devvkitdev

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A collection of free, fast, privacy-first developer tools. No login, no tracking, no bloat. Just clean tools that do one thing well.

Categories

All Tools

ai

Prompt Library

Browse 500+ AI prompts for coding, writing, analysis, and more.

ai

Dataset Browser

Search 400K+ public AI/ML datasets from Hugging Face, Kaggle, and more.

ai

LLM Token Counter

Count tokens in text for GPT-4, Claude, Llama, and other models.

ai

System Prompt Builder

Build, test, and refine system prompts for LLM-based applications.

ai

Model Card Generator

Generate standardized model cards for ML models with documentation.

dev

JSON Formatter

Format, validate, minify, and prettify JSON data instantly.

dev

JWT Decoder

Decode and inspect JWT tokens — header, payload, signature, expiration.

dev

Base64 Encoder/Decoder

Encode text or files to Base64 and decode back. UTF-8 safe.

dev

Regex Tester

Test regular expressions in real-time with match highlighting and groups.

dev

UUID Generator

Generate UUIDs and ULIDs — v4, v7, bulk mode, copy, download.

dev

Timestamp Converter

Convert Unix timestamps to human-readable dates and back.

dev

Hash Generator

Generate MD5, SHA-1, SHA-256, SHA-512 hashes for text and files.

dev

SQL Formatter

Format and beautify SQL queries for PostgreSQL, MySQL, SQLite.

dev

Cron Expression Generator

Build and test cron expressions with visual schedule previews.

dev

.gitignore Generator

Generate .gitignore files with 500+ templates for any tech stack.

converters

JSON to CSV Converter

Convert JSON arrays to CSV spreadsheets and back. Supports nested data.

converters

JSON to YAML Converter

Convert between JSON and YAML formats with comments preserved.

converters

Markdown to HTML Converter

Convert Markdown to clean HTML with live preview and GFM support.

converters

Color Converter

Convert colors between HEX, RGB, HSL, HSV, and CMYK formats.

calculators

LLM Token Cost Calculator

Calculate API costs for GPT-4, Claude, Gemini, and other LLMs.

calculators

API Rate Limit Calculator

Calculate rate limits, burst capacity, and throttling for APIs.

calculators

Database Size Estimator

Estimate database size based on row count, columns, and data types.

calculators

Bandwidth Cost Calculator

Calculate bandwidth and data transfer costs across cloud providers.

generators

Dummy Data Generator

Generate realistic fake data in JSON, CSV, or SQL format.

generators

TypeScript Interface Generator

Convert JSON to TypeScript interfaces, types, and Zod schemas.

generators

SQL Schema Generator

Generate CREATE TABLE statements from JSON or CSV data.

generators

OpenAPI Spec Generator

Generate OpenAPI 3.1 specifications from sample data.

generators

Mock API Response Generator

Generate realistic mock API responses for frontend development.

Why devvkit?

No login, no tracking

Everything runs in your browser. We never store your data.

Fast by default

Server-rendered, optimized, minimal JavaScript. Tools load instantly.

Free forever

Every tool is free. No plans, no trials, no upsells.