OS-01 · ENGINEER RECORD open to work

Oleksii Sholik

Founding engineer working on distributed data systems — Postgres replication internals and BEAM/OTP performance engineering, mostly under production load.

Experience
15+ yrs backend & systems
OSS reach
20.7M+ Hex.pm downloads
Core stack
Elixir · Go · TS Python, C/C++
Based
Lucca, IT remote, EU hours
05RESUME

Blog

Mostly write-ups of things that broke in interesting ways. Everything below is in the pipeline — each entry links to a stub that will become the full write-up.

Series — Running Electric Sync in production

part 02

Deploying Electric on Fly.io

A complete walkthrough: a Fly app with an attached volume, stop-start deploys, and watching client-perceived downtime across restarts.

part 03

Deploying Electric on AWS ECS

ECS on EC2 with local disk first, then the switch to EBS — and what each choice means for deploys and durability.

part 05

Operating Electric

Config parameters, runtime metrics, logs into a collector, errors into Sentry — the operational guide.

part 06

Electric's future

Durable Streams, the Electric Circuits experiment, and a point-in-time retrospective on the architecture's strong and weak seams.

Standalone

soon

Picking up Go again

Rebuilding productivity in a language through deliberate practice — exercises, Protohackers, a toy Kubernetes operator — and why engineering judgement transfers across languages better than syntax fluency.

Projects

Open-source libraries and one language contribution, spanning 2012–present.

Porcelain2.3M+ dl

Elixir library for starting and communicating with external OS processes without the usual port-driver footguns.

github.com/alco/porcelain →
Hashids2.8M+ dl

Elixir port of Hashids — obfuscates numerical IDs as short, reversible, non-sequential strings.

github.com/alco/hashids-elixir →
Benchfella1.5M+ dl

The first micro-benchmarking tool for Elixir, predating the ecosystem's now-standard options.

github.com/alco/benchfella →
Elixir core2012–16

IEx UX (colors, history, .iex.exs), core Enum/String functions, most of mix archive.* and mix escript.*.

credited on elixir-lang.org →

Skills & work experience

Depth over breadth, mostly — the exceptions are noted where they exist. Click any skill to see where it actually shows up, in projects and past roles.

Domain depth
Languages
Infrastructure
Systems & Linux

Work experience

One line per role below; expand any of them for the resume-style detail.

Founding Engineer @ Electric Apr 2023 – present

Own the replication core of an open-source Postgres sync engine, from logical-replication internals to the production reliability that keeps it correct under real load.

Show resume bullets
  • Owned the replication path end to end — connection management, snapshot consistency, data-type correctness — and supported the service in production through observability, incident response, and infra work.Elixir/OTP · PostgreSQL · AWS ECS
  • Mitigated a production thundering-herd pattern (50K+ errors, 15× retry amplification, a 2M-message mailbox) with admission control and backpressure on overloaded processes.backpressure · admission control
  • Designed correctness safeguards between Postgres and the engine's durable logs — PITR detection, LSN/xid divergence checks, idempotent writes — and shipped restart continuity with zero missed updates.replication-slot invariants
  • Drove observability-led memory optimization using production BEAM telemetry and per-process heap attribution, bounding memory via structural sharing, hibernation, and fixed-size transaction chunking.OpenTelemetry · Honeycomb
  • Authored the team's foundational design docs: auth architecture, PG/SQLite/TS type mapping, the 1M-connection reliability roadmap, and the horizontal-scaling RFC.RFCs · design docs
Tech Lead @ Packlane Jun 2021 – Oct 2022

Consolidated infrastructure sprawled across six-plus platforms on my own initiative, and built the team's technical interview process from the ground up.

Show resume bullets
  • Audited the company's infrastructure unprompted, found services scattered across 6+ platforms, contracted two ops specialists, and directed the consolidation.AWS · GCP · Heroku
  • Cut the monthly AWS bill by ~$1,000 through service culling, EC2 right-sizing, and a planned database-disk migration.cost engineering
  • Designed and ran the technical interview loop for Mid/Senior Backend and PM roles; interviewed 20+ candidates.hiring
  • Drove the team toward a maintainable, well-tested codebase and made undocumented business logic legible via code review.Elixir · Phoenix
Senior Software Engineer @ Packlane Jul 2020 – May 2021

Reverse-engineered years of undocumented business logic into a tested, legible system, and shipped the Magento integration running on top of it.

Show resume bullets
  • Designed and built a REST API integrating Magento with the backend.Magento · REST
  • Built and maintained internal tooling for other departments, working directly with the teams that used it.internal tools
  • Reverse-engineered undocumented business rules with stakeholders, eliminated duplicate logic, and put previously vague rules under test.Elixir · Phoenix
  • Refactored the test suite to parallelize hundreds of unit tests, significantly speeding up runs.test infra
Senior Backend Engineer @ Hammer 2018 – Jul 2020

Rebuilt the core of a dealership-inventory platform in Elixir, from a custom CSV ingestion pipeline to a parallelized image pipeline feeding Facebook Marketplace.

Show resume bullets
  • Designed and built the core Elixir service at the center of the platform rewrite — import, processing, search, and export of dealership vehicle inventories.Elixir · GKE
  • Wrote a custom indexing CSV parser to fix ingestion performance on large inventory files, bounding memory while speeding up per-dealer imports.streaming parsers
  • Built a parallelized image pipeline fetching vehicle photos from dealer sites, storing them in GCS, and exporting to third-party marketplaces.GCS · Facebook Marketplace API
  • Designed the integration layer between the new service and the legacy Ruby system, enabling incremental migration.RabbitMQ
Senior Backend Engineer @ Contractbook 2017 – 2018

Shipped national-ID cryptographic contract-signing and the role-based access system that governed it.

Show resume bullets
  • Designed and implemented JWT-based cryptographic signing via Criipto, letting users sign contracts with BankID (Sweden) and NemID (Denmark).JWT · Criipto
  • Specified and built the role-based access control system, writing requirements that brought stakeholders and engineers to agreement.RBAC
  • Found that incorrect Service Worker caching left users on stale builds, and convinced leadership to disable it.frontend forensics
Backend Engineer @ PSPDFKit 2014 – 2017

Co-built real-time multiplayer PDF-annotation sync with offline support, and wrote the test suite that caught the concurrency bugs it created.

Show resume bullets
  • Co-built Instant: multiplayer real-time syncing of PDF annotations across devices, with offline editing support.Elixir · PostgreSQL
  • Built a stateful property-based test suite that surfaced concurrency bugs conventional testing had missed.QuviQ
  • Wrote "Testing HTTP APIs in Elixir," picked up by Elixir Radar and Elixir Weekly.writing
iOS Developer 2008 – 2014

Built games and their supporting developer tools from scratch at a small studio, plus freelance client work on the side.

Show resume bullets
  • Built games and supporting developer tools from scratch at a small studio.Objective-C · Cocos2D
  • Delivered features and bug fixes across client apps and games as a freelancer.C / C++ · OpenGL ES · Qt

By skill

Pick a skill to see exactly which projects and past roles used it — not just that it's on the list.

Select a skill above to see where it shows up.