Gerasimchuk Mikhail

Golang development as part of work on the DocuWalk and Document GPS products. Creating application skeletons and adapting clean architecture practices. Improving CI/CD processes in GitLab, evolving monitoring based on Prometheus and Grafana, optimizing system performance in database operations, and enhancing the development ecosystem built on AWS and Kubernetes. Developing the first version of a RAG system based on AWS components, with further work on the features and evolution of this AI Trust & Governance platform, Mithra AI.

• Implemented the E-Signature capability in the product and adopted a Centrifugo WebSocket component to power the real-time collaboration feature
• Built a first version of the RAG solution on top of AWS components and shipped it in the Mithra AI Beta
• Built the backend CI/CD from scratch and completed the org-wide GitLab migration
• Accelerating library upgrades by 15x+ and reducing the effort from the whole team to a single developer
• Established observability across the org - Sentry error tracking, Prometheus/Alermanager alerting, and continuous profiling with an alert auto-assignment mechanism that pings the responsible developer in Slack
• Built a live-rebuilding Kubernetes debug mode that cut root-cause localization from ~1 day to tens of minutes
• Cut false-positive alerting via a "Silences as code" approach and reduced false-positive QA autotests through CI/CD tuning
• Created a custom Grafana datasource for MongoDB slow logs, avoiding a $300+/month enterprise Grafana cost

Roles: Lead Golang developer, Tech Lead

Technologies: GoLang, gRPC, protobuf, WebSockets, REST, Prometheus, Prometheus Alertmanager, Docker, K8S, MongoDB, Elasticsearch(AWS OpenSearch), Kafka, Redis, BlazeMeter, JMeter, Grafana, Kibana, GitLab, Microservices, AWS(X-Ray, CloudWatch, VPC, MSK, EKS, Bedrock), Hyperledger.

I've written 0 lines of code for AWS, but my inbox contains over 300 email correspondences with my AWS Shield development team manager and employees of the immigration service.

Unfortunately, due to circumstances beyond my control and those of Amazon, I was unable to start working on the AWS Shield project because the Canadian immigration agency did not approve my work visa within the specified timeframe.

Nevertheless, I still decided to reflect this experience into my career path, as I consider it an authoritative confirmation of some of my skills.

• I successfully completed all three rounds of interviews, including the loop, and received the final job offer on August 16, 2022, to join the AWS Shield team, which I accepted.
• I traveled to Kazakhstan to take the IELTS language exam and prepare numerous other documents for immigration to Canada.
• I submitted the entire immigration document package.
• I signed numerous papers and contracts from AWS and even reserved internal mail and a badge.
• However, after six months of active collaboration with the Canadian immigration agency and the immigration assistance outsourcing agency Vialto, my documents stalled at the very last stage of the review.
• Amazon extended the offer several times, and the immigration application issue escalated to Canada IRCC, involving both Amazon and parliamentarians working with Vialto.
• After a year and a half since receiving the offer, unfortunately, a happy ending did not occur, and all I have left is this long journey that did not conclude as I had hoped.
• On January 4, 2023, my documents were still in the final review stage at Canada IRCC, and Amazon did not approve further offer extensions.
This marks the end of my FAANG and Canada immigration story, but unfortunately, not in my favor.

Developing microservices for pushwoosh.com in Go following clean architecture practices, configuring them with Consul, instrumenting them with Prometheus metrics, packaging them in Docker, and deploying, monitoring, and scaling them in K8S. Worked on new product development at the company, making key decisions related to the Facebook Messaging technology integrated into the new Abandoned Cart Recovery product. Developed and maintained platform solutions designed to handle 15K RPS of external traffic and 110K RPS within the cluster.

• Developed the Event Public API - a key client-facing capability, and covered it with unit and acceptance tests following TDD
• Built the MVP of a new "Abandoned Cart" product with Facebook Messenger API integration and took it to production, opening it up to customers
• Introduced SLIs/SLOs, unified global metrics, an error-budget dashboard, and alerting, then raised the success rate of problematic public APIs from ~70% to 99.9%
• Initiated and implemented Kubernetes service autoscaling driven by external Prometheus metrics, including Kafka lag
• Created a service template following clean architecture practices and rewrote the service scaffolding tool, speeding up development of new microservices
• Built a Mongo Monitor Grafana dashboard and a dedicated metrics collection package to diagnose MongoDB instability

Roles: Middle Backend Engineer L1, Middle Backend Engineer L2, Middle Backend Engineer L3, Senior Backend Engineer L1
Teams: Strategy, Abandoned cart sub-product, Customer Data Platform sub-product, Core, Production, SRE

Technologies: GoLang, gRPC, protobuf, Prometheus, Consul, Docker, K8S, PHP7(+daemons in php), PostgreSQL, MongoDB, ClickHouse, Cassandra, Kafka, RabbitMQ, Redis, Tsung, Yandex tank, Grafana, Redash, Gitlab, Microservices, REST API.

Real Estate Project Group N1.RU
API development, with ~500 RPS load, for vue.js webapp and for Android, iOS mobile applications.

• Refactored two key services, cutting the error rate across the API and background task processing by an average of 20%
• Raised unit test coverage of core functionality to 90%
• Built a test data and API mock generator, speeding up test development
• Introduced vfsStream for file system functions and reflection-based access to private methods into the team's PHPUnit testing practices
• Consistently ranked among the top 3 reviewers in peer code reviews, participating in 80% of reviews on average

Roles: Middle PHP developer
Teams: Desktop Web App API, Mobile Apps API

Technologies: PHP5.6, PHPUnit, MongoDB, Elastic Search, Redis, Swagger/OpenAPI, XDebug, RabbitMQ, Docker, Drone CI/CD, Foreman, Silex Framework, Cilex CLI Framework, Sentry, Grafana, Jira, Tsung.

Work on VipParcel and ExpressFromUS projects. Modules development, integration with post services(Aramex, DHL), ebay integration etc.

Technologies: PHP5.6, jQuery, JS, HTML, CSS, Kohana 3 framework, twitter bootstrap framework, Smarty, mercurial(Bitbucket), composer, MySQL, phpStorm, Docker, RabbitMQ.

Outsource development - CRM system, RESTfull API, ordering services, etc.

Technologies: PHP5.4, jQuery, JS, HTML, CSS, Yii2, framework, twitter bootstrap framework, swagger framework, codeception framework, git (Bitbucket, GitHub), composer, MySQL, dbForge, phpStorm, LEMP stack.

Support for the automation of business processes, companies providing energy.

Technologies: Java, SQL / Eclipse, Aqua data studio, iReport, SVN, CVS, Lotus / MS SQL Server.

Support of the business process automation system for the printing company CJSC Sitall.

Technologies: C#, Delphi, XML, SQL / MS Visual Studio, Delphi 7, SVN, SQL Navigator, Crystal Report / Oracle.

After defending the diploma project "Laboratory complex, for development and control of practical skills of working with the command interface of operating systems" was awarded a master qualification and awarded a diploma with honors.

After defending the diploma project "Development of the command interface simulator for teaching and controlling students' knowledge of the subject Operating systems. Logic of the application server" was awarded an engineer qualification and awarded a diploma with honors.