Infrastructure Costs Optimization
We singled out unused or ineffective elements of the system and got rid of them, redistributed computing power, and received various discounts from infrastructure providers. This allowed us to decrease the infrastructure costs from ~$40k to $22k.

IaC Implementation with AWS CloudFormation
We described, implemented, and documented new services: VPC, S3, CloudFront, ECS, LB, ACM, RDS, ECR, WAF, IAM, OpenSearch, Сloudwatch, Cognito. The resulting infrastructure is codified, transparent, documented, and suitable for automation and reuse.

Infrastructure Migration between Data Centers
We developed an infrastructure migration strategy taking into account the requirement to limit downtime to 3–4 hours. We migrated the infrastructure that was built on the Proxmox VE virtualization system (10 VMs, 10 Tb in total, including a 2 Tb 1С database) from Heztner data center to netrack. Transferred sensitive data from a 5 Tb Heztner storage to a separate server and set up backups for databases and sensitive data. The system downtime due to migration was less than 2 hours.

Logs Delivery
We built a system for guaranteed log delivery by implementing Kafka into the log collection system; we clustered and optimized ELK (standard load ~10k logs per second). As a result, we solved the problem of logs being lost due to recurrent network issues caused by high loads.

Fault Tolerance Improvement
By clustering critical system components, we increased the infrastructure’s stability and allowed its parts to be maintained separately without disrupting its work or stopping business processes.

Latency Reduction and Performance Increase
We reduced latency by fine-tuning Linux, implementing developers' ideas and new technologies. As a result, we were able to increase trading volumes and improve efficiency.

PCI DSS Compliance
We filled out a questionnaire (the infrastructural part); divided environments by sub-accounts in AWS organization; created and implemented a role model/matrix for the project (IAM), implemented MFA, granular access permissions for user groups, and a role model for the database; implemented a Password Policy, AWS WAF, secrets management (environment variables, access credentials), performed key rotation and implemented AWS KMS; configured SG. We updated and refactored VPN channels for contractors, implemented integration with processing services through encrypted tunnels. The changes made in the infrastructure improved the system’s security and allowed it to successfully pass the PCI DSS audit.

Fast Infrastructure Deployment
We significantly reduced the time needed for infrastructure deployment by implementing the IaC approach: wait time for new instances was reduced from 12–24 hours to 15 minutes. We also removed infrastructural blockers for hypotheses testing, which enabled the system's horizontal and vertical scaling in just tens of minutes.

Time to Market Decrease
We optimized the assembly and deployment of the trading bot from 4 to 1.5 minutes that increased the accuracy of responds to market changes and reduced the time needed for debugging and development.

Load Testing
We analyzed the system performance under load, checked its compliance (and non-compliance) with requirements and provided recommendations for optimization. We collected data on system performance and response time and provided recommendations for protection from DDoS attacks. By implementing our recommendations, the customer was able to ensure stable operation of the system during peak load periods.

System Design and Development from Scratch

In 3 months, we designed, developed, and implemented a fully-functional web application—an educational platform for selling electronic versions of the customer's books and using them in the learning process. We implemented all functions necessary for secure educational services. The system has become a new sales channel for the customer, with its efficiency being way above that of their competitors.

MVP Platforms for Algorithmic Trading on Crypto Exchanges

We found a solution that allowed us to separate the platform assembly from trading strategies. Implemented connectors to the major exchanges. Designed and launched a system to collect and analyze event data from the exchange. Performed several iterations of the platform’s speed and stability optimization. The platform was successfully launched, and data delivery delays from the connector to the strategy became less than a millisecond.

Pass-Through Authorization System

We developed, configured, and implemented a system of pass-through authorization and role models for all customer’s services based on JWT tokens. This allowed us to reduce the time needed to create an authorization layer and integrate all the systems by three times.

Secure Online Reader

Within a week, we developed and implemented a secure online reader for e-books with copy protection and multiple options for expanding its functionality: bookmarks, highlighting, quick navigation, going to the last read page.

Development of a Notification Module

We created a module that uses data from a file to send notifications via a dedicated portal without API integration. This solution allows the customer to save over 2000 man-hours per month. The module became a foundation for future notification platform.

Development of Authorization and Release Management Modules for an Online Game

We designed an API gateway with request authorization in Keycloak. Created a separate module for release management and artifact delivery from Nexus to CDN. The game entered the alpha testing stage, and all the necessary modules were delivered to the first users.

Organization of Testing and Quality Assurance for a Mobile Application

We built a team of QA engineers, defined and formalized requirements and user scenarios, organized testing processes (from requirements to regression testing), developed test documentation, and provided a full cycle of testing and quality control (from the MVP stage till after the product release on the market) that operates on a regular basis.

Banking Module Back-end and Integration Testing

We decomposed the system and developed test documentation, implemented processes for testing and bugs handling tasks, ran API tests, and conducted functional, integration, and regression testing of the system. Our QA engineers have been supporting the product from the MVP stage.

Load Testing

We defined and formalized main user scenarios, identified chains of actions, which simulate the real load on the site, and automated their activation with jmeter. Together with our DevOps team, we performed load testing in the customer’s test environment, collected data on the system’s performance and response time, and recommended modifications to help adapting the system to the load requirements.

Testing of Application Logic

We planned the testing process, developed scripts, and conducted functional testing of a module, which successively uses several complex logical algorithms to provide personalized goods recommendations based on information of a store customer.