Free Online Developer Tools & Client-Side Utilities
Free browser-based utilities for web developers. Instantly format, validate, convert, encode, and inspect data locally without ever sending it to a server.
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Developer Tools
Free Token Counter for LLMs
Estimate token usage for major LLM families so you can plan context size and API cost before sending a request.
Free JSON Schema Generator
Generate JSON Schema from sample payloads for API validation, AI tools, and typed interfaces.
cURL to Code Converter
Convert cURL commands into Python, JavaScript, Go, or PHP code for faster integration work.
API Key Generator
Generate random API keys locally in several common formats for development, testing, and internal tooling.
Webhook Tester
Format webhook payloads, verify HMAC signatures, and build cURL requests for local integration testing.
Function Calling Definition
Generate OpenAI-style function calling JSON from a sample payload or parameter schema.
Prompt Template
Build reusable prompt templates with variable placeholders and a live rendered preview.
Markdown to API Doc
Convert rough Markdown notes into structured API documentation HTML and a previewable outline.
Base64 Image to Data URI
Convert Base64 image data into a complete Data URI for multimodal prompts and inline previews.
JSON to TypeScript
Generate TypeScript interfaces and types from sample JSON for faster frontend and SDK work.
Latest from the Blog
Tutorials and best practices for modern developers.