Blockchain & Web3
Build smart contracts, decentralised apps and the infrastructure for digital assets.
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What is Blockchain & Web3?
Blockchain developers build applications on shared, tamper-resistant ledgers. The main work is writing and auditing smart contracts (programs that run on chains like Ethereum and its Layer-2 networks, or Solana), building the web front ends that connect to wallets, and creating infrastructure such as indexers and payment rails. In 2025–26 the field shifted from speculation toward real-world uses: stablecoin payments, tokenised assets and regulated custody. Honest note: crypto markets are volatile and hiring follows market cycles — and in Bangladesh the central bank does not recognise cryptocurrency and has warned that dealing in it may breach foreign-exchange and anti-money-laundering laws, so local work focuses on remote roles and non-trading blockchain applications.
Why it's trending now
- Clearer regulation in major markets — such as the US GENIUS Act for stablecoins (signed July 2025) and the EU's MiCA framework — brought banks, payment companies and fintechs into the space.
- Tokenisation of real-world assets (funds, bonds) and stablecoin-based cross-border payments are being piloted by large financial institutions.
- Smart-contract security is a persistent skills gap: high-profile hacks keep auditors and security researchers in demand.
- Many Web3 teams are fully remote and global, which makes the field accessible to skilled developers in Bangladesh despite local restrictions on cryptocurrency.
Job roles
Common job titles you'll see in listings, and what each one actually does.
Smart Contract Developer
Writes, tests and deploys smart contracts in Solidity (EVM) or Rust (Solana and others).
Smart Contract Auditor / Security Researcher
Reviews contracts for vulnerabilities, writes audit reports and competes in audit contests or bug bounties.
Web3 Full-Stack Developer
Builds dApp front ends and back ends that connect to wallets, contracts and indexers.
Blockchain Protocol / Core Engineer
Works on node clients, consensus, Layer-2 scaling and cryptography — highly specialised systems work.
Blockchain Data Analyst
Analyses on-chain data with SQL tools like Dune to track usage, risk and fraud.
Enterprise Blockchain / Tokenisation Engineer
Builds permissioned ledgers, custody and tokenisation systems for banks and fintechs.
Skills from beginner to advanced
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1Beginner
Start here2Intermediate
Job-ready core3Advanced
Stand outMost-requested languages & tools
What employers mention most often in current job listings for this field.
Languages
Tools & platforms
Solidity + TypeScript + Foundry covers most EVM listings. Rust is required for Solana and many protocol-level roles. Security-focused roles pay a premium.
30/60/90-day roadmap
About 1–2 hours a day. Tick goals as you complete them.
Days 1–30
Blockchain basics
Milestone: A deployed testnet contract you can explain line by line.
Days 31–60
Build dApps
Milestone: A full-stack dApp on a testnet with tests and a polished UI.
Days 61–90
Security and specialisation
Milestone: Ethernaut progress, a hackathon submission or audit-contest finding, and a security-focused write-up.
Free learning resources
All free to start. Some courses offer paid certificates — auditing is free.
- ethereum.org Developer docsEthereum Foundation · Docs · ethereum.org
- Cyfrin UpdraftCyfrin · Course · updraft.cyfrin.ioFree
- Solidity documentationSolidity · Docs · docs.soliditylang.org
- CryptoZombiesLoom · Practice · cryptozombies.ioFree
- Foundry BookFoundry · Docs · book.getfoundry.sh
- Ethernaut security challengesOpenZeppelin · Practice · ethernaut.openzeppelin.comFree
- OpenZeppelin Contracts docsOpenZeppelin · Docs · docs.openzeppelin.com
- Solana developer docsSolana · Docs · solana.com
- Bitcoin and Cryptocurrency Technologies (Princeton)Coursera · Course · coursera.orgFree to audit
- Speedrun EthereumBuidlGuidl · Practice · speedrunethereum.comFree
Portfolio project ideas
Build these in order. Put each one on GitHub with a clear README and a short demo.
Testnet token and faucet
easyDeploy an ERC-20 token on a testnet with a simple faucet page that lets friends claim tokens.
NFT certificate issuer
easyIssue verifiable course-completion certificates as NFTs on a testnet, with a page to verify them.
Escrow dApp for freelancers
mediumA smart-contract escrow that releases payment when both parties approve, with dispute timeouts and full Foundry tests.
On-chain analytics dashboard
mediumBuild a Dune dashboard tracking a protocol's usage, top users and stablecoin flows, with a written analysis.
Mini lending protocol with audit report
hardBuild a simplified lending pool with price-oracle integration, invariant/fuzz tests and a self-written audit report covering known attack vectors.
10 interview questions
Try answering out loud first, then open the short model answer.
1What is a smart contract?
A program stored on a blockchain that runs exactly as written when called by transactions; its code and state are public and changes cost gas.
2What is gas?
The unit measuring computation and storage on EVM chains. Users pay gas fees so the network is compensated and spam is limited; efficient code costs less.
3Explain a reentrancy attack.
An external call lets a malicious contract call back into the original function before state is updated, draining funds. Prevent it with checks-effects-interactions and reentrancy guards.
4Proof of Work vs Proof of Stake?
PoW secures the chain with computing power (mining); PoS uses staked tokens as collateral, using far less energy. Ethereum switched to PoS in 2022.
5What is a Layer-2?
A network that executes transactions off the main chain and posts proofs or data back to it (e.g. rollups), giving cheaper, faster transactions with Layer-1 security.
6Why are smart contracts hard to upgrade?
Deployed code is immutable. Upgrades need patterns like proxies, which add complexity and trust risks, so getting security right before deployment is critical.
7What is an oracle?
A service that brings off-chain data (e.g. prices) on-chain. Oracle manipulation is a common DeFi attack, so robust, decentralised oracles matter.
8What is the difference between ERC-20 and ERC-721?
ERC-20 defines fungible tokens (each unit identical); ERC-721 defines non-fungible tokens where each token ID is unique.
9How do you test smart contracts?
Unit tests, fuzz and invariant tests (e.g. Foundry), static analysis (Slither), forked-mainnet tests, and independent audits before launch.
10What is a stablecoin?
A token designed to keep a stable value, usually pegged to a currency like the US dollar and backed by reserves or collateral.
Resume bullet templates
Replace the [brackets] with your real numbers. Quantified results stand out to recruiters.
Developed and deployed [N] smart contracts in Solidity securing [value/users] with zero critical vulnerabilities found in audit.
Wrote [N] Foundry unit, fuzz and invariant tests achieving [X]% coverage for [protocol].
Identified [N] high/medium-severity issues in [audit contest/bug bounty], earning [ranking/reward].
Built a dApp front end with Next.js, viem and wagmi supporting [N] monthly active wallets.
Reduced gas costs by [X]% through storage-layout and logic optimisations in [contract].
Formula: action verb + what you built + tools + measurable result. Only claim numbers you can explain in an interview.
Salary & demand
Ranges vary by company, city, experience and negotiation. Always check the linked sources for the latest figures.
Bangladesh
Tk 18,345 – Tk 100,918
gross per month
No Bangladesh-specific blockchain salary data exists, so this uses Paylab's Software Engineer range (10th–90th percentile, gross monthly). Local blockchain jobs are few because Bangladesh Bank does not recognise cryptocurrency; most Bangladeshi blockchain developers work remotely for foreign teams.
Demand
Low locally due to regulatory restrictions on cryptocurrency; some software firms build blockchain solutions (supply-chain traceability, certificates) for foreign clients.
Remote (from Bangladesh)
$30,000 – $100,000
per year
Estimate. Web3 teams are often remote-first and pay globally, but compensation varies with market cycles and may include tokens. Proven auditors can earn far more through audit contests and bounties.
Demand
Moderate and cyclical. Skilled Solidity/Rust developers and especially security auditors find remote work worldwide.
Global benchmark
$134,040
US median, Software Developers, QA Analysts & Testers (BLS, 2025)
BLS has no blockchain-specific category. Blockchain pay varies widely by market conditions and seniority. Projected growth: +10% (2025–35); blockchain hiring is cyclical.
Demand
Growing again with stablecoin and tokenisation adoption by regulated finance, but more volatile than mainstream software roles.
How to read these numbers: Bangladesh ranges are Paylab's 10th–90th percentile gross monthly salaries (top product companies often pay more). Remote ranges are CareerPulse estimates informed by Arc's Bangladesh remote-developer data. Global figures are US medians from the Bureau of Labor Statistics (May 2025 data, 2025–35 projections) unless stated otherwise.
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