Todor Karparov

Senior Software Engineer
Bulgaria (UTC+2)· Remote — flexible from EU to US-East hours· [email protected]· linkedin.com/in/todor-karparov

Profile

Backend engineer focused on distributed systems and payments infrastructure on AWS. At Runa I lead technical initiatives in the consumer domain — high-availability, real-time gift-card fulfillment — driving architecture decisions, design reviews, and observability practices. Promoted to Senior within two years; happiest owning problems end-to-end, from design through rollout to customer impact.

Skills

TypeScriptPythonGo JavaAWS · LambdaAWS · Step Functions AWS · DynamoDBAWS · EKSAWS · CloudWatch TerraformCloudflare Workers PostgreSQLMySQLReactVue.js

Experience

Software Developer → Senior Software Engineer (promoted Jan 2026), Runa

Nov 2023 — Present · Remote
Runa — payments network for digital value (gift cards and prepaid cards); the consumer team owns real-time fulfillment. TypeScript, Python, Go, AWS (Step Functions, Lambda, DynamoDB, EKS, CloudWatch), Terraform, Cloudflare (Workers, WAF, R2)
  • Lead technical initiatives in the consumer domain — high-availability systems for real-time gift-card fulfillment; drive architectural decisions and design reviews, mentor engineers on observability best practices
  • Lead the prepaid (debit) card initiative (100k+ cards issued to date) — designed the card lifecycle orchestration and the business observability around it
  • Architected and built a collaborative authorization router — a long-running Go service on EKS, chosen over our Node.js/Python serverless defaults after evaluating runtimes — that resolves each card authorization from the issuer to the owning customer and returns their decision within a hard 2s, fail-open budget (~100 req/s at launch); delivered under a tight timeline for Runa's largest customer
  • Reduced perceived latency ~70% (50s → 15s) on the most critical user journey by redesigning the flow around asynchronous background processing
  • Led the migration from a legacy Python monolith to serverless orchestration (Step Functions, Lambda, DynamoDB); built a testing framework on Step Functions Local enabling confident validation of data transformations and failure recovery
  • Improved throughput ~20% on a key service by optimizing serialization; introduced MSW integration tests for the consumer web app and third-party clients
  • Automated incident-response and operational procedures, cutting resolution time 50%+ in key workflows; team SME for AWS CloudWatch and observability
  • Bar Raiser; lead both coding and system-design interviews; created the System Design interview preparation resource used by the recruitment team

Software Developer, SolarEdge Technologies

Jul 2022 — Nov 2023
Java 17, Spring, Hibernate, REST, MySQL, Linux, Bash, TestContainers
  • Drove features end-to-end from PRD through design to implementation; introduced TestContainers integration tests to bolster confidence in shipped changes
  • Led the introduction of MobX and MVVM architecture in a large web app, increasing readability, maintainability, and development speed
  • Improved DevX and development speed by introducing WSL2 + Linux local development through a comprehensive setup script and guide

Software Developer (Intern → Junior), Paysafe

Feb 2021 — Jul 2022
Java 11, Angular 10+, MySQL, Oracle RDBMS
  • Improved the customer bank-account verification flow via a third-party vendor integration; implemented IP-based geolocation with MaxMind
  • Built an internal hiring tool for the HR department, replacing paid subscriptions

Education

BSc Computer Science
Sofia University “St. Kliment Ohridski” (FMI) · 2018 – 2022 · Sofia

Languages

English — C2  ·  German — C1  ·  Bulgarian — native