Free Developer Utilities & Tools

PAYLOAD: { "sub": "usr_48e" }

JWT inspector

JWT inspector. Use this privacy-first jwt inspector directly in your browser.

HEAD: { "alg": "HS256" }

Dockerfile linter

Lint your Dockerfile for common mistakes and best-practice violations. Detects missing WORKDIR, untagged base images, absent EXPOSE instructions, and more.

✓ Non-root USER configured

✓ Clean apt-get cache in RUN

✓ Multi-stage build target

DEVOPS Open ↗

DevOps

"At minute 0 past every 6th hour"

Cron explainer

Cron explainer. Use this privacy-first cron explainer directly in your browser.

0 */6 * * *

DEVOPS Open ↗

DevOps

Env diff

Env diff. Use this privacy-first env diff directly in your browser.

DEVOPS Open ↗

Git

Changelog formatter

Changelog formatter. Use this privacy-first changelog formatter directly in your browser.

GIT Open ↗

Compound interest

Compound interest. Use this privacy-first compound interest directly in your browser.

Calculators

Average calculator

Average calculator. Use this privacy-first average calculator directly in your browser.

CALCULATORS Open ↗

Date & Time

Date difference

Date difference. Use this privacy-first date difference directly in your browser.

DATE & TIME Open ↗

Performance

CLS checklist

CLS checklist. Use this privacy-first cls checklist directly in your browser.

PERFORMANCE Open ↗

Productivity

Checklist builder

Checklist builder. Use this privacy-first checklist builder directly in your browser.

PRODUCTIVITY Open ↗

Text

Reading time calculator

Reading time calculator. Use this privacy-first reading time calculator directly in your browser.

TEXT Open ↗

Education

Citation formatter

Citation formatter. Use this privacy-first citation formatter directly in your browser.

EDUCATION Open ↗

Data Analysis

Column profiler

Column profiler. Use this privacy-first column profiler directly in your browser.

DATA ANALYSIS Open ↗

Visualization

Color scale generator

Generate a Tailwind-style color palette from any hex color. Enter a base hex value and get a full 10-step shade scale from 50 to 900. Runs in your browser.

VISUALIZATION Open ↗

API

cURL builder

Build a complete cURL command from a human-readable request spec. Paste method, URL, headers, and body — get a ready-to-run curl command. Fully local.

API Open ↗

16 9 Dimensions Calculator

Browser native 16 9 Dimensions Calculator utility.

9 16 Dimensions Calculator

Browser native 9 16 Dimensions Calculator utility.

1920 × 1080 (YouTube / 1080p FHD)

Aspect Ratio Calculator

Browser native Aspect Ratio Calculator utility.

16 : 9

Background: #0A0A0A Foreground: #FAFAFA

Color Contrast Checker

Browser native Color Contrast Checker utility.

Text Contrast 18.5:1 AAA

Css Clamp Calculator

Browser native Css Clamp Calculator utility.

Fluid Font Size


clamp(1rem, 2.5vw, 2.5rem)

CSV

Csv To Json

Browser native Csv To Json utility.

CSV Open ↗

Dpi Print Size Calculator

Browser native Dpi Print Size Calculator utility.

Json Formatter

Browser native Json Formatter utility.

Json Minifier

Browser native Json Minifier utility.

Json To Typescript

Browser native Json To Typescript utility.

Json To Xml

Browser native Json To Xml utility.

Json Validator

Browser native Json Validator utility.

Megapixels To Resolution Calculator

Browser native Megapixels To Resolution Calculator utility.

Meta Tag Analyzer

Browser native Meta Tag Analyzer utility.

Opportunity Radar

Browser native Opportunity Radar utility.

Calculators

Percentage Difference Calculator

Browser native Percentage Difference Calculator utility.

CALCULATORS Open ↗

Pixels To Megapixels Calculator

Browser native Pixels To Megapixels Calculator utility.

Ppi Calculator

Browser native Ppi Calculator utility.

Profit Margin Calculator

Browser native Profit Margin Calculator utility.

Px To Rem

Browser native Px To Rem utility.

Resize Dimensions Calculator

Browser native Resize Dimensions Calculator utility.

Schema Generator

Browser native Schema Generator utility.

Sitemap Validator

Browser native Sitemap Validator utility.

Social Media

Social Media Image Sizes

Browser native Social Media Image Sizes utility.

SOCIAL-MEDIA Open ↗

Svg To Jsx

Browser native Svg To Jsx utility.

XML

Xml Formatter

Browser native Xml Formatter utility.

XML Open ↗

Yaml To Json

Browser native Yaml To Json utility.

YouTube

Youtube Video Size Calculator

Browser native Youtube Video Size Calculator utility.

YOUTUBE Open ↗

AI Prompt Optimizer

Optimize AI system prompts with explicit roles, context variables, and structured output rules.

Multi-Persona AI Prompt Generator

Generate structured system prompts across software engineering, SEO, and product management personas.

AI Text Perplexity & Burstiness Checker

Audit text for AI generation patterns using sentence burstiness metrics and vocabulary perplexity proxies.

LLM BPE Tokenizer & Multi-Model Counter

Count tokens across GPT-4o, Claude 3.5 Sonnet, and Llama 3 models.

Multi-Model BPE Tokens

RAG Retrieval Precision & Recall Evaluator

Audit RAG retrieval quality: calculate Precision@K, Recall@K, F1 Score, and Context Noise Ratio.

JSON Schema Validator & Output Auditor

Validate JSON payloads against JSON Schema Draft 7 and 2020-12 standards.

GPT-4o (1.25m tok) $12.50

OpenAI GPT-4o & O3-Mini API Cost Estimator

Calculate API pricing for OpenAI GPT-4o, GPT-4o-mini, O3-mini, and O1 models.

DeepSeek V3 (10m) $2.80

Anthropic Claude 3.5 Sonnet Cost Estimator

Calculate API pricing for Anthropic Claude 3.5 Sonnet, Haiku, and Opus models.

Google Gemini 1.5 Pro & Flash Cost Estimator

Calculate API pricing for Google Gemini 1.5 Pro, Flash, and 2.0 Flash models.

Content Security Policy (CSP) Header Generator

Generate Content-Security-Policy HTTP headers to block XSS and unauthorized script execution.

default-src 'self' LOCK

script-src 'strict' PASS

HTTP Strict Transport Security (HSTS) Generator

Generate HTTP Strict-Transport-Security headers and qualify for HSTS preload submission.

X-Frame-Options Clickjacking Protection Generator

Generate X-Frame-Options DENY and SAMEORIGIN HTTP headers to prevent clickjacking.

CORS Access-Control Header Generator

Generate Access-Control-Allow-Origin, Methods, and Headers for API endpoints.

JWT Token Generator & Base64URL Encoder

Generate and encode JSON Web Tokens (JWT) with HS256 HMAC signatures client-side.

019183d0-3b02-7711-a53f-b378f4ac2e45

Time-Ordered UUID v7 Generator

Generate time-ordered RFC 9562 UUID v7 primary keys for database B-Tree index optimization.

Local Monotonic Sample

AST Syntax Highlight Postgres

SQL Query Formatter & Prettifier

Format and prettify SQL queries for PostgreSQL, MySQL, and BigQuery client-side.

SELECT u.id, u.email,
count(o.id) AS total_orders
FROM users u
WHERE u.status = 'active'
LIMIT 10;

HTML to Markdown Converter

Convert HTML markup into clean GitHub Flavored Markdown (GFM) text.

Markdown to HTML Converter

Convert GitHub Flavored Markdown (GFM) text into clean HTML5 markup.

Utility

HTML5 Canvas QR Code Generator

Generate high-resolution QR codes client-side with PNG download.

UTILITY Open ↗

Malformed { "key": 'NaN', }

JSON Repair & Malformed Syntax Fixer

Repair malformed JSON strings, single quotes, trailing commas, and unquoted keys.

Repaired { "key": 0 }

JSONPath Evaluator & Key Extractor

Evaluate JSONPath expressions against nested JSON payloads client-side.

"At minute 0 past every 6th hour"

Cron Expression Generator & Explainer

Translate 5-part cron expressions into plain English and view next run schedules.

0 */6 * * *

Base64 Text & Data URL Encoder / Decoder

Encode and decode text strings and binary file Data URLs to Base64 format.

String Case Converter (camelCase, snake_case)

Convert text strings to camelCase, snake_case, kebab-case, PascalCase, and CONSTANT_CASE.

Utility

URL-Friendly Slug Generator

Generate clean, URL-safe slugs for blog titles, products, and landing pages.

UTILITY Open ↗

XML to JSON Converter

Convert XML documents into clean, structured JSON objects client-side.

Llama-3-70B 4-bit 46.7 GB

LLM GPU VRAM Memory Requirement Calculator

Calculate GPU VRAM memory requirements for running LLMs locally or in cloud deployments.

Requires 2× 24GB GPUs

Vector Embedding Cosine Similarity Calculator

Calculate cosine similarity, dot product, and Euclidean distance between 2 vector embeddings.

JSON to CSV Converter

Convert JSON object arrays into clean CSV spreadsheets client-side.

YAML Syntax Validator & Linter

Validate YAML code syntax, lint space indentation, and detect unescaped strings.

Utility

Date Difference & Business Days Calculator

Calculate calendar days, weeks, and working business days between two dates.

UTILITY Open ↗

Compound Interest & Investment Growth Calculator

Calculate compound interest growth, annual compounding returns, and recurring monthly deposits.

SaaS CAC Payback Period & LTV Calculator

Calculate SaaS Customer Acquisition Cost (CAC) payback period in months and LTV:CAC ratios.

CSV / TSV / Pipe Delimiter Converter

Convert tabular data between Comma (CSV), Tab (TSV), Pipe (|), and Semicolon (;) delimiters.

CSV Column Extractor & Filter

Extract specific columns from CSV datasets, reorder fields, and drop unwanted columns client-side.

Cumulative Layout Shift (CLS) Audit & Fix Checklist

Audit Web Vitals Cumulative Layout Shift (CLS) score and apply CSS width/height fixes.

CSV to Excel XLSX & TSV Converter

Convert CSV files into Excel-compatible TSV spreadsheets and export table files client-side.

Excel to CSV Converter

Convert Excel TSV clipboard data and spreadsheets into clean, standardized CSV files client-side.

Windows EVTX to CSV / TXT Converter & Log Viewer

Parse Windows Event Log (.evtx, .xml, .txt) files client-side and export to CSV, TXT, or JSON.

SVG to PNG Converter & Vector Exporter

Convert SVG vector graphics and code into high-resolution PNG image files client-side.

WebP to PNG Converter

Convert WebP images into lossless PNG files client-side preserving image transparency.

JSON to YAML Converter & Config Builder

Convert JSON object structures into clean, 2-space indented YAML files client-side.

PNG to WebP Converter & Image Compressor

Convert PNG images into lightweight WebP format client-side with quality sliders.

Regex Pattern Tester & Match Explainer

Test Regular Expressions (Regex) against text client-side with match highlighting and capture group tables.

RegExp Match


/^[a-zA-Z0-9_-]+$/

Markdown Table Generator & Prettifier

Build, format, and align GitHub Flavored Markdown (GFM) tables client-side.

Base64 Image Converter & Data URL Encoder

Convert images into Base64 Data URL strings client-side for HTML/CSS embedding.

CSS Flexbox Layout Generator & Visual Builder

Build and preview CSS Flexbox layouts interactively with live alignment and gap controls.

CSS Grid Layout Generator & Visual Builder

Build and preview 2D CSS Grid layouts interactively with track size and gap controls.

HTTP Request & Response Header Inspector

Inspect, parse, and analyze HTTP request and response headers client-side with security header scoring.