fleek Frontend Engineer Interview: Questions, Experience & Prep (2026)

Fleek is a Web3 infrastructure and developer platform that helps teams deploy frontends to decentralised networks (IPFS and similar) and build on-chain applications. Their engineering team ships dashboards, SDKs, and CLI tooling that developers use daily to go from code to a live, decentralised deployment.

Fleek currently has 16 open roles, and Frontend Engineer positions sit at the crossroads of modern React work and Web3 concepts like wallet connectivity, on-chain data fetching, and decentralised hosting workflows.

Candidates typically report a process of three to four conversations: a recruiter screen, a coding challenge (take-home or live), a technical deep-dive with the engineering team, and a final culture conversation. The technical bar centres on React architecture, TypeScript correctness, and comfort with Web3 libraries such as wagmi or ethers.js.

Salary ranges from the knok jobradar as of July 2026:

These are market ranges across 405 active Frontend Engineer listings. Fleek's exact bands are not publicly disclosed, so treat Glassdoor or levels.fyi community data as your best reference for the company specifically.

Candidates who have interviewed at fleek commonly report questions in three clusters: React and TypeScript depth, Web3 integration knowledge, and product thinking around developer experience.

1. Walk me through how you manage complex client-side state in a React application. What libraries do you reach for and why?
2. How would you connect a React app to a user's crypto wallet? Describe the flow from button click to signed transaction.
3. Fleek deploys frontends to IPFS. What challenges does this create for routing, environment variables, and cache invalidation compared with traditional hosting?
4. You discover a critical rendering bug in production affecting a large portion of users. Walk me through how you diagnose and fix it without a feature freeze.
5. How do you write TypeScript types for an API that returns deeply nested or variable-shape data?
6. Explain how you would implement a real-time deployment status feed in a React UI. What trade-offs exist between polling, WebSockets, and server-sent events?
7. Fleek's users are other developers. How do you test and validate that a UI change actually improves their experience?
8. Describe a time you refactored a large component tree without breaking existing functionality. What was your strategy?
9. How do you handle authentication in a decentralised app where there may be no traditional backend session?
10. What does your personal performance optimisation checklist look like for a React SPA that feels slow?
11. How would you approach building a reusable component library that needs to work across multiple Fleek products?
12. A junior engineer submits a PR with a working solution that has poor accessibility. How do you handle the review?

Q: How would you connect a React app to a user's crypto wallet?

*Situation:* At my previous company we built a token-gated dashboard where users had to connect their Ethereum wallet before accessing any content.

*Task:* I owned the wallet connection flow end to end, including handling multiple wallet providers and network switching.

*Action:* I used wagmi and RainbowKit to abstract provider differences. I built a custom hook that wrapped the connect flow, watched for chain mismatches, and surfaced clear error states to the user ('Switch to Ethereum Mainnet' instead of a raw hex error code). I also persisted the last-used connector in localStorage so returning users were reconnected automatically.

*Result:* Drop-off on the connect screen fell noticeably in our internal analytics, and support tickets about 'wallet not working' dropped in the first sprint after release.

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Q: Walk me through how you manage complex client-side state in a React application.

*Situation:* We were building a multi-step deployment wizard with many form fields, async validation, and the ability to jump back to earlier steps without losing data.

*Task:* I needed a state management approach that was testable, avoided unnecessary re-renders, and was easy for the rest of the team to follow.

*Action:* I chose Zustand for global wizard state and kept local transient UI state (like 'is this dropdown open') in component-level useState. I wrote a clear slice per step, exposed only the actions each step needed, and added devtools middleware so the team could inspect state transitions during code review.

*Result:* QA reported zero state-corruption bugs across the wizard during the full regression cycle, and onboarding a new engineer to the feature took under a day because the state shape was self-documenting.

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Q: How do you handle a critical production bug affecting many users?

*Situation:* A deploy went out on a Friday afternoon that broke the primary navigation for users on Safari browsers.

*Task:* I was the on-call engineer and needed to assess severity, communicate to stakeholders, and ship a fix quickly.

*Action:* I confirmed scope using our error tracking tool, then rolled back the deploy to stop the bleeding. While the rollback was live I reproduced the issue locally in Safari, traced it to a CSS gap property with a known Safari incompatibility, and wrote a regression test before pushing the fix. I posted a short incident summary in Slack for the team.

*Result:* The total user impact window was short. The regression test caught a similar issue three sprints later before it ever reached production.

For architecture and design questions, lead with the constraint you are solving for (performance, maintainability, team size), then name the pattern or library, then explain the trade-off you consciously accepted. Interviewers at product-led companies like fleek care more about your reasoning than whether you picked the 'right' tool.

For Web3-specific questions, show that you understand the user-facing implications, not just the code. Wallet errors, gas estimation failures, and RPC rate limits all show up as confusing UI states if you do not handle them. Frame your answer around what the user sees at each failure point.

For debugging and incident questions, use a three-part structure: contain (stop the bleeding), diagnose (find the root cause), and prevent (close the loop with a test or process change). This shows operational maturity beyond just coding skill.

For 'how would you improve X' questions, clarify the goal first, identify who the user is, name the pain point, propose your solution, and evaluate trade-offs. Keep it conversational, not formulaic.

For behavioural questions, keep the Situation and Task combined to two or three sentences. Spend most of your answer on Action and quantify the Result even loosely ('reduced by roughly half', 'cut to under a day'). Specific beats vague every time.

Fleek sits at the edge of traditional frontend engineering and Web3 infrastructure. Interviewers are typically looking for four things.

Genuine Web3 curiosity. You do not need to have shipped many dApps, but you should understand why decentralised hosting changes how you think about routing, environment config, and cache control. Candidates who treat Web3 as a checkbox tend to be filtered out early.

Strong React and TypeScript fundamentals. Fleek's product surface is large and fast-moving. They want engineers who can own a complex component or hook independently, write types that actually prevent bugs (not just silence the compiler), and make sensible trade-offs between abstraction and simplicity.

Developer empathy. Fleek's users are other developers. Interviewers want to see that you think about API ergonomics, error messages, and documentation as first-class parts of a feature, not afterthoughts. Mentioning DX (developer experience) explicitly in your answers tends to land well.

Ownership and communication. With 16 open roles the team is growing quickly. They want people who raise blockers early, write clear PR descriptions, and give direct feedback in code review without being harsh. Behavioural questions often probe for exactly this.

Week 1: Sharpen your React and TypeScript fundamentals.
Review how useEffect, useMemo, and useCallback work under the hood. Practice writing generic utility types and mapped types in TypeScript. Build or revisit a small project using Zustand or Jotai so you can speak to state management trade-offs from real experience, not just from documentation.

Week 2: Build your Web3 baseline.
If you have not used wagmi or ethers.js before, follow their official documentation to build a simple wallet-connect flow. Read about IPFS content addressing and why content IDs replace traditional URLs. Understand what ENS does and why it matters for frontend routing in a decentralised app.

Week 3: Study fleek's product directly.
Sign up for a free fleek account and deploy a small React app. Note where the UI is smooth and where it confused you. These observations become concrete talking points in 'improve our product' or DX questions, and they signal genuine interest to interviewers.

Before the interview, prepare two or three STAR stories covering: a complex technical problem you owned end to end, a time you improved a process or DX, and a conflict or difficult code review. Have questions ready for the interviewer about the team's deployment process, how they handle breaking changes in their SDK, and what a typical sprint looks like.

Knok checks 150+ job sites nightly, applies to Frontend Engineer roles that match your resume, and messages HR directly on your behalf, so you can spend this preparation time actually preparing instead of scrolling through listings.

Treating Web3 as optional. Even if a role description emphasises React, fleek's product is deeply tied to decentralised infrastructure. Candidates who have not explored wagmi or IPFS basics come across as unprepared for the company's actual context.

Over-engineering the coding challenge. Fleek interviewers typically want clean, readable code over a maximally clever solution. A clear component with sensible props and good naming beats a heavily abstracted one that takes extra time to explain.

Giving vague behavioural answers. Saying 'I improved performance' without a concrete before-and-after reads as filler. Even 'it went from noticeably slow on mobile to smooth' is more convincing than a generic claim.

Not asking questions. Candidates who ask nothing signal low interest. Prepare at least two specific questions about the team, the product roadmap, or the engineering process. Asking about something you noticed while actually using the fleek product is a particularly strong signal.

Confusing wallet authentication with traditional auth. A common slip is describing a Web3 auth flow using session-cookie language. Be precise: wallet-based auth uses a signed message to prove key ownership, not a username-password exchange. Muddling this raises doubts about your Web3 depth.

Skipping the 'why' in architecture answers. Naming a library is not an answer. Explain what problem it solves in your specific context and what you gave up by choosing it.