Sayan Kar

I am a software engineer. I have experience building several dApps with solidity and ink! for smart contracts, ReactJs for the front end, and etherjs and polkadotjs for integrations. I also have experience building robust microservices-based backend architecture with Spring Boot Java.



Enabling functionalities to be cross chainSolidity, React, material ui, Polygon (Matic), Hyperlane, Push Protocol, moonbeam


An Advanced on-chain CREDIT SCORE system for the multi-chain ecosystemSolidity, React, Defi, Rust, WASM, ccip




  • Byju's Learning App - Software Engineer
    July 2022 - Present
    • Realized significant annual savings of 60 crore through successfully replacing both Zendesk and Salesforce with an in-house solution.

    • Developed and sustained a dedicated search service, delivering rapid and precise search results at an average rate of 300 QPM.

    • Incorporated advanced features such as filtering, sorting, and free-text search support in the search service, increasing search efficiency by 30%.

    • Implemented a Kafka pipeline for asynchronous and reliable communication between services, ensuring exactly-once delivery semantics for a scale of 150K events daily.

    • Leveraged Kafka connectors to seamlessly integrate and enhance the efficiency of data flow between disparate components.

    • Engineered and implemented a rule engine processing 200K daily Kafka events, driving automation and efficiency.

    • Led Low-Level Design (LLD) efforts for the optimal system architecture of the rule engine, contributing to a 50% workload reduction.

    • Played a key role in implementing scheduler service, overseeing scheduled job execution and triggering SLA breaches, significantly improving the ticket resolution time.

    • I conducted PoCs for Elasticsearch and Kafka, demonstrating their feasibility and potential benefits.

    LLD | Spring Boot | Java | Elasticsearch | Microservices | Mongo | MySql | Apache Kafka | MVELRule | HLD | Kafka Connectors | JUnit | Mockito

  • Figment - Blockchain Contributor
    May 2021 - January 2022

    • Contributed tutorials to make decentralized applications on avalanche and
    polkadot and explained several concepts related to blockchain.
    • Links :- Build an AMM on Polkadot using Ink! , Create a Crowdfunding
    , Automated Market Maker on Avalanche , Chat dApp

  • Toppr - Software Engineer Intern
    May 2021 - July 2021
    • Developed an intuitive UI for searching and filtering across multiple entities, resulting in a 90% reduction in user search time. Introduced several other features in Toppr SchoolOs.

    • Collaborated with the backend, product, and other teams to make the user-facing product.

    ReactJs | Javascript | Redux | HTML | CSS | Saga