'/%3e%3cpath%20d='M4%206L17%206L23%2016L17%2022L4%206Z'%20fill='url(%23g)'/%3e%3cpath%20d='M4%206L17%206L20.2%2011.3L15.6%209.9L4%206Z'%20fill='%23fff'%20opacity='0.28'/%3e%3cpath%20d='M44%206H31L19%2024V44H28V26L44%206Z'%20fill='url(%23b)'/%3e%3cpath%20d='M44%206H31L19%2024V44H28V26L44%206Z'%20fill='url(%23g)'/%3e%3cpath%20d='M44%206H31L20.4%2021.8L23.2%2022.9L34.2%208.6H41.6L44%206Z'%20fill='%23fff'%20opacity='0.26'/%3e%3c/svg%3e)
virtual lab · nothing to install · free
Code Lab: practise coding in your browser
Short, friendly lessons from Easy to Hard. Type real code, press Check and get instant feedback. Sign in to save your progress and earn certificates.
Solidity IDE — write, compile & deploy
A Remix-style editor with multiple files, a built-in compiler and one-click deployment to 25 networks from your wallet. Start on a free testnet.
Open the IDE→- 1
Pick a language
JavaScript or Python are great first choices.
- 2
Read the goal
Every lesson explains what to build, with starter code.
- 3
Write & press Check
You'll know right away if it works. Stuck? Get a hint.
AI Engineering
LLM providers, agents and MCP, retrieval-augmented generation, vector search, AI security and observability.
Model providers, tokens, context windows, structured output, and evaluation.
Agent loops, ReAct, tool calling, MCP servers, and multi-agent orchestration.
Chunking, embeddings, hybrid retrieval, reranking, and grounded answers.
Prompt injection defence, PII redaction, guardrails, tracing, and cost governance.
Web3 & Smart Contracts
EVM, Solana multi-framework, Sui/Aptos Move, Starknet Cairo, Polkadot, and Stacks.
EVM contracts, Transient Storage (EIP-1153), ERC-4337 and ERC-4626.
Anchor, Pinocchio, Steel, Bolt ECS, and Token-2022 Extensions.
Object-centric Move 2024, PTBs, Kiosks, and Dynamic Fields.
Resource-oriented programming, Move Prover formal verification, and Block-STM.
STARK-provable computation, Sierra safety, and components on Starknet.
Stacks' decidable, non-Turing-complete contract language and sBTC.
Polkadot 2.0 Agile Coretime, Substrate FRAME pallets, XCM, and ink! 5.0.
Pythonic, deliberately minimal EVM language used across DeFi.
Systems & Native Languages
High-performance native development: Rust, C, Modern C++, C#, Java 21, Kotlin, and Swift.
Ownership, borrow checker, fearless concurrency, and SBF internals.
Pointers, dynamic memory management, struct alignment, and function pointers.
Modern C++20/23, RAII, Move Semantics, Concepts, Ranges, and Coroutines.
C# 12/13, .NET 8/9, Span<T>, ValueTask, LINQ, and CLR internals.
Swift 6 strict concurrency, Actors, CryptoKit, and Secure Enclave.
Java 21 LTS, Virtual Threads (Loom), Records, and Pattern Matching.
JVM internals, Spring Boot 3, Reactive Streams, and Web3j.
Modern Android, Coroutines, StateFlow, Hilt, and KMP.
Full-Stack & Application Stack
Languages and frameworks for modern dApp frontends, APIs, mobile apps, and enterprise CMS.
Type-level programming, template literal types, and branded validation.
Event loop, Metaprogramming (Proxy/Reflect), and Web Crypto API.
Server-side JS: async iterators, worker threads, and indexers.
Mobile wallets, Fabric/TurboModules, Reanimated, and WalletConnect v2.
Concurrency, channels, log/slog, and blockchain client infrastructure.
Modern Python 3.10+, dataclasses, asyncio, and cryptographic scripts.
PHP 8.x enums, readonly properties, match expressions, and Fibers.
Laravel 11 architecture, Reverb WebSockets, Queues, and Octane.
Hooks, WP_Query, custom REST endpoints, and block themes (theme.json).
Apex Governor Limits, bulkified triggers, LWC, and WITH USER_MODE SOQL.
Networking, Telecom & Payments
Core internet protocols, packet engineering, observability, eBPF, firmware, and global payment rails (UPI/SWIFT).
OSI/TCP-IP stacks, BGP/OSPF, QUIC/HTTP-3, P4 language, and 5G SA Core.
Packet dissection, Prometheus/OTel, eBPF/XDP, and embedded Linux/U-Boot.
Linux CLI (ss/nftables), Python Scapy packet crafting, and Node net/dgram.
NPCI 4-party architecture, Push/Pull flows, and comparison with SWIFT/FedNow/Pix.
Cloud, DevOps & Distributed Systems
Containers, orchestration, distributed data stores, messaging backbones, and system design.
Pods, Deployments, Ingress/Gateway API, CSI, and Custom Operators.
Linux namespaces, cgroups, and multi-stage distroless images.
Declarative HCL provisioning, remote backends, and state locking.
IAM least-privilege, Serverless Lambda, API Gateway, and DynamoDB.
ACID isolation levels, B-Tree/GIN indexes, EXPLAIN ANALYZE, and Window Functions.
In-memory data structures, Redlock distributed locking, and atomic Lua scripts.
Distributed append-only logs, partition rebalancing, and Exactly-Once Semantics.
Schema Definition Language, query planning, and DataLoader batching.
CAP & PACELC theorems, Consistent Hashing, and resilient microservice architectures.
Operating System Administration
PowerShell, Linux administration, macOS developer utilities, and shell engineering.
Questions students ask
Do I need to install anything to use the Code Lab?+
No. The editor, the checks and the Solidity compiler all run in your browser, on desktop, tablet or phone.
Is the online Solidity IDE free?+
Yes. Write, compile and deploy smart contracts to testnets like Base Sepolia and Ethereum Sepolia from your own wallet at no cost.
Is my progress saved?+
Sign in with Google or email and every solved lesson is saved to your account, so you can continue on any device.
I am a complete beginner. Where should I start?+
Pick JavaScript or Python and begin with the Easy lessons. Each one explains the goal, gives starter code and tells you when you got it right.