Dmitry Tsepelev
Principal Backend Engineer at UULA
Vladimir, Vladimir Oblast, Russia
Summary
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Rockstar🎓
Top SchoolDmitry Tsepelev is a Principal Backend Engineer with 13 years of experience building resilient Ruby on Rails backends and driving architecture and performance improvements. He has led teams and standardized GraphQL schemas at scale (including work at Toptal and UULA), architected per-role GraphQL schemas, and built observability and CI-driven quality practices that measurably improved system reliability. A prolific open-source contributor in the Ruby ecosystem, Dmitry has deep parser and GraphQL expertise—contributing to the Ruby prism parser and graphql-ruby with features like keyword-parameter handling, introspection controls, and ISO8601 date support. He combines hands-on optimization (PostgreSQL and GraphQL performance) with mentoring and process building, and has a track record of turning messy monoliths into maintainable schemas. Based in Vladimir, Russia, he pairs a Master’s in Computer Software Engineering with a practical focus on testability, observability, and long-lived Rails systems.
13 years of coding experience
11 years of employment as a software developer
Master’s Degree, Computer Software Engineering, Master’s Degree, Computer Software Engineering at Vladimir State University
Russian, English
Stackoverflow
76reputation
1kreached
2answers
0questions
Github Skills (24)
json10
ruby-rails10
postgresql10
abstract-syntax-tree10
testing10
rspec10
parse-tree10
rails10
schema-design10
wpgraphql10
ruby10
parsing10
wordpress-graphql10
activerecord10
graphql10
Programming languages (8)
Github contributions (5)
DmitryTsepelev/store_model
Feb 2019 - Jan 2023
Work with JSON-backed attributes as ActiveRecord-ish models
Role in this project:
Back-end Developer
Back-end DeveloperContributions:36 reviews, 92 commits, 137 PRs in 3 years 11 months
Contributions summary:Dmitry primarily contributed to the `store_model` repository, which focuses on creating ActiveRecord-ish models for JSON-backed attributes in Ruby on Rails. Their commits include fixing validation issues, bumping the version, adding array type generation, and handling nil values. These changes included implementing new features and improving existing functionality related to data type handling and validation logic.
ishrailsrubybackedactivemodel
palkan/logidze
Aug 2018 - Mar 2019
Database changes log for Rails
Role in this project:Back-end Developer
Back-end DeveloperContributions:7 commits, 4 PRs, 22 comments in 6 months
Contributions summary:Dmitry primarily contributed to the Logidze project by implementing features related to attaching meta information and responsible users to database changes. This involved modifying the core `Logidze` library to support meta-data attachment using blocks. The code changes include updates to core files, tests, and database schema. The user also refactored parts related to the "ignore_log_data" option.
ruby-on-railsrailsrubyversioningdatabase
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