Career roadmap
Blockchain Engineer
Write code that controls money and cannot be patched quietly. Security discipline is the whole job.
Before you start Blockchain
- Strong programming fundamentals in any language
- Understanding of hashing and public key cryptography basics
- Backend and API experience
How the systems work
Understand the machine before writing code that runs on it.
Everything in this field rests on a small set of primitives.
- Hash functions and Merkle trees
- Elliptic curve signatures
- Key derivation and wallets
- Commitment schemes
Why the ledger agrees, and what it costs to make it agree.
- Proof of work and proof of stake
- Finality and reorganisations
- Peer-to-peer gossip and propagation
- Fork choice rules
The virtual machine determines what your code can and cannot do.
- EVM execution model and gas
- Accounts, storage and state
- Transactions, calldata and receipts
- Alternative VMs and their trade-offs
The interfaces almost every application is built on.
- Fungible and non-fungible standards
- Approvals and allowance patterns
- Metadata and interface detection
- Upgrade patterns and proxies
Where most current activity and most current hiring is.
- Rollups: optimistic and validity proofs
- Data availability
- Bridging and cross-chain messaging
- Trade-offs between layers
BuildBuild a minimal blockchain from scratch: blocks, hashing, signatures and a consensus rule.
Smart contract development
Writing contracts that are correct, cheap and impossible to quietly fix later.
The dominant language, with a set of sharp edges you must know by heart.
- Types, storage layout and packing
- Visibility, modifiers and inheritance
- Errors, reverts and custom errors
- Assembly and low-level calls
Established patterns exist because the alternatives lost money.
- Checks-effects-interactions
- Pull over push payments
- Access control and role management
- Upgradeability patterns and their risks
Users pay for every inefficiency, so this is a real product concern.
- Storage versus memory costs
- Loop and batch design
- Packing and bit manipulation
- Measuring with gas reports
Test standards here are far higher than in ordinary application code.
- Foundry and unit testing
- Fuzz testing and invariants
- Fork testing against mainnet state
- Coverage and mutation testing
A mature toolchain that interviews expect fluency in.
- Foundry and Hardhat workflows
- Local nodes and forked environments
- Deployment scripting
- Verification and source publishing
BuildShip a non-trivial contract system to a testnet with a full test suite and gas report.
Security
The defining discipline. Deployed code is public, immutable and holds funds.
A well-documented catalogue of ways contracts have lost money.
- Reentrancy and cross-function reentrancy
- Integer and rounding errors
- Access control failures
- Oracle manipulation
Attacks where every transaction is valid but the outcome is theft.
- Flash loan attacks
- Price oracle manipulation
- MEV, sandwiching and front-running
- Governance attacks
The highest-paid specialisation in the field.
- Systematic review methodology
- Threat modelling a protocol
- Writing findings with severity
- Static analysis and symbolic execution
Increasingly expected for high-value protocols.
- Invariant specification
- Symbolic execution tools
- Property-based verification
- Limits of formal methods
Key management failures cause as many losses as code bugs.
- Multisig and timelock design
- Key management and hardware wallets
- Incident response for live contracts
- Pausability and emergency procedures
BuildComplete a set of security challenges, then audit someone else's contract and write the report.
Applications and integration
Contracts are only part of a product. The rest is ordinary engineering done carefully.
Wallet interaction and transaction lifecycle handling.
- Wallet connection and signing
- Transaction states and confirmations
- Handling reverts and user rejection
- Chain switching and network handling
Reading chain state efficiently is its own engineering problem.
- Event indexing and subgraphs
- Handling reorganisations in indexes
- RPC providers and rate limits
- Caching chain data
Composability is the field's strength and its largest attack surface.
- Automated market makers
- Lending and collateral mechanics
- Composability risk
- Integration testing against real protocols
Where the more stable, better-paid corporate roles are.
- Permissioned ledger platforms
- Tokenisation of real assets
- Identity and compliance integration
- Regulatory considerations
Most of a blockchain product is conventional backend engineering.
- Keeper and automation services
- Oracle integration
- Transaction relaying and gas management
- Monitoring on-chain state
BuildBuild a full application: contracts, indexer, frontend, and a documented failure-handling story.
Interview preparation
Interviews are security-heavy. Expect to find bugs in contracts you have just been shown.
The core interview: here is a contract, find the vulnerability.
- Systematic contract review under time pressure
- Explaining exploitability precisely
- Proposing a correct fix
- Severity assessment
Language mechanics and gas questions, asked precisely.
- Storage layout and packing
- delegatecall and proxy mechanics
- Gas cost reasoning
- Common compiler pitfalls
Design a mechanism, then attack your own design.
- Incentive design
- Failure and edge case analysis
- Upgrade and governance strategy
- Economic attack surface
Consensus, finality and cryptography questions.
- Consensus mechanism trade-offs
- Rollup security models
- Signature schemes
- Reorg handling
Audit competition results are the strongest credential in this field.
- Audit competition findings
- Deployed contracts with tests
- A written audit report
- Open-source protocol contributions
BuildA public portfolio: audited contracts, competition findings, and a written audit report.
Blockchain tools on your CV
- Solidity
- Foundry
- Hardhat
- Slither
- The Graph
- viem / ethers
- Tenderly
What Blockchain employers ask to see
- Deployed contracts with a full test and fuzz suite
- Findings from public audit competitions
- A written audit report on someone else's code
- A gas optimisation case study with measurements
Smaller and more volatile than mainstream engineering, concentrated in protocol teams, exchanges, and increasingly in banks working on settlement and tokenisation. Security-focused roles command very high rates because mistakes are irreversible.
Content last reviewed 2026-08-31. Guidance only — no institute or paid placement is endorsed anywhere in this book.