Technical interview guide

Web3 Development Tooling & Testing

The frameworks, testing practices, and node infrastructure a blockchain developer actually uses day to day.

Read: 48 min
Practice MCQs: 25
Interview QA: 25
Edition: v3
Editorial status: Reviewed
Relevant for: Blockchain Developer

Scope: Solidity compiler and security documentation; Hardhat 3; Foundry Forge; ethers v6; EIP-1193; EIP-712; Sourcify verification guidance reviewed 2026-09-04.

Interview QA

Treat each question like a live interview question: answer out loud first (structure, assumptions, tradeoffs), then open the model answer to spot gaps and rehearse a tighter follow-up.

Curated: 2026-10-05 · Written: 2026-10-05 · Reviewed: 2026-10-03

QA-1

Build a reproducible contract compilation pipeline.

QA-2

Review a production compiler configuration.

QA-3

Version contract artifacts for client consumers.

QA-4

Design unit tests for a privileged withdrawal.

QA-5

Fuzz a tokenized vault conversion.

QA-6

Build an invariant harness for a lending protocol.

QA-7

Differential-test protocol math.

QA-8

Create a mainnet-fork integration suite.

QA-9

State the evidence boundary of a fork test.

QA-10

Use coverage responsibly in CI.

QA-11

How do you build a custom static analysis detector to identify protocol-specific vulnerabilities in CI?

QA-12

Specify a formal property for withdrawals.

QA-13

Build a consistent portfolio read.

QA-14

Preflight a user transaction.

QA-15

Design a reorg-safe event indexer.

QA-16

Implement resilient wallet-provider state.

QA-17

Design a permit-like signed authorization.

QA-18

Create a reviewable deployment pipeline.

QA-19

Use deterministic deployment safely.

QA-20

Automate post-deployment verification.

QA-21

Validate an upgrade before execution.

QA-22

Separate deployment and operations authority.

QA-23

Manage a contract toolchain supply chain.

QA-24

Set meaningful gas and code-size gates.

QA-25