encoding as OpenAI's tiktoken) — exact counts, not estimates. Color-coded visual token breakdown, estimated API cost calculator, and character-based estimates for Claude and Gemini. Free, no sign-up.

• Check prompt length before hitting context limits
• Estimate OpenAI/Claude/Gemini API costs
• Debug why a request exceeded the token limit

Create customizable QR codes for URLs, plain text, email addresses, phone numbers, SMS, and WiFi credentials. Custom colors, error correction, and multiple download formats.

• Add website link to printed materials
• Share WiFi credentials
• Create contactless business cards

Generate classic or themed placeholder text as paragraphs, sentences, words, or HTML lists. Multiple languages, custom themes, and export as plain text, HTML, JSON, or Markdown.

• Fill UI mockups and wireframes
• Test CMS content rendering
• Create design prototypes

Build neumorphic (Soft UI) designs with a live preview. Adjust size, radius, shadow distance, blur, and color. Generate the CSS code for extruded and pressed states with one click.

• Design soft UI cards and buttons
• Build modern dashboard components
• Learn neumorphism CSS