Free Online Developer Tools
A growing collection of browser utilities and public API endpoints for AI agents. Use the web tools directly, or call JSON, Base64, and JWT endpoints from scripts and OpenAPI clients.
Developer Utilities
Generate AI-ready PRDs, estimate OpenAI, Claude, Gemini, and general LLM costs, plan AI SaaS pricing, build MCP stacks, generate MCP configs and env templates, format JSON, validate syntax, encode Base64, decode JWTs, encode URLs, generate UUID v4 values, format HTML and SQL, and preview Markdown without sending data to a server.
AI PRD Generator
Turn a product idea into a structured product requirements document for SaaS, AI agents, MCP servers, marketplaces, CRM tools, Chrome extensions, and mobile apps.
JSON Formatter
Free online JSON formatter, validator, and beautifier. Format, minify, validate, and copy JSON with syntax highlighting. No signup required.
JSON Validator
Free online JSON validator. Validate JSON syntax, find parsing errors, and verify JSON structure instantly.
Base64 Encoder Decoder
Encode and decode Base64 strings instantly with this free online Base64 converter.
JWT Decoder
Decode JWT tokens online. View headers, payloads, expiration times, and claims instantly.
URL Encoder Decoder
Encode and decode URLs instantly with this free online URL encoding tool.
UUID Generator
Generate secure UUID v4 identifiers instantly. Copy or download UUIDs for development use.
HTML Formatter
Free online HTML formatter. Beautify HTML markup, fix readable indentation, and copy formatted HTML instantly in your browser.
SQL Formatter
Free online SQL formatter. Beautify SELECT queries, clauses, joins, and conditions into readable SQL for debugging and review.
Markdown Previewer
Free online Markdown previewer. Write Markdown and preview headings, links, lists, code blocks, blockquotes, and formatted text instantly.
AI Cost Calculator
Free AI cost calculator for developers. Estimate GPT-5.5, Claude Sonnet, Gemini 2.5 Pro, DeepSeek, and Kimi API costs by input tokens, output tokens, and daily requests. Calculate daily, monthly, and yearly spend instantly.
OpenAI Cost Calculator
Estimate OpenAI API costs for GPT models using input tokens, output tokens, and daily requests. Calculate daily, monthly, and yearly AI spend.
Claude Cost Calculator
Estimate Claude API costs for Anthropic models using token usage and request volume. Compare Claude Sonnet and Opus monthly AI costs.
Gemini Cost Calculator
Estimate Google Gemini API costs from input tokens, output tokens, and request volume. Calculate monthly AI spend for Gemini apps.
AI SaaS Pricing Calculator
Calculate AI SaaS pricing from model costs, user usage, requests, and target gross margin. Estimate Pro plan pricing and break-even usage.
MCP Stack Builder
Build a recommended MCP server stack for Claude, Cursor, and AI agents. Choose your workflow, data sources, and security level.
Claude Desktop MCP Config Generator
Generate a browser-only claude_desktop_config.json MCP template for local servers, args, and env variable names. No login, upload, or real secrets.
Cursor MCP Config Generator
Create a browser-only Cursor MCP config template for coding agents, repo workflows, GitHub, filesystem, and docs servers. No login or upload.
MCP Server Config Generator
Generate safe MCP server JSON config templates for Claude, Cursor, filesystem, GitHub, browser, database, docs, and custom servers. Browser-only.
MCP Env Template Generator
Generate a safe .env.example template for MCP servers with placeholder API tokens, database URLs, and secret handling notes. No real secrets needed.
MCP Security Checklist Generator
Create a Markdown MCP security checklist for permissions, secrets, prompt injection, logging, approvals, and deployment readiness. Browser-only.
Veo Prompt Generator
Generate optimized Google Veo prompts for cinematic videos, ads, short films, and social content. Free online Veo prompt generator.
Prompt Injection Checker
Free prompt injection checker. Scan system prompts, agent prompts, and user inputs for injection attacks, secret leakage, and jailbreak risks.
Tool API for AI Agents
Call JSON, Base64, and JWT utilities through public HTTP endpoints and OpenAPI docs.