Daniel Jasinski-Senior Software Engineer
Check rate
Experience
Senior Software Engineer
Sii Poland
- Built a microservices-based backend for tracking system using Go (Golang), achieving sub-100ms response times.
- Implemented gRPC for real-time communication between microservices, reducing latency by 40%.
- Designed and optimized PostgreSQL schemas for transaction processing and user account management.
- Set up Apache Kafka for event sourcing in a fraud detection system, enabling real-time transaction analysis.
- Implemented serverless functions using AWS Lambda for processing transaction notifications.
- Configured AWS RDS with read replicas for high availability and performance.
- Designed and implemented a CI/CD pipeline using GitHub Actions, enabling frequent and reliable deployments.
- Set up Prometheus and Grafana for monitoring transaction processing and system health.
- Automated infrastructure provisioning using Terraform, reducing setup time by 60%.
- Developed an event-driven notification system using Apache Kafka, processing 1M+ events daily.
- Built a RESTful API for order management using Python Flask, ensuring seamless integration with mobile apps.
- Implemented Redis for caching restaurant menus and order statuses, reducing database load.
- Designed and optimized DynamoDB tables for storing real-time order data.
- Set up RabbitMQ for asynchronous communication between order processing and delivery services.
- Deployed the application on AWS ECS Fargate, ensuring scalability during peak hours.
- Configured AWS SNS for sending push notifications to delivery partners and customers.
- Implemented AWS Lambda for processing payment status updates and refunds.
- Set up centralized logging using the ELK stack for troubleshooting and analytics.
- Designed and implemented a disaster recovery plan using AWS Backup and cross-region replication.
- Developed a microservices-based backend for a SaaS platform using Node.js and Express.js, ensuring scalability.
- Implemented Redis for caching frequently accessed user data, reducing API response times.
- Designed and optimized PostgreSQL schemas for storing user data and application settings.
- Set up Apache Kafka for event-driven updates to user dashboards and notifications.
- Deployed the application on Kubernetes (EKS) for high availability and scalability.
- Configured AWS SNS for sending push notifications to users.
- Implemented AWS Lambda for processing user uploads and transformations.
- Set up centralized logging using the ELK stack for troubleshooting and analytics.
- Designed and implemented a disaster recovery plan using AWS Backup and cross-region replication.
- Configured Prometheus and Grafana for monitoring API performance and system health.
Software Developer
Connected Digital Ltd
- Developed backend microservices in Golang for image metadata management and user content feeds, leveraging Go’s high concurrency support.
- Built a serverless image processing pipeline using AWS Lambda and S3 for a photo-sharing app.
- Designed and optimized DynamoDB tables for storing media metadata and user interactions.
- Set up Apache Kafka for event-driven updates to user feeds and notifications.
- Deployed the application on Kubernetes (EKS) for high availability and scalability.
- Configured AWS CloudFront for CDN to improve media delivery times for global users.
- Implemented AWS Lambda for processing media uploads and transformations.
- Set up centralized logging using the ELK stack for troubleshooting and analytics.
- Built high-throughput APIs using Golang for real-time shipment tracking, replacing performance bottlenecks in legacy Python code.
- Developed an event-driven architecture using AWS EventBridge and SQS for a logistics tracking system.
- Built a RESTful API for shipment tracking using Python Flask, ensuring seamless integration with mobile apps.
- Implemented Redis for caching frequently accessed shipment data, reducing database load.
- Designed and optimized DynamoDB tables for storing real-time shipment data.
- Set up RabbitMQ for asynchronous communication between shipment processing and tracking services.
- Deployed the application on AWS ECS Fargate, ensuring scalability during peak hours.
- Configured AWS SNS for sending push notifications to drivers and customers.
- Implemented AWS Lambda for processing shipment status updates and notifications.
- Set up centralized logging using the ELK stack for troubleshooting and analytics.
- Designed and implemented a disaster recovery plan using AWS Backup and cross-region replication.
Software Developer
University of Information Technology and Management
- Developed a GraphQL API for a social media app, reducing over-fetching and improving client-side performance by 30%.
- Implemented WebSocket-based real-time notifications for user interactions (likes, comments, messages).
- Designed a microservices architecture using Go (Golang) for high-performance backend services.
- Utilized Apache Kafka for event-driven updates to user feeds and notifications.
- Set up MongoDB for storing user-generated content, ensuring scalability and flexibility.
- Implemented OAuth2 and JWT-based authentication for secure user access.
- Deployed the application on Kubernetes (EKS) for seamless scaling during peak traffic.
- Configured Datadog for end-to-end observability, enabling quick troubleshooting of performance bottlenecks.
- Developed a high-performance backend for a mobile gaming app using Go (Golang), achieving low-latency gameplay.
- Implemented Redis for caching frequently accessed game data, reducing API response times.
- Designed and optimized DynamoDB tables for storing real-time game data.
- Set up Apache Kafka for event-driven updates to game state and player interactions.
- Deployed the application on Kubernetes (EKS) for high availability and scalability.
- Configured AWS CloudFront for CDN to improve game asset delivery times for global users.
- Implemented AWS Lambda for processing in-game purchases and receipts.
- Set up centralized logging using the ELK stack for troubleshooting and analytics.
Industry experience
See where this freelancer has spent most of their professional time.
Experienced in Information Technology, Banking and Finance, Food and Beverage, Transportation, and Media and Entertainment.
Business area experience
See which departments and functions this freelancer has contributed to most.
Experienced in Information Technology and Supply Chain Management.
Summary
Senior Backend Engineer with over 12 years of hands-on experience delivering robust backend systems and infrastructure for both startups and large-scale platforms. Focused on building reliable, maintainable services using Go, and also well-versed in Python, Java, and Node.js. Skilled in architecting microservices and event-driven systems, with a strong emphasis on performance tuning and operational stability. Experienced in DevOps practices including CI/CD pipelines, infrastructure provisioning, and cloud-native deployments on AWS. Brings a systems-thinking mindset to backend engineering—designing solutions that are efficient, scalable, and easy to evolve.
Skills
- Backend Development: Graphql, Grpc, Rest Apis, Java, Go (Golang), Python, Node.Js (Typescript, Javascript), Apache Kafka, Rabbitmq, Prometheus, Grafana, Datadog, Elk
- Aws: Ec2, Ecr, Ecs, Cks, Fargate, Api Gateway, Eventbridge, Sqs, Sns, Lambdas, Cdk, S3, Dynamodb, Rds
- Devops: Docker, Kubernetes, Github Actions, Ci/Cd Designing, Aws Ec2, Ecr, Ecs, Eks, Terraform
- Database: Postgresql, Mongodb, Mysql, Redis, Dynamodb, Cassandradb, Neo4j
Languages
Education
University of Information Technology and Management
Master’s degree, Computer Science · Computer Science · Rzeszów, Poland
University of Information Technology and Management
Bachelor’s degree, Computer Science · Computer Science · Rzeszów, Poland
Statistics
Experience
Expertise
Qualifications
Profile
Frequently asked questions
Have questions? Find more information here.
Daniel is based in Rzeszów, Poland.
Daniel speaks the following languages: Polish (Native), English (Advanced).
Daniel has at least 15 years of experience. During this time, Daniel has worked in at least 2 different roles and for 3 different companies. The average length of individual experience is 5 years and 11 months. Note that Daniel may not have shared all experience and actually has more experience.
Based on recent experience, Daniel would be well-suited for roles such as: Senior Software Engineer, Software Developer.
Daniel's most recent position is Senior Software Engineer at Sii Poland.
In recent years, Daniel has worked for Sii Poland.
Daniel is most experienced in industries like Information Technology, Banking and Finance, and Food and Beverage. Daniel also has some experience in Transportation and Media and Entertainment.
Daniel is most experienced in business areas like Information Technology and Supply Chain Management.
Daniel has recently worked in industries like Banking and Finance, Food and Beverage, and Information Technology.
Daniel has recently worked in business areas like Information Technology.
Daniel holds a Master in Computer Science from University of Information Technology and Management and a Bachelor in Computer Science from University of Information Technology and Management.
The availability of Daniel needs to be confirmed.
Daily rate distribution
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Average rates for similar positions
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The average daily rate is the mean of all daily rates from recent contracts of comparable freelancers on our platform.
The median daily rate is the middle value of all daily rates — half of comparable freelancers charge less, half charge more. Unlike the average, it is barely affected by outliers.
Calculated based on our freelancers’ daily rates as of 7 Sep 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
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