Sebastian Karasiewicz

Senior Software Developer at Dalip AI | Full-Stack Engineer | Cloud-Based Systems | Scalable Web Platforms

Senior Software Developer at Dalip AI, building an AI-powered platform to transform 1-on-1 meetings. Full-Stack Engineer with over 12 years of experience delivering scalable, cloud-native applications across finance, SaaS, e-commerce, and real estate. Specialized in modern web architectures using React, Next.js, and TypeScript, with strong backend expertise in Python, Go, and Java. Daily practitioner of AI-driven development, leveraging Claude and other AI tools for enhanced productivity and code quality.

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Technical Skills

TypeScriptJavaScriptReactNext.jsNode.jsPythonDjangoFlaskGoRubyRailsRESTful APISQLNoSQLPostgreSQLMySQLMongoDBAWSAWS LambdaS3SNSSESAPI GatewayAWS ServicesGCPGoogle App EngineCloud DatastoreCloud StorageAzureVercelDockerGitGitHubE2EUnit TestingSEOTailwindshadcn/uiAlgoliaContentful

Work Experience

Senior Software Developer
Dalip AI
09/2025 - Present
- Building an AI-powered platform to transform 1-on-1 meetings between managers and direct reports
- Developing full-stack features with focus on scalability and user experience
- Tech stack: React, Next.js, TypeScript, AI/ML integrations
Senior Full-Stack Engineer
Diageo
05/2024 - 09/2025
- Migrated landing pages for brands like Yeni Raki and Johnnie Walker to a modern, SEO-optimized architecture using React and Next.js
- Unified frontend architecture across multiple brand websites
- Led the testing strategy with robust unit and E2E test coverage
- Contributed to internal tooling and frameworks
- Tech stack: React, Next.js, Tailwind, Vercel, Contentful, Algolia
Senior Lead Software Engineer
SoftKraft
11/2019 - 05/2024
- Switchboard: Led the frontend team for an enterprise-grade network cost optimization tool
- VideoTranscoding: Built a serverless video processing pipeline on AWS
- CAAS: Developed an event-driven microservice in Go for transforming and routing communications
- MLSWorldwide: Created a backend API and ingestion engine for a global property aggregator
- Tech stack: React, Python, Django, Go, Docker, AWS (SES, SQS, SNS, Lambda, API Gateway, S3)
Senior Full-Stack Engineer
Sofomo
02/2017 - 02/2020
- JUUL: Extended a Rails-based system for selling e-cigarettes, focused on feature development and stability
- Voyajoy: Developed APIs for listing synchronization across Airbnb, Booking.com, FlipKey
- Strings: Built a social platform combining features of Facebook and Twitter (X)
- Tech stack: Python (Django, Flask), React, Ruby on Rails, PostgreSQL, InfluxDB, Docker, Azure Cloud
Software Development Manager
PLUSGPS Q4B Sp. z o.o. Sp. k.
01/2016 - 12/2016
- StaffSupervisor: Developed backend for monitoring telemarketer activities with Go + React
- Beecron: Delivered beacon-driven indoor navigation backend
- TachoOnline: Built APIs for driver work-time tracking based on tachograph data
- Tech stack: Go, Google App Engine, Cloud Datastore, Cloud Storage, Docker
Backend Java Developer
Coderion
01/2015 - 12/2015
- IdeaFaktor: Built and maintained a factoring platform for financial institutions
- Tech stack: Java, Apache Wicket, Hibernate, PostgreSQL
Backend Developer
Selleo
03/2014 - 09/2015
- PipelineDeals: Contributed to a CRM platform for sales teams
- Tech stack: Ruby on Rails, RSpec, MySQL, CoffeeScript, Backbone.js, SASS
Backend Developer
Merlin.X
09/2012 - 03/2014
- Merlin X: Worked on backend feature development and system upgrades for a major B2B travel reservation system
- Tech stack: PHP, JavaScript, jQuery, MySQL

Get In Touch

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Languages

Polish – Native

English – C1

Japanese – Beginner

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Sebastian Karasiewicz

Senior Software Developer at Dalip AI | Full-Stack Engineer | Cloud-Based Systems | Scalable Web Platforms

Technical Skills

Work Experience

Senior Software Developer

Senior Full-Stack Engineer

Senior Lead Software Engineer

Senior Full-Stack Engineer

Software Development Manager

Backend Java Developer

Backend Developer

Backend Developer

Get In Touch

Technical Skills

Work Experience

Senior Software Developer

Senior Full-Stack Engineer

Senior Lead Software Engineer

Senior Full-Stack Engineer

Software Development Manager

Backend Java Developer

Backend Developer

Backend Developer

Get In Touch