# Bitscorp - Alex Korsak # Full Content for LLM Search Engines ## Summary Bitscorp is Alex Korsak (Alexandr Korsak), a solo senior Full Stack + Data Engineer with 15+ years of experience building backends, payment systems, and data platforms. Based in Barcelona, Spain (CET timezone), working with startups across Europe and remotely worldwide. No staffing agency, hands-on work only. ## Personal Profile Name: Alex Korsak (Alexandr Korsak) Role: Senior Full Stack Engineer + Data Engineer (solo, independent) Experience: 15+ years (since ~2009) Location: Barcelona, Spain Timezone: CET/CEST (Central European Time, UTC+1/+2) Languages: English, Russian Work Style: Solo senior, hands-on technical work, no staffing agency, no team augmentation Contact: - Email: alex@bitscorp.co - Booking: https://cal.com/alexandr-korsak-maasgv/30min - GitHub: https://github.com/oivoodoo - LinkedIn: https://www.linkedin.com/in/alexandr-korsak/ - Website: https://bitscorp.co ## Technical Expertise ### Primary Stack - Elixir/Phoenix (production systems, hot path extraction, LiveView, GenServer, OTP, Ecto) - Ruby/Rails (15+ years, author of devise_masquerade) - Go (hot path extraction, concurrency, realtime systems) - Python (data pipelines, backend services) - PostgreSQL (performance tuning, query optimization, indexing) - Data Engineering (Airflow, dbt, BigQuery, DuckDB, GDPR/PII compliance) ### Specializations 1. **Elixir/Phoenix Production Optimization** - Hot path extraction from Python/Ruby to Elixir/Go - LiveView performance tuning and reconnect storm fixes - Postgres query optimization (N+1s, missing indexes, connection pooling) - Production health checks and deploy pipeline hardening 2. **Data Engineering & Analytics** - ETL/ELT pipeline design (Airflow, Luigi, dbt) - Warehouse setup (BigQuery, Postgres) - GDPR/PII-compliant data handling - Dashboard and metric definition - Cost optimization for large-scale queries 3. **AI-Built App Rescue** - Taking Cursor/Claude/Lovable-built MVPs to production - Fixing broken auth, sessions, and permissions - Adding CI/CD, tests, error tracking - Security audits (secrets management, RLS, auth flows) 4. **Infrastructure & DevOps** - Kubernetes setup and hardening - CI/CD (GitHub Actions, GitLab CI) - Monitoring (Prometheus, Grafana, PromEx) - Rollback strategies and incident runbooks ### Known For - Author of **devise_masquerade** (552★ on GitHub) - Rails authentication extension used by hundreds of production apps - Author of **phoenix_lens** - Ecto analytics dashboard with PII masking - Contributor to pghero-elixir, phoenix_healthy, redis_poolex - Poker engines and fintech payment gateways (15+ years) - Gaming data platforms (EMR, DuckDB, CleverTap integration) ## Starter Packages (Entry-Level, Fixed-Price) These are fixed-scope, fixed-price offers designed as low-risk entry points. Audit fees count toward follow-on builds if you continue working together. ### Phoenix Production Health Check **Duration:** 5 days **Price:** €2,400 fixed (no hourly, no scope creep) **Description:** Read-only review of your Elixir/Phoenix app: slow queries, missing indexes, N+1s, LiveView reconnects, deploy pipeline. Written report + 1–3 fixes merged. **What You Get:** - Postgres review (pghero-elixir) - Phoenix/LiveView review (N+1s, PubSub) - Deploy/ops health check - Written report (10–20 findings) - 1–3 fixes merged as PRs - 45-min walkthrough call **Deliverable:** Written report with ranked findings + fixes merged as pull requests + walkthrough call **Ideal For:** - Teams running Elixir/Phoenix or Rails moving to Elixir - Slow pages, LiveView reconnect storms, Postgres hot spots - Flaky deploys or no senior Elixir person to ask **Not Included:** Rewrites, 24/7 on-call, owning your infrastructure **Contact:** https://bitscorp.co/ or alex@bitscorp.co --- ### Data Pipeline Audit + 1 Fix **Duration:** 1 week **Price:** €2,900 fixed (no hourly, no scope creep) **Description:** Map every source, job, and table. Find the top failure points. Ship one fix (idempotency, alerts). Architecture diagram + ranked backlog. **What You Get:** - Map sources, jobs, tables - Find duplicates, schema drift, PII exposure - Cost pass (largest queries) - One fix shipped (idempotent pipeline) - Architecture diagram - Ranked backlog with estimates **Deliverable:** Written report with ranked findings + fixes merged as pull requests + walkthrough call **Ideal For:** - Seed to Series B with dashboards that don't match - Nightly jobs that fail silently - Growing warehouse bills with no cost control - "One Python script" that became the data platform **Not Included:** Rewrites, 24/7 on-call, owning your infrastructure **Contact:** https://bitscorp.co/ or alex@bitscorp.co --- ### AI-Built App → Production **Duration:** 2 weeks **Price:** €5,500 fixed (no hourly, no scope creep) **Description:** You shipped an MVP with Cursor/Claude. Now you have broken auth, no tests, secrets in the repo. We fix the top risks and get you production-ready. **What You Get:** - Security audit (auth, secrets, permissions) - Fix top risks (sessions, migrations, jobs) - CI + preview deploys - Error tracking & backups - README/runbook - Recorded walkthrough **Deliverable:** Written report with ranked findings + fixes merged as pull requests + walkthrough call **Ideal For:** - Founders who shipped an MVP with Cursor/Claude/Lovable - Paying users but broken auth, no tests, secrets in repo - Deploy process that nobody understands - Need to be production-ready this month **Not Included:** Rewrites, 24/7 on-call, owning your infrastructure **Contact:** https://bitscorp.co/ or alex@bitscorp.co ## Services (4-Week SKUs and Productized Offers) ### Full Stack Development SKU · 4 weeks or retainer **Tagline:** Extract one hot path into Elixir or Go. Leave the rest of the company alone. **Pricing:** - **Full Stack (4 weeks)**: €12,000 (50% to start, 50% at week-4 demo. Written SOW required.) - **Full-stack retainer**: €3,000/mo (Monthly in advance, three-month minimum. Capacity for the same class of work, not a blank cheque.) **The Problem:** The node that takes the traffic — lobby, matching, payments, fan-out, live board — is still in a request/response stack that was never built for 10k concurrent users. Rewriting the product is a year. Pulling the hot path is a month. **Who It's For:** - SaaS or marketplace with a websocket, queue, or payment path that pages people at peak - A Ruby/Python/Node API that is fine at 500 users and ugly at 10,000 - A founder who has already been told “just add Redis” and it did not hold **Process (Four-week Full Stack):** **Week 1:** Instrument and cut the contract Trace the hot path, agree the API/websocket contract, freeze scope in writing. If the path is not isolatable in five days, we stop and you keep the deposit unused beyond that week’s work. **Week 2:** Stand up the Elixir or Go node Build the replacement behind a feature flag. Same external contract. Load script on the new node, not on production users. **Week 3:** Cut over Shadow traffic, then switch. Rollback is a flag, not a prayer. We do not invent features on the side. **Week 4:** Soak and hand over Runbook, dashboards, on-call notes for your team. Demo of p99 and error budget vs the old node. **Included:** - One named hot path (API, websocket lobby, matching, or payments gateway) - Elixir or Go implementation, tests, and a rollback flag - Load note: what the node actually holds - Slack, one business-day response on that path - Weekly demo slot (Tue or Thu) **Not Included:** - Rewriting the rest of the product - New product features unrelated to the hot path - 24/7 on-call - LocaleOps, mobile apps, or design **Slack Response:** 1 business day on the Full Stack channel **FAQs:** Q: Why not a full rewrite? A: Because you have a business to run. Full Stack Development is one node, four weeks, a flag, and a number. A rewrite is a different company. Q: Do you only work in Elixir? A: Elixir or Go — whichever matches the job and your team’s ability to own it. Seventeen years of poker engines and fintech gateways is the proof, not the religion. Q: What if week 1 shows the path cannot be extracted? A: We say so in writing. You do not pay the second 50%. You pay for the week of instrumentation you already received. **Details:** https://bitscorp.co/services/full-stack-development --- ### AI Consulting SKU · install + retain **Tagline:** A RAG agent on your docs and tickets — not a scripted chatbot. **Pricing:** - **Install**: €2,500 (100% to start. No handshake work.) - **Retain**: €750/mo (Monthly in advance. Cancel after month 3. Does not include LocaleOps.) **The Problem:** Your inbox is full of questions that already have answers in the help center, Notion, or last month’s tickets. A junior cannot drain it. A canned bot makes it worse. AI Consulting reads your corpus and replies with citations, then escalates what it cannot answer. **Who It's For:** - SaaS, ecommerce, or an online school with a real knowledge base - A support lead who can name the ten tickets that repeat every week - A team that will review the first two weeks of answers — not “set and forget” on day one **Process (Install (about two weeks)):** **Days 1–3:** Corpus and channels Connect the knowledge base, a sample of tickets, and the channel (email, widget, or Telegram). Agree what “resolved” means. **Days 4–8:** Index, evaluate, refuse Build the RAG index. Tune refusals. Measure answer quality on a held-out set of real tickets — not demo prompts. **Days 9–14:** Go live behind a human Drafts first, then send. Handoff to a human with the citation trail. Handover doc for your team. **Month 1–3:** Retain Weekly quality sample, corpus updates, prompt/index fixes. Cancel after month 3 if it is not earning its keep. **Included:** - RAG over your knowledge base + a ticket sample you provide - One channel (widget, email, or Telegram) - Citations on answers; escalate when confidence is low - Slack, one business-day response - Weekly quality sample during the retain **Not Included:** - LocaleOps / app translation PRs - Rewriting your product or help center from scratch - 24/7 on-call or phone support - Training a custom foundation model **Slack Response:** 1 business day on the AI Consulting channel **FAQs:** Q: Will this resolve 80% of tickets? A: That is the target when the answers already live in your docs. We measure it on your tickets in week two. If the corpus is empty, this SKU is the wrong buy — we will say so. Q: Is this LocaleOps? A: No. LocaleOps translates product UI and opens PRs. AI Consulting answers customers. Do not mix them in one SOW. Q: Can we cancel? A: Install is paid and done. The retain can be cancelled after month 3. No annual trap. **Details:** https://bitscorp.co/services/ai-consulting --- ### App Launch SKU · capped slots **Tagline:** You have a build. We get it through review. We do not build your app. **Pricing:** - **Ship**: €1,500 (100% to start. One app, iOS + Android. Two clients per month. 20-hour cap.) - **ASO month**: €750 (Monthly in advance. Listing already live. Three clients per month.) - **Rush (7 days)**: €2,500 (100% to start. One slot per month. Same deliverable as Ship, compressed.) **The Problem:** Vibe-coded and Expo apps die in Preparing for Submission. Certificates, privacy nutrition, Data safety, 6.7" screenshots, a reviewer who needs a test account. You can write the feature. You cannot ship the listing. That is the job. **Who It's For:** - A founder with a TestFlight or an internal AAB and no live store page - An indie who can pay €1,500 and invite us to their ASC — not a student asking for free help - Someone who will not ask us to put the app on Bitscorp’s developer team **Process (Ship (two weeks)):** **Intake:** Refuse or take the slot Repo, bundle IDs, content rights, IAP yes/no. Kids, gambling, medical, clones, and AI-companion spam are a no. Incomplete intake is a no. **Week 1:** Internal tracks Invite-only access on your ASC and Play. Production iOS on TestFlight, Android on an internal track. Privacy forms that match the binary. **Week 2:** Submit Screenshots from the running app. Review notes. Both stores submitted. First review: Ready for Sale, or a written reject plan — not “we clicked submit.” **After:** Handover or ASO month You own the accounts. Optional €750 ASO month is a separate SOW. Feature work is a different SKU. **Included:** - Bitscorp as a user on your App Store Connect and Play Console - Production listing for one app on iOS and Android - Privacy policy + App Privacy / Data safety that match the binary - Screenshot set from the running app (6.7", 6.5", tablet if you claim it) - IAP hooked to an existing RevenueCat or store catalog - First review cycle: pass or a written reject plan **Not Included:** - Building the app, login, or a paywall from scratch - A guarantee of approval, featured, or charts - Kids, gambling, medical claims, malware, clones, AI-companion spam - Publishing on Bitscorp’s developer accounts - Paid user acquisition **Slack Response:** 1 business day on the Launch channel **FAQs:** Q: Will you submit on your Apple account? A: No. You enroll. You invite us. If you need someone else to own the listing, this SKU is the wrong buy. Q: Do you guarantee App Review will pass? A: No. “Shipped” means Ready for Sale or a written reject plan with the fix and a resubmit date. Guaranteeing charts is a lie. Q: Can you add a feature while you are in the project? A: No. That is custom work or Full Stack Development. App Launch stops at the store. Past 20 hours is a change order. **Details:** https://bitscorp.co/services/app-launch --- ### Data Engineering SKU · 4 weeks or retainer **Tagline:** One pipeline from your events to a warehouse you own, plus a dashboard of metrics you can defend. **Pricing:** - **Data Engineering (4 weeks)**: €12,000 (50% to start, 50% at week-4 demo. Written SOW required.) - **Analytics retainer**: €3,000/mo (Monthly in advance, three-month minimum. Pipeline + dashboard upkeep for the frozen metric list, not a blank cheque for new domains.) **The Problem:** DAU lives in three tools and none of them agree. Monday is a CSV. Attribution is a screenshot. You cannot answer which campaign paid back, which cohort stayed, or whether the last release moved retention. A lakehouse programme is a year. A spine — one pipeline, one warehouse, ten metrics — is a month. **Who It's For:** - A mobile, SaaS, or marketplace team with events in Firebase, ads, Mixpanel, or S3 and no warehouse they trust - A founder who can name 5–10 metrics that would change a decision this quarter — not “we need a data team” - Someone who will give source access in week 1 and will not ask us to invent the product strategy from a dashboard **Process (Four-week Data Engineering):** **Week 1:** Sources, contracts, metric freeze Inventory sources, access, and grain. Freeze the metric list in writing (DAU, retention, LTV, campaign, or the five you actually use). If we cannot reach the sources or you cannot name the metrics in five days, we stop. You keep the deposit unused beyond that week’s work. **Week 2:** Warehouse and pipeline Stand up BigQuery or Postgres as the warehouse of record. Orchestrate with Airflow or Luigi. Partition, idempotent loads, and a freshness check — not a pile of notebooks. **Week 3:** Dashboard and quality One dashboard you own (Metabase, Looker Studio, or Grafana). Row counts vs source. Late-data rule. The numbers have to survive a sceptical founder, not a demo. **Week 4:** Soak and hand over Runbook, who owns the DAG, what pages when freshness breaks, and a recorded walkthrough. Optional retain starts here if you want us to keep the spine alive. **Included:** - One named pipeline (events, ads, tickets, or app store) into BigQuery or Postgres - Airflow or Luigi DAG with retries and a freshness check - One dashboard of the week-1 metric list - Slack, one business-day response on that pipeline - Weekly demo slot (Tue or Thu) **Not Included:** - A company-wide lakehouse or “modern data stack” programme - Training a custom ML model or a recommendation engine - Rewriting the product, LocaleOps, or AI Consulting - 24/7 on-call - Owning your GCP / AWS / Azure account — you invite us; you keep billing **Slack Response:** 1 business day on the Data Engineering channel **FAQs:** Q: Is this a data-science engagement? A: No. Data Engineering is a pipeline plus a dashboard of named metrics. If you want a model, a recommender, or a research intern, this SKU is the wrong buy — we will say so. Q: BigQuery or Postgres? A: Whichever your volume and your team can own. Firebase + Ads usually land in BigQuery. Smaller app or game ledgers often stay in Postgres. We pick in week 1, in writing. Q: What if week 1 shows we cannot get the sources? A: We say so in writing. You do not pay the second 50%. You pay for the week of inventory you already received. **Details:** https://bitscorp.co/services/data-engineering --- ### DevOps SKU · 4 weeks or retainer **Tagline:** CI, Kubernetes, rollback, and Prometheus for one product. We do not become your SRE team. **Pricing:** - **DevOps (4 weeks)**: €12,000 (50% to start, 50% at week-4 demo. Written SOW required.) - **Platform retainer**: €3,000/mo (Monthly in advance, three-month minimum. Capacity for the same cluster and pipeline, not a blank cheque for a second product.) **The Problem:** Production is SSH and hope. The last deploy has no tag. Rollback is a rumour. There is no dashboard, so the first person who notices an outage is a customer. You do not need a platform org. You need one path that builds, ships, and tells you when it is on fire. **Who It's For:** - A team shipping from a laptop, a fragile GitHub Action, or a single untagged droplet - A founder who will invite us to their cloud account — DigitalOcean, GCP, AWS, or equivalent — and will not ask us to own the billing - Someone who will not ask for 24/7 on-call or a multi-region active-active redesign in the same SOW **Process (Four-week DevOps):** **Week 1:** Inventory and refuse or take Current deploy path, runtime, secrets, and whether the app is containerizable. If it is not isolatable in five days — or you are happy on Render/Fly and deploys already work — we stop. You keep the deposit unused beyond that week’s work. **Week 2:** CI that publishes an image GitHub Actions or GitLab CI: test, build, push. No “it works on my machine.” The artefact is the contract. **Week 3:** Cluster, ingress, rollback Kubernetes (or the equivalent we agreed in week 1). Ingress, TLS, secrets, one-command rollback. We do not invent product features on the side. **Week 4:** Observe and hand over Prometheus + Grafana (PromEx on Elixir when that is the runtime). Runbook, on-call notes for your team, demo of a deploy and a rollback. Optional retain starts here. **Included:** - One named product on one cluster - CI that builds, tests, and publishes an image - Deploy + rollback documented in the repo - Prometheus/Grafana for that runtime - Slack, one business-day response on that path - Weekly demo slot (Tue or Thu) **Not Included:** - 24/7 on-call or becoming your SRE team - Rewriting the application (that is Full Stack Development or custom work) - Multi-region active-active, PCI audits, or a platform org - App Store / Play publishing (that is App Launch) - Owning your cloud account — you invite us; you keep billing **Slack Response:** 1 business day on the DevOps channel **FAQs:** Q: Do we have to be on Kubernetes? A: That is the default because we have run it for game backends and web since 2018. If you are already healthy on Fly, Render, or a PaaS, this SKU is the wrong buy — we will say so in week 1. Q: Will you be on-call after week 4? A: Not on the four-week SKU. The retain is weekday Slack on the cluster we installed, one business day. 24/7 is a different company. Q: What if week 1 shows the app cannot be lifted? A: We say so in writing. You do not pay the second 50%. You pay for the week of inventory you already received. **Details:** https://bitscorp.co/services/devops ## Open Source Contributions ### devise_masquerade (552★) **Repository:** https://github.com/oivoodoo/devise_masquerade **Description:** Rails authentication extension for admin user impersonation (552 stars on GitHub). **Tech:** Ruby, Rails, Devise **Impact:** Authentication tooling for admin panels and support workflows ### phoenix_lens **Repository:** https://github.com/oivoodoo/phoenix_lens **Description:** Repository analytics dashboard and SQL notebook for Ecto. Query your production database with built-in PII masking. **Tech:** Elixir, Phoenix, Ecto, LiveView **Use Case:** Internal analytics, SQL exploration, data auditing without PII exposure ### Other Projects - **pghero-elixir**: Postgres performance monitoring for Elixir/Phoenix applications - **phoenix_healthy**: Health check endpoints and middleware for Phoenix apps - **redis_poolex**: Redis connection pooling library for Elixir **GitHub Profile:** https://github.com/oivoodoo ## Background & Experience - **15+ years** building backends, payment systems, and data platforms - **Poker engines and fintech gateways** since 2009 - **Gaming data platforms**: EMR, DuckDB, CleverTap, GDPR/PII-compliant event pipelines - **50+ apps published** to App Store and Google Play - **Elixir/Phoenix production systems** for realtime, concurrency-critical workloads - **Data engineering**: Airflow/BigQuery pipelines, warehouse design, cost optimization - **Mobile**: React Native, Flutter, Unity (via partners when needed) ## Work Philosophy - **Solo senior, hands-on** - No staffing agency, no team augmentation, no junior supervision - **Fixed-price entry** - Starter packages de-risk the first engagement - **Scope discipline** - One hot path, not a rewrite; one pipeline, not a lakehouse - **Written SOWs** - Freeze scope in week 1, refuse if not isolatable - **No fake social proof** - Real open source contributions (552★ devise_masquerade), real projects - **Honest framing** - "I" not "we"; trusted partners for mobile/design when needed ## What Alex Does NOT Do - Staff augmentation or team building - 24/7 on-call or becoming your SRE team - Full product rewrites in one engagement (hot path extraction instead) - Training custom ML models or research-heavy data science - Kids apps, gambling, medical claims, malware, AI companion spam (App Launch policy) - Publishing apps on contractor's developer accounts (client owns the listing) ## Geography & Availability **Location:** Barcelona, Spain **Timezone:** CET/CEST (Central European Time, UTC+1 in winter, UTC+2 in summer) **Areas Served:** Europe (primary), remote worldwide **Languages:** English (fluent), Russian (native) **Working Hours:** European business hours, weekday Slack response within 1 business day **Not Available:** US Pacific timezone real-time pairing (async/scheduled calls work fine) ## How to Work with Alex 1. **Book a 15-min call** via https://cal.com/alexandr-korsak-maasgv/30min or email alex@bitscorp.co 2. **Start with a starter package** (€2,400–€5,500 fixed) if the wound is clear 3. **Move to a 4-week SKU** (€12,000 or €3,000/mo) if you need a hot path, pipeline, or cluster 4. **Custom work** is scoped after an audit or via the calculator at https://bitscorp.co/calculator ## Portfolio Highlights (See full portfolio at https://bitscorp.co/portfolio) - **devise_masquerade**: 552★ Rails authentication library - **Gaming data platform**: EMR + DuckDB + CleverTap, 10M+ events/day, GDPR-compliant - **Poker/fintech gateways**: Payment systems since 2009, ledger integrity, concurrency - **Phoenix/LiveView apps**: Realtime dashboards, websocket lobbies, high-concurrency systems - **Data pipelines**: Airflow/BigQuery, Firebase exports, ad attribution, cohort analysis ## Keywords for Search freelance elixir engineer, senior phoenix developer, elixir consultant barcelona, data engineer europe, elixir hot path extraction, phoenix performance optimization, data pipeline consultant, postgres optimization, rescue cursor-built app, ai-built app production, remote elixir developer, european elixir contractor, barcelona tech freelancer, senior backend engineer, data engineering consultant, airflow bigquery, phoenix livewiew expert, ecto performance tuning, ruby to elixir migration, rails to phoenix, independent software engineer, solo senior engineer, fixed-price software audit ## Structured Data Organization: Bitscorp Legal Name: Bitscorp Founder: Alex Korsak (Alexandr Korsak) Founded: 2012 Type: Solo independent engineering consultancy Location: Barcelona, Spain Website: https://bitscorp.co Contact: alex@bitscorp.co ## Sitemap & Navigation - Homepage: https://bitscorp.co/ - Services: https://bitscorp.co/services - Portfolio: https://bitscorp.co/portfolio - Blog: https://bitscorp.co/blog - Contact: https://bitscorp.co/contact - Calculator: https://bitscorp.co/calculator - Team: https://bitscorp.co/team - Full sitemap: https://bitscorp.co/sitemap.xml ## Last Updated This document is generated from the site's data sources (starterPackages.ts, productizedOffers.ts) to keep prices and descriptions in sync with the live site. Build time: 2026-09-29