Position: Senior Backend Engineer (blockchain)
Company: vpteam.com.ua
Experience required: 5y
English level: upper

Looking for a Senior Backend Engineer to join Linen, a blockchain technologies-based startup being 3 yrs on the market that makes Decentralized Finance (DeFi) and self-custody of digital assets accessible to anyone. We offer you a high degree of autonomy with the power to make key tech decisions.

**What are we doing?**
We develop the Linen Wallet product - a smart contract crypto wallet and login to access Web3 and securely store crypto assets with multiple signatures (security keys). We have a mobile app for our B2C users and actively develop SDK for the B2B segment. Both are based on public blockchains, not old-school financial APIs.

Most of our early users are investors in our company. We have attracted more than $6 million of investments from leading industrial venture investors (Coinbase Ventures, Polychain Capital, HashKey) to make it convenient and safe for users to interact with Web3, including decentralized finance, games, ownable media (NFT), etc.

**Why are we doing this?**
Digital assets, like digital fiat currencies, loyalty points, in-game items issued on blockchains will be integral to most apps we use today.  Our mission it to enable people without technical background to securely store digital assets without relying on intermediaries

**How are we doing?**
Unlike regular wallets, which use seed phrases to back up and restore access to the wallet, we use smart contracts to store crypto assets and multi-signature technology to exclude a single point of failure. The multi-signature design also makes Linen Wallet more user-friendly and lowers the barriers to entry into Web3.

**How old is the project? What stage is it at?**
The project is at the stage of active development, over 3 years on the market.

**What to do in a project?**
- Build and ship reliable and secure backend applications
- Investigate complex bugs and performance issues
- Take ownership of the backend development lifecycle and codebase
- Collaborate with a cross-functional team of engineers, designers, and founders to build a highly reliable, resilient, and scalable API
- Develop and maintain automatic tests and monitors of the systems that you ship to our users and actively fix issues that may appear

**As an example, here are a couple of tasks on the backend that we dealt with:**
- Research new protocol and develop a high-level plan of integration (e.g. WalletConnect)
- Integrate with a new protocols and external APIs (e.g. API for bridging assets across chains)
- Implement an endpoint which calculates a total balance of the user across various wallets and assets
- Find a root cause of a transaction failure initiated by Linen Wallet user

**What professional skills are important to us?**
- Solid background in Computer Science
- 3+ years of experience engineering backend systems and working within a team environment in a product company or a startup
- Experience and belief in blockchain technology, NFTs, and/or decentralized finance (DeFi), understanding of cryptography concepts and algorithms
- Skilled in designing tech architecture, building, testing, releasing, and maintaining backend applications 
- Skilled in 1+ programming languages and frameworks for backend development: .NET core, Golang, Python, etc.
- Understanding of networking layers (OSI) and protocols: HTTP, HTTPS, WebSocket, etc.
- Being familiar with API architecture principles, and cloud design patterns
Experience in managing and integrating with NoSQL and relational databases (e.g. MongoDB, PostgreSQL)
- Experience in the basic setup and working with Docker, Kubernetes, CI/CD
- Knowledge and experience in building secure and common attack-resistant API.

**Our ideal candidate is:**
- A fast learner and can quickly master new technologies
- A clean code lover
- A detail-oriented troubleshooter
- Has a solid analytical and agile mindset

**Why was the position opened?**
As the number of backend tasks grows, we need to empower our tech team with more skilled engineers. 

**Current team structure?**
2 iOS, 1 Backend engineer, 1 Android developer, 1 designer, 1 product manager, 2 QA, 1 DevOps, CEO (he is a CTO as well) and 1 COO.

**Where are the people who make technical decisions on the project located?**
- Founder/CEO/CTO Alex Bazhanau is a distributed systems engineer with a vast experience in the blockchain industry
- Founder/COO Vitaly Bahachuk is primarily responsible for business development and fundraising. He is a former Wall Street investment banker
Both are based on the East Coast, US.

**The terms of employment:**
- Is there a trial period, and how long does it last? Yes, three months.
- Benefits and perks: competitive salary + equity package + equipment - pick a tech setup of your choice.
- What is the work schedule? Flexible. Overlap is till 9-10 a.m (EST). Few team calls throughout the week.
- Is it possible to work remotely? It’s a fully remote position.
- A number of vacation days? Unlimited vacation.

**The hiring process:**
Is there a test task? No.
Interview in English? Depends on a candidate. 
Who reviews the resume? CEO
How many stages of the interview, with whom?
Prescreening with a recruiter - 45 min
Technical interview + coding task - 2 hours
Culture fit interview with Vitaly - 1 hour 
Discussion of an offer with Alex and Vitaly - 1 hour.