I’m Sergey
Software Engineer
I build the parts of a product that talk to something else: web services and APIs, LLM integrations, bots, and the automation between systems. Python and FastAPI, Node.js, PostgreSQL and Docker, Gemini/Claude with RAG and function calling, n8n, CRM and REST APIs — plus native Android in Kotlin.
What I do: web services and APIs (Python/FastAPI, Node.js, PostgreSQL, Docker), AI in products (Gemini API, streaming, function calling, RAG), automation and integrations between services (n8n, CRM, REST APIs, webhooks), API reverse engineering. From parsers and bots through to shipped production apps.
Right now: DeepBrief — AI summarisation of video and audio through a streaming Gemini API pipeline, and TrackerScout, a product live on the Chrome Web Store with a serverless Cloudflare Worker + D1 backend behind it: licensing, device slots and billing, with the Pro token verified on the device.
Selected projects: TrackerScout (Chrome Web Store) · AliExpress · DeepBrief · Aligram (500K+ installs) · ArtstationFollow · CASHOFF · Fast Timer
Read more Collapse about · web · AI · integrations
# about
12+ years in development. I started on the web (LAMP, PHP), spent years on parsers and automation in C#, moved through data work in Python and native Android in Kotlin, and now build web services and LLM integrations on a serverless and containerised backend, with RAG and the automation around them.
I design systems to stay readable (Clean Architecture, SOLID) and keep the logic under unit tests — including in JavaScript, where the pure parts of an extension run offline against captured page fixtures. The work I enjoy sits at the seams: function calling and RAG, API reverse engineering, and low-level network behaviour.
# web services and backend
- Services and APIs: Python (FastAPI) and Node.js, REST and webhooks, async workers and background queues
- Data: PostgreSQL including pgvector for RAG, SQL, schema migrations, ETL pipelines
- Delivery: Docker, Git / GitHub, and serverless on Cloudflare Workers + D1 where it fits — licensing, billing callbacks, edge endpoints
- Practice: Clean Architecture and SOLID on the backend too, business logic under unit tests, browser extensions on Manifest V3 with the same serverless backend
- The older foundation, still load-bearing: PHP (CodeIgniter), MySQL, JavaScript — a CPA network with real-time tracking and billing, WordPress marketplaces with custom plugins, CMS customisation at code level (Drupal, Joomla, DLE)
# AI integrations and tooling
In production: Gemini API (google-genai SDK) with streaming and function calling, plus RAG pipelines. AI is also a daily tool in the code itself — Claude Code, Cursor, Antigravity, Opencode across Claude, Gemini, Kimi and GLM models, which shortens the feature loop considerably.
Everything that lands goes through my own code review and an architecture check. I maintain a technical documentation system (Memory Bank) and write custom AI skills and MCP configurations for agent workflows. Screens get prototyped through Google Stitch and NanoBanana, with assets in Figma.
# automation and reverse engineering
- Automation cores and parsers in C# (.NET, ZennoPoster API, HtmlAgilityPack); data collection over APIs, regex and XPath
- Reverse engineering of private APIs (ArtStation Graph/REST, YouTube InnerTube)
- Working through protections: Cloudflare 403 / WAF, PoToken / BotGuard, fingerprint rotation, Anti-Captcha
- ETL pipelines and end-to-end analytics in Python / SQL — fraud detection, dashboards in Looker Studio
# Android development
- Languages: Kotlin (2.2), Java
- UI: Jetpack Compose, Material Design 3, NavigationSuiteScaffold, custom components, themes (System/Light/Dark/OLED)
- Architecture: Clean Architecture, MVVM, MVP, SOLID, multi-module
- Async: Coroutines, Flow, WorkManager, foreground services
- Data: Room, DataStore, Retrofit / OkHttp, kotlinx.serialization, JSON
- DI / build: Hilt, KSP2, AGP 9.x, Gradle
# tools and environment
- Android Studio, Git / Git Flow, GitHub, Bitbucket, Firebase, Wrangler, Docker
- Daily driver is Arch Linux (CachyOS): Niri WM + Noctalia Shell, Alacritty + Fish, micro as the editor. I tune the system myself, write shell scripts for the recurring work, and am comfortable in the low-level Linux plumbing
- Solid understanding of networking, client-server behaviour and performance work — at application level and at system level
- Obsidian as a personal knowledge base: linked notes, plugins, templates
# skills
# what I do
Web development
Services and APIs end to end: Python (FastAPI) and Node.js, PostgreSQL, REST and webhooks, background workers and queues, Docker. Shipped as containers or serverless on Cloudflare Workers + D1.
Automation and integrations
Services wired to each other: CRM and REST APIs, webhooks, scenario orchestration in n8n. Bots and parsers in Python and C#, plus API reverse engineering when there is no documented way in.
AI integrations (LLM in products)
LLM features that ship: Gemini API with streaming, RAG pipelines, function calling, content processing. Claude Code and AI agents as part of the daily development loop.
Android apps
Kotlin, Jetpack Compose, Clean Architecture + MVVM. From architecture and unit tests through performance work to a release on Google Play.
# experience
Software Engineer · Chrome MV3, Cloudflare Workers
TrackerScout — browser extension (Chrome Web Store)
- Manifest V3 extension published on the Chrome Web Store in English and Russian: read/unread tracking, topic filters and hiding, full-size previews, ad-layer and click-hijack cleanup
- Per-domain optional permissions with content scripts registered and unregistered live — the extension ships with no site list and no page access until a user grants one
- Cloudflare Worker + D1 backend: licensing, device slots with a rotation budget, billing callbacks; Pro tokens signed with Ed25519 and verified offline with a 7-day grace
- Pure modules kept free of DOM and Chrome APIs so parsing, settings migrations and panel geometry run in an offline test suite against captured page fixtures for four engines
Full-stack Developer · AI assistant, Cloudflare Workers
The Other Side Movers — moving company, Denver, US
- Rebuilt the site of a Denver moving company around the three answers the old one never gave — a question answered, a price seen, a service area checked — on plain HTML and Tailwind over Cloudflare Pages, with no CMS and no monthly platform fee
- AI concierge on a Cloudflare Worker + Workers AI (Llama 3.1): SSE streaming, a knowledge base generated from the client’s own material and served from KV, output guards that strip invented prices and prompt leakage
- Instant estimate from two addresses — Nominatim autocomplete and real OSRM driving distance, with stairs, piano, packing and storage as modifiers; the result rolls into a pre-filled request form, so the visitor becomes a lead on the same screen
- Python data stage behind it: a stealth-browser crawl of the old site and the review platforms (13 pages, 146 reviews, 27 photos) into one site.json contract that the page, the assistant and an automated acceptance check all read
AI Developer · Gemini API, streaming, Clean Architecture
DeepBrief — AI powered content core
- Android app summarising YouTube and audio against user prompts; Gemini API (google-genai) streamed through channelFlow with model fallback 3.5→2.5 Flash and truncation detection
- Single-pass audio processing (Gemini Files API) — one request instead of two, ~2x fewer input tokens; built-in chat with strict role alternation and atomic writes
- Clean Architecture + MVVM, ~10.6k lines of Kotlin, 8 ViewModels, UI/Domain/Data separated; unit tests on parsers, use cases and chat roles
- Subtitle pipeline with no external dependencies: reverse-engineered InnerTube API (visitorData/cpn), HTML-scraping fallback, TTML/XML parsing, PoToken/BotGuard handled on Android 15
AI & Automation Developer · LLM, RAG, n8n, CRM
Amazonica — E-commerce brand
- LLM assistant for e-commerce on Telegram (aiogram 3) and VK — one dialogue core across both channels
- Gemini API with streaming and function calling: catalogue search, order creation and status; RAG over the product base (embeddings + pgvector)
- Bots, sales funnels across three channels and CRM integrations; scenario orchestration and operator escalation through n8n; FastAPI webhooks, PostgreSQL, Docker
- ~70% of requests auto-answered, support workload −65%, conversion to order +18%; card A/B tests → conversion up to +120%, orders up 2–3x
Android Developer · Kotlin, Clean Architecture
Fast Timer — Startup
- Timer app with 99.9% firing accuracy across Android versions including MIUI / HyperOS (WorkManager, foreground services)
- Battery consumption cut by 80%, cold start under 1.5s
- Custom UI components (circular progress, wheel picker, MD3) and a notification system on AlarmManager with haptics
- Feature work ~240% faster with AI tooling (Cursor, Antigravity); screens prototyped through Google Stitch / NanoBanana + Figma
Automation Engineer · C#, API integrations
ArtstationFollow — Automation Service
- Automation core in C# with reverse-engineered ArtStation APIs (Graph/REST), Cloudflare 403/WAF handling, fingerprint rotation, Anti-Captcha
- Services marketplace on WordPress/PHP with custom plugins bridging it to the C# backend
- Technical SEO (Schema.org, Core Web Vitals) → #1 in Google for “artstation promotion”
- 90+ orders a month at ~15% conversion, fully automated
Android Developer · Java
Aligram — E-commerce Aggregator
- E-commerce aggregator app with 500,000+ installs
- Resilient network layer for the high-load AliExpress affiliate API, nested JSON parsing into native models
- Global search with filters, Room-backed offline favourites, paginated RecyclerView listings
- Localisation into 8 languages, AdMob native ads placed without hurting retention
Marketing Automation Engineer · Python, SQL, API integrations
AliExpress — Alibaba Group joint venture
- End-to-end analytics (Google Ads / Facebook / MyTarget / Yandex / DSP) merged into one dashboard
- Automated report parsing through the Marketing APIs → −90% time spent on reporting
- SQL fraud detection — blocked fraudulent suppliers, saving 2% of the marketing budget
- Google Ads CR +12%, Facebook +17%; A/B testing for ASO → install rate +6–9%
Automation Engineer · C#, CRM integrations
CASHOFF — fintech solutions for banks and brands
- C# toolkit automating LinkedIn lead generation → −80% manual work for the sales team
- Behaviour-aware following and account warm-up algorithms
- Maintained the corporate web properties and wired landing pages into the CRM over REST
Full Stack Web Developer · PHP (CodeIgniter)
OverAds — CPA Advertising Network
- Designed a CPA network from scratch on CodeIgniter, with publisher and advertiser dashboards
- Real-time tracking (clicks / impressions / conversions), SQL tuned for large tables
- Ad server with fraud protection, billing through payment provider APIs, ticket system
Android Developer · Java, ExoPlayer
Funnygram — Entertainment App
- Infinite video feed on RecyclerView with a custom LayoutManager
- Pre-fetching logic and ExoPlayer loops with explicit memory management
- Glide cover cache → 60 FPS, H.264 compression, GIF/MP4/WebP support
Software Developer · C#, data extraction
Self Dev — Freelance
- Multithreaded C# parsers (HtmlAgilityPack) collecting data from open sources
- ETL pipelines: parse → clean (regex) → publish to WordPress over XML-RPC
- Auto-bidding through the Yandex Direct API, low-level HTTP work on sockets
Full Stack Web Developer · LAMP
HENZO.ORG — Web Development Agency
- Full-cycle development on the LAMP stack (Linux, Apache, MySQL, PHP)
- CMS customisation at code level (Drupal, WordPress, Joomla, DLE) for search requirements
- Ran a network of 50+ sites: administration, DNS, MySQL tuning
# what colleagues say
“Sergey writes code, gets things shipped, and is easy to work with. Forget the job hunt — let’s go build something of our own together :)”
“I worked with Sergey at ECPI Media — he knows his craft and can handle volume. If he takes something on, it will be fine.”
“Strong with data and with systems that are not meant to be easy to work with — he digs until it works. Level-headed, and good company.”
“I worked with Sergey — he understands the technical side and takes a thing all the way through to a working result.”
“Thank you for your patience and understanding. You are a very strong colleague — I hope you find the path where your success is beyond doubt. You put in the work and it will pay off. My door is always open if you need anything.”
# education
Higher education
Moscow University of Industry and Finance
Vocational college
Moscow College of Finance and Credit