Pavlos Polianidis, Developer in London, United Kingdom
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Pavlos Polianidis

Verified Expert  in Engineering

Software Developer

London, United Kingdom
Toptal Member Since
April 8, 2020

Pavlos is a technology lead and blockchain enthusiast who's worked for various companies across several industries, including Sky UK, Lloyds Bank, and Deutsche Bank. He's been involved in the design and implementation of various web-based and blockchain systems and has worked with diversified technology stacks. Pavlos has also successfully advised and engaged in several blockchain projects and has worked with diverse technology stacks.


Blockchain, Smart Contracts, Firebug
Oliver Lavender
Rust, Blockchain, Smart Contracts, Web3.js
Moduluc Corporation
Solana, Rust, Blockchain, Non-fungible Tokens (NFT), Smart Contracts




Preferred Environment

Web3.js, Ethereum, Solidity, JavaScript, Blockchain, Rust, Solana, Sui, Cosmos SDK, Zero-knowledge Proofs

The most amazing...

...project I've worked on was rebuilding the transaction page of Lloyds online banking in a short period of time.

Work Experience

Smart Contract Developer

2023 - PRESENT
  • Developed a set of custom smart contracts to allow top-ups and fund transfers from one friend to another directly within the wallet app.
  • Integrated the DEX aggregator smart contract that allows users to perform swaps directly from the app by using the best possible DEX and the best possible swap route.
  • Collaborated with the founder and CEO, advising on blockchain-related tasks and contributing to the final shape of the deliverables.
Technologies: Blockchain, Smart Contracts, Firebug

Blockchain Developer

2023 - 2023
Oliver Lavender
  • Developed Sui smart contracts in the Move language utilizing VRF randomness.
  • Worked on the Rust-based API and a PostgreSQL database storing off-chain data. The API would interact with the Sui Mainnet network.
  • Built the front-end dApp that would connect to the API and Smart.
Technologies: Rust, Blockchain, Smart Contracts, Web3.js

Solana Smart Contracts Developer

2022 - 2022
Moduluc Corporation
  • Worked on the company's new Solana programs.
  • Helped the internal dev team build some of their Solana programs.
  • Advised the founder on several tech-related tasks.
Technologies: Solana, Rust, Blockchain, Non-fungible Tokens (NFT), Smart Contracts

ERC-20 Developer

2022 - 2022
NFheroes, LLC
  • Build the NFT smart contracts for the mint drop on the EVM-based blockchain.
  • Advised the developers on several smart contract development tasks.
  • Coded the Dutch auction smart contracts for an upcoming project.
Technologies: Solidity, Blockchain, ERC-20, Smart Contracts, Ethereum

Solana Developer

2022 - 2022
ZeroTwoOne Labs PTE LTD
  • Worked on the Solana smart contracts that drive the DEX.
  • Helped add logic that would support concentrated liquidity pools.
  • Worked along with the existing team to decide upon concrete technical implementation details.
Technologies: Blockchain, Solana, Rust, Web3.js

Blockchain Developer

2022 - 2022
Avicenium Pte. Ltd. - Main
  • Designed the architecture solution for a POC to be used in the health industry.
  • Built the smart contract that allows a fair distribution of income received by the company by sharing anonymous data of their clients.
  • Developed the front end and API using technologies like Rust and React.
Technologies: Blockchain, Ethereum, Cryptocurrency, Ethereum Smart Contracts, Smart Contracts, ERC-20, Non-fungible Tokens (NFT)

Blockchain Solana Developer

2022 - 2022
Hedge Labs Inc
  • Helped the team understand the intricacies of the Solana blockchain.
  • Refactored the existing codebase to use a flexible code structure.
  • Advised on several tech-related tasks on the Solana blockchain.
Technologies: Blockchain, Solana, Rust, Anchor

Solidity Developer

2021 - 2021
MintySwap PTE LTD
  • Worked on the NFT smart contracts on the Ethereum chain.
  • Wrote several NFT and ERC-20 staking contracts.
  • Cooperated closely with the founder to help him understand the feasibility of several of his ideas.
Technologies: Ethereum, Solidity, Ethereum Smart Contracts, Blockchain, Utility Tokens

Solidity Developer

2021 - 2021
Sparkles FZCO
  • Collaborated with the internal team on daily basis to shape the final requirements of the product.
  • Implemented smart contracts for the entire NFT marketplace.
  • Helped the internal devs with blockchain-related tasks.
Technologies: Solidity, Blockchain, Web3.js, Node.js, React

Senior Solidity Developer

2021 - 2021
  • Developed ERC-20 smart contracts using Solidity and the Ethereum blockchain.
  • Worked on the smart fundraising contract that was used during their token launch.
  • Worked on staking smart contracts on the Ethereum and Polygon chains.
Technologies: Node.js, Solidity, Blockchain, Go, React

Solidity Developer

2021 - 2021
JoyPixels Inc
  • Designed a solution that utilized NFTs technologies within the existing tech stack of JoyPixels.
  • Designed smart contracts on Ethereum and built back-end integration.
  • Developed the front end with the latest JavaScript frameworks.
Technologies: Blockchain, Solidity, Ethereum, Smart Contracts, Ethereum Smart Contracts, Decentralization, ERC-20

Solidity Developer

2020 - 2020
We Cobble, LLC
  • Designed the architecture of a bridge of ERC-20 tokens into BEP20 on the BNB Smart Chain (BSC).
  • Advised the founder on the technical solutions around his initial idea.
  • Build several smart contracts, back-end services, and front-end UI comprising the cross-chain bridge.
Technologies: Solidity, Blockchain, Ethereum, Ethereum Smart Contracts

Cryptocurrency Developer

2020 - 2020
Ngrave.IO NV
  • Worked with the CTO to help him understand how to structure the back-end architecture.
  • Designed the API architecture and helped the dev team understand which part of the existing back-end code should be refactored.
  • Integrated multiple cryptocurrencies into the NGRAVE wallet.
Technologies: Blockchain, Node.js, JavaScript, Cryptocurrency

Back-end Solidity and Node.js Developer

2020 - 2020
  • Worked on an API and the inclusion of new price discovery strategies.
  • Worked along with the founder to understand the best implementation approach.
  • Helped a front-end developer with UI-related tasks.
Technologies: Solidity, Node.js, Smart Contracts, JavaScript, Ethereum Smart Contracts

Co-founder | CTO

2018 - 2020
  • Created the Transfer Checkpoint Layer (TCL) protocol: a blockchain compliance protocol that orchestrates and manages the compliance rules and verifies every token transaction between two parties.
  • Designed and developed the Concierge cabinet platform: a tokenization platform that manages and completely automates the lifecycle of security tokens.
  • Designed and implemented the token sale platform that provides full plug-and-play capabilities to support your company with raising funds through 50+ cryptocurrencies and fiat.
  • Created, designed, and delivered the Cabinet platform: a security token management platform that provides full compliance to companies with regards to managing traditional financial securities through the means of security tokens.
  • Managed a team of software engineers and organize the tasks to be delivered during each sprint.
Technologies: Microservices, Bitcoin, Go, Vault, Solidity, Neo4j, Kubernetes, Apache Kafka, React, Node.js, JavaScript

Blockchain Tech Advisor

2018 - 2019
  • Authored the technical part of the whitepaper—advising on all technical aspects needed to build a technology stack within the environmental tech and blockchain domain.
  • Designed the architecture and shaped the technical solution based on the initial ideas of the founders.
  • Represented the founders in talks with partners regarding the technical aspects of the company and the viability of the solution within the new blockchain domain.
  • Formed the product team that will deliver the project—hiring developers and designers based on their capabilities of delivering the solution that I had designed with the founders.
  • Represented the company and gave talks at international blockchain conferences.
  • Constantly evaluated the founders’ ideas and came up with a pragmatic solution that could work based on current technologies.
Technologies: Blockchain

Blockchain Tech Advisor

2018 - 2019
Various World Technologies
  • Advised on all technical aspects needed to build a technology stack within the casino and gambling domain.
  • Educated founders with generic blockchain knowledge, e.g., basic cryptographic principles, crypto wallet management, multi-signature wallet, and more.
  • Constantly evaluated the founders’ ideas and came up with a pragmatic solution that could work based on current technologies.
Technologies: JavaScript, Solidity, Cryptocurrency Wallets, Ethereum

Blockchain and Back-end Engineer

2018 - 2019
  • Worked closely with the CTO—helping with blockchain-related solutions.
  • Implemented the entire notifications system that is used in the Life Wallet. This was a system that followed the microservices approach with several Node.js services communicating with each other through the choreography pattern.
  • Helped the junior members of the team with blockchain-related tasks.
  • Contributed to the initial steps of the DevOps infrastructure using Kubernetes.
Technologies: Kubernetes, Stellar SDK, Hyperledger, Crypto, React Native, RabbitMQ, RxJS, Node.js, JavaScript

Blockchain and Smart Contract Engineer

2018 - 2019
Evident Proof
  • Created and deployed the EPT ERC20 smart contract to the Ethereum blockchain.
  • Created a set of smart contracts for the vesting plans of the company's investors.
  • Implemented a custom web-based Ethereum multi-signature wallet.
  • Responsible for deploying and distributing the EPT tokens the investors.
  • Deployed and managed the token vesting smart contracts that lock investors EPT holdings for a particular time and allows them to regularly release part of the entire fund.
  • Implemented a RESTful API that will engage with the EPT smart contract and perform the actions needed to support the system’s mechanics.
  • Created CLI tools for the company’s developers to allow them to easily interact with the multi-signature wallets, as well as token vesting and EPT smart contracts.
Technologies: Node.js, Web3.js, Solidity, Ethereum

Blockchain Advisor | Smart Contract Engineer

2018 - 2018
The Coinlab
  • Conducted a requirements gathering session, including tokenomics and business use cases.
  • Authored ERC-20 and crowdsale smart contracts using Ethereum and the Solidity language.
  • Worked with clients—helping them to design their BTC payment systems.
  • Created services around the Bitcoin ecosystem with a focus on multi-signature addresses and the secure storage of BTC funds.
  • Worked on proofs of concept (PoCs) for internal payment and bonus systems using decentralized ledger technologies.
  • Contributed to blockchain projects for companies like Audi, Bosh, and several companies in the area of real estate and invoice factoring.
  • Worked with technologies such as DApp, Web3j, Stellar, Lisk, Hyperledger, EOS, decentralized storage (IPFS, DOT protocol), and BIP32 wallets.
Technologies: RabbitMQ, Apache Kafka, Firebase, Neo4j, React, Solidity, Stellar SDK, Ethereum, Bitcoin, Node.js, JavaScript

Technology Lead

2016 - 2017
Deutsche Bank
  • Served as a member of the digital asset management tea—shaping the digital transformation initiative by building tools and software.
  • Worked along with database traders—designing and implementing automated tools to interact and trade with various counterparties via different means, such as Symphony, Bloomberg, and so on.
  • Developed various proof-of-concept projects involving technologies such as machine learning classification algorithms for fraud detection and consortium blockchain (Hyperledger) interactions.
  • Developed and maintained the database JavaScript SDK, currently used by several development teams in Deutsche Bank.
  • Built cross-platform UI components that can be seamlessly integrated in React and React Native projects.
Technologies: Hyperledger Fabric, Symphony, Bloomberg, Kubernetes, RxJS, React Native, React, Node.js, JavaScript

Lead JavaScript Engineer

2016 - 2017
Lloyds Bank
  • Worked on the LBG (Lloyds Bank Group) online banking system and the statements page of Lloyds, Halifax, and Bank of Scotland specifically.
  • Took ownership of the system from the previous team—ensuring a thorough knowledge transfer and collecting every piece of information needed to accomplish a smooth transition.
  • Found the system by interacting with members of multiple development teams across the Lloyds digital transformation department.
  • Analyzed the structure of the code and introduced several layers of abstractions (application, data flow/management, view, and so on) to make it easy to reason about.
  • Contributed to the reshaping of the ways of working in the team by advocating the use of agile principles and adapting small batch deliveries.
  • Set up an entirely new DevOps pipeline to accomplish continuous integration, continuous delivery, and continuous deployment.
  • Introduced strategies for code refactoring of the React-based application without pausing the implementation of new features.
  • Worked as part of the LBG front-end guild governing body responsible for modernizing, monitoring, and introducing good practices and patterns that are adapted across several teams within the LBG digital transformation department.
  • Contributed to the BuildIt front-end tribe initiative by giving various talks on topics like Angular 2, Elm, functional programming, advanced JavaScript async patterns, and Blockchain technologies.
  • Implemented a scaffolding tool that creates a boilerplate single-page application which teams in LBG can use to quickly bootstrap their projects.
Technologies: Kubernetes, Jenkins, Node.js, JavaScript, React

Senior JavaScript Engineer

2016 - 2016
Sky UK
  • Worked as part of the NowTV editorial team, implementing a custom CMS for managing the NowTV content.
  • Contributed to the NowTV MEAN (Angular, MongoDB, and Node.js) stack.
  • Collaborated with the NowTV content editors on different features to achieve high user experience.
  • Gathered user requirements and created user stories.
  • Contributed to shared NPM packages used by several teams in Sky.
  • Fixed front-end and back-end performance issues mainly by improving the way AngularJS was used.
  • Pioneered the start of adopting new programming paradigms, e.g., reactive and functional.
Technologies: RESTful Development, REST APIs, Node.js, MongoDB, AngularJS

Senior JavaScript Engineer

2015 - 2016
Football Radar
  • Worked in the football betting industry—implementing and maintaining highly performant real-time web-based systems.
  • Designed and implemented the SBS web application that has radically changed the way that football watchers collect data. This was a greenfield project with a duration of six months.
  • Designed and implemented the supervisor application; a highly performant real-time system that is capable of monitoring the way that watchers input their data.
  • Worked on the player model application that is being used by the watchers to collect data about individual players; it was an ongoing project that follows the microservices approach.
  • Introduced the idea of having a private NPM registry and created small reusable packages that can be shared among various projects.
  • Worked as the main contributor to the FRCSS project: a CSS framework following the ITCSS approach which we started with Harry Roberts (CSS Wizardry).
  • Maintained, fixed bugs and minimized the technical debt for various other projects.
  • Advocated for knowledge sharing sessions and organized the first JavaScript workshop for the development team.
Technologies: Apache Kafka, Apache Thrift, Scala, RxJS, ECMAScript (ES6), React

Front-end Developer

2014 - 2015
Brand View
  • Designed and implemented the widgets for
  • Served as the lead front-end developer for an ongoing project to develop a data hub platform using object-oriented JavaScript, AngularJS, React, CSS3, and C# for APIs.
  • Worked as the lead front-end developer for a platform to automate product mapping using object-oriented JavaScript, asynchronous design patterns, and DOM manipulation (jQuery, Knockout.js).
  • Spearheaded the migration to a new front-end development workflow using the latest technologies and practices (Grunt, Gulp, Bower, WebPack, Browserify, and so on).
  • Created a timeline module (named after me) which represents a generic and customizable Gantt Chart; it was built with D3.js.
  • Used object-oriented JavaScript to create a charting framework: a wrapper around Highcharts.
Technologies: Webpack, .NET, React, Node.js, JavaScript

Web Developer

2012 - 2014
Cirrus Logistics
  • Designed and implemented a set of features (site traffic) for the leading warehouse design and simulation tool, CLASS.
  • Designed and developed the security infrastructure of the company’s web-based applications using .NET WIF. It helped to win a deal with Chevron and Exxon Mobil.
  • Revamped an existing desktop app into a web-based application using Knockout.js, Durandal.js, D3.js, and object-oriented JavaScript.
Technologies: D3.js, React, AngularJS, JavaScript, OAuth, Windows Presentation Foundation (WPF), .NET, C#

Security Tokenization Platform

Tasks Accomplished:
• Created the Transfer Checkpoint Layer (TCL) protocol: a blockchain compliance protocol that orchestrates and manages the compliance rules and verifies every token transaction between two parties. The TCL creates a dynamic and upgradeable layer of rules that define the validity of any security token ownership transaction.
• Designed and developed the Concierge cabinet platform: a tokenization platform that manages and completely automates the lifecycle of security tokens. It utilizes an on-chain compliance and identity protocol that standardizes and automates how crypto-securities are created and transferred.

Vesting Smart Contracts

Tasks Accomplished:
• Implemented a custom web-based Ethereum multi-signature wallet.
• Deployed and distributed the EPT tokens for the investors.
• Deployed and managed the token vesting smart contracts that locked the investors' EPT holdings for a particular time and allowed them to regularly release part of the entire fund.
• Created CLI tools for the company’s developers to allow them to easily interact with the multi-signature wallets, as well as, the token vesting and EPT smart contracts.

Crypto Wallet

Tasks Accomplished:
• Implemented the entire notifications system that is used in the Life Wallet. This was a system that followed the microservices approach with several Node.js services communicating with each other through the choreography pattern backed by a messaging queue.
• Contributed to the initial steps of the DevOps infrastructure using Kubernetes.
• Helped with the crypto wallet implementation.
2011 - 2012

Master of Science Degree with Distinction in Web Technology

University of Southampton - Southampton, UK

2006 - 2011

Bachelor of Science Degree with Distinction in Computer Science

Aristotle University of Thessaloniki - Thessaloniki, Greece


React, Node.js, Web3.js, React Redux, REST APIs, D3.js, RxJS


RabbitMQ, Webpack, Jenkins, Bloomberg, Stellar SDK, Vault, Firebug


React Native, Angular, .NET, Windows Presentation Foundation (WPF), AngularJS, Apache Thrift, Tendermint, Parity Polkadot, Cosmos SDK


Blockchain, Apache Kafka, Kubernetes, Rancher, Docker, Hyperledger, Hyperledger Fabric, Firebase, Ethereum


JavaScript, Solidity, Rust, Go, C#, ECMAScript (ES6), Scala, F#, Python


Microservices, RESTful Development


Neo4j, MongoDB


Bitcoin, Cryptocurrency Wallets, Cryptocurrency APIs, ERC-20, Cryptocurrency Development, Cryptocurrency Payments, Smart Contracts, Ethereum Smart Contracts, Solana, Non-fungible Tokens (NFT), Aptos, Base Blockchain, Cryptocurrency, Cosmos, OAuth, Symphony, Crypto, Cryptography, Elrond, Decentralization, Anchor, Utility Tokens, Sui, Zero-knowledge Proofs

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