Python
13 chaptersPython Mastery: Zero to Production
See how Python really thinks — memory, loops and async, animated.
444 tools · free courses · extensions
Free developer tools, tech courses & resources
444 private browser tools, interactive animated coding courses, and developer extensions. Fast, free, and no sign-up.
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AI & LLM
23 tools
Tokens, prompts, RAG and tool schemas
API & HTTP
16 tools
OpenAPI, REST clients, webhooks and sockets
JSON
16 tools
Format, validate and convert JSON
Text & String
43 tools
Count, convert, clean and compare text
HTML & CSS
32 tools
Formatters and visual CSS generators
Images
38 tools
Compress, convert and generate images
SEO
13 tools
Previews, meta tags and structured data
Converters
41 tools
Convert between data formats and units
Encoders & Crypto
22 tools
Encode, decode, hash and encrypt
Generators
13 tools
Generate IDs, data and boilerplate
Date & Time
15 tools
Timestamps, timezones and durations
Network & IP
31 tools
IP, subnets, headers and URLs
Color
9 tools
Convert, mix and check colors
Math & Numbers
17 tools
Calculators and number utilities
Security
17 tools
Audit secrets, headers and policies
PDF & Documents
16 tools
Read, split and convert documents
Video & Media
16 tools
Trim, compress, convert and download video
Dev Utilities
66 tools
Everyday developer helpers
Free tech courses
Animated, beginner-friendly lessons. Your progress is saved in this browser.
AI
13 chaptersGenerative AI & LLM Engineering
Tokens, embeddings, RAG and agents — explained with playable visuals.
Data
Chapters soonData Analytics & Business Intelligence
Business problem solving, spreadsheets, metrics, cohorts, statistics, and executive dashboards.
Coming soon
Data
Chapters soonSQL & Relational Database Mastery
Relational theory, bulletproof schema design, complex analytical queries, query optimization and transactions.
Coming soon
Systems
Chapters soonModern System Design & API Architecture
Watch requests travel through caches, load balancers and queues.
Coming soon
DevOps
Chapters soonAWS & Modern Cloud Architecture
VPCs, IAM policies, and serverless pipelines visualised packet by packet.
Coming soon
Systems
Chapters soonJava & Spring Boot Enterprise Mastery
JVM memory, Spring IoC, and high-throughput microservices animated.
Coming soon
Web
Chapters soonModern Full-Stack & React Internals
How React renders, updates and talks to the server.
Coming soon
AI
Chapters soonMachine Learning Foundations
Linear regression, trees, neural networks and boosting you can poke and tweak.
Coming soon
Data
Chapters soonData Engineering & The Modern Data Stack
Pipelines, columnar engines, Airflow DAGs and dbt models, visualised.
Coming soon
Systems
Chapters soonData Structures & Algorithms (DSA) Interview Mastery
Big-O, two pointers, graphs, and dynamic programming visualised step by step.
Coming soon
Systems
Chapters soonCybersecurity Essentials for Developers
See attacks happen — then learn to stop them.
Coming soon
Browser extensions
All extensionsPopular tools
See allBackground Remover
Images
Erase the background from a photo and export a transparent PNG.
Online Notepad++
Text & String
A tabbed code and text editor with syntax colours, find and replace, and auto-save.
M3U8 / HLS Downloader
Video & Media
Download an .m3u8 HLS stream and save it as a single MP4 file.
Video Editor
Video & Media
Edit video with a live preview: visual trim timeline, aspect crop, colour, text overlay and background music — export MP4, WebM or GIF in your browser.
PDF Viewer & Editor
PDF & Documents
View, search, annotate, redact, number and export PDF files offline.
JSON Formatter
JSON
Pretty-print and beautify JSON with custom indentation.
Word Counter
Text & String
Count words, characters, sentences, and reading time.
App Icon Generator (iOS, Android & Web)
Images
One image in, a ready-to-copy icon pack out for iOS, Android, web, macOS, Windows and extensions.
Image Editor
Images
Crop, rotate, filter, annotate and layer images with text, watermarks and overlays — all in your browser.
Why use Coders Hub?
Private by design
Your data never leaves the tab. No uploads, no accounts, no tracking of what you paste.
Works offline
Tools run on browser APIs, so they keep working once the page has loaded.
Instant results
No round-trips, no spinners. Output updates as fast as you type.
Curated collections
Frontend Toolkit
Everything a frontend developer reaches for daily: CSS generators, HTML formatters, JSON utilities and image optimisation.
Backend Toolkit
Payload wrangling for API work: JSON formatting, validation, conversion and text transformation.
Android Toolkit
Assets and payloads for Android development: icon and image generation, JSON handling and colour utilities.
iOS Toolkit
Everything for shipping an iPhone or iPad app: Swift models, plist and .strings conversion, universal links, privacy manifests, app icons and screen size references.
DevOps Toolkit
Config and payload tools for pipelines: YAML and JSON conversion, diffing, minification and validation.
Documents & Spreadsheets
Edit spreadsheets, documents and PDFs offline: XLSX Studio, CSV editor, Document Editor, PDF viewer/editor, OCR text and table extraction, merging and conversion.
Recently added
Python Playground — Run Python Offline
Dev Utilities
Run real Python 3 in your browser with NumPy, Pandas, Matplotlib, scikit-learn and more.
CSS Cubic-Bézier & Spring Physics Studio
HTML & CSS
Shape easing curves and physical springs with live animation previews.
SVG Path Visual Inspector & Editor
Images
Visualise, drag-edit, transform and minify SVG path d data in your browser.
SRT & VTT Subtitle Time Shifter & Editor
Video & Media
Shift subtitle timing, fix drift and fps mismatch, edit cues and convert SRT ↔ VTT.
XLSX Studio — Excel Viewer & Editor
PDF & Documents
Open, edit and save Excel workbooks offline — 50+ formulas with autocomplete, filters, conditional formatting, charts and PDF export.
SQL DDL to TypeScript / Zod / Prisma / Drizzle
Converters
Generate TypeScript, Zod, Prisma, Drizzle, JSON Schema and an ER diagram from CREATE TABLE SQL.