NikitaBoyarkin.github.io

Personal portfolio site of Nikita Boyarkin — Product / Data Analyst. Static Astro build, bilingual (RU / EN), 17 case studies, client JS only where it earns its place.

Live: https://nikitaboyarkin.github.io/ · EN mirror: https://nikitaboyarkin.github.io/en/

Contents

• What's on the site
• Projects
• Stack
• Requirements
• Quick start
• Verification
• Project structure
• Content
• Analytics
• OG image generation
• CV
• GitHub ↔ portfolio sync
• Monitoring
• CI/CD
• Local hooks
• Documentation
• License

What's on the site

Russian is the default locale; every route below has an /en/… mirror unless noted.

Route	What it holds
/	Home — hero, headline cases, career snapshot, bento grid, featured writing
/projects/	Catalogue — all 17 cases as a board, grouped by track
/projects/<slug>/	Case study page (RU source + EN mirror)
/projects/volta/<part>/	The 23 linked sub-parts of the Volta case
/about/	About + jump nav to anchors #who, #work, #now, #start, #value
/notes/	Notes hub with category filters (absorbs /guides/)
/writing/	Paginated article archive
/topics/, /topics/<tag>/	Topic taxonomy and level grouping
/graph/	Knowledge graph of the notes — communities, force layout, zoom
/contact/	Contact
/404	RU only — no EN mirror, no hreflang

Generated endpoints: /rss.xml, /sitemap-index.xml, /robots.txt, /llms.txt, /.well-known/llms.txt, /search-index.json, /graph.json, /graph-en.json. Search is client-side over search-index.json — there is no /search/ page.

Projects

17 case studies, each with a page at /projects/<slug>/, a board column set by track, and a public repo and/or live demo where one exists. Three are the headline cases featured on the home page — volta, sql, cohort — chosen because each is backed by a reachable public artifact.

Links: page = the case study on the live site · repo = source on GitHub · demo = runnable artifact.

track: experiments

Project	What it shows	Links
Volta Neobank	Found the onboarding bottleneck and closed it with an A/B test: +5.72 pp KYC conversion, €656K/yr. 23 linked sub-projects across funnel → A/B → retention → segmentation	page · repo · demo
A/B Testing Toolkit	15 methodology modules, each calibrated by simulation — A/A holds Type I error at α, power curves plot achievable effect sizes	page · repo
Browser Mini-Games	10 playable mini-games in self-contained SVG — 7 teaching analytics (A/B to p<0.05, funnel drop-off, cohort catch, retention day), 3 arcade	page · repo · demo
Causal / Uplift	CUPED cut the standard error by 26%: same power on 5.6k users per arm instead of 10k. Uplift models recover heterogeneous treatment effects	page · repo

track: analytics

Project	What it shows	Links
SQL Analytics Case Study	26 SQL cases — 25 on a synthetic dataset (~183k events) plus 1 real-data on UCI Online Retail II: funnel, retention, LTV, attribution	page · repo · demo
RFM Segmentation	Split a bank's client base into 4 RFM segments and showed a small high-value share drives most of the revenue; marketing moved off mass campaigns	page · repo · demo
Cohort Analysis	Triangular retention and LTV cohort matrix on synthetic data: ARPU and LTV per cohort corrected for observation age, with export	page · repo · demo
Churn Prediction	Leakage-free model: recall@top-10% = 0.53, lift 3.07× at ROC-AUC 0.904 on a chronological split — no future-activity leakage	page · repo
Python Analytics Playground	Modular Python toolkit — load, clean, EDA, visualise — assembled into one pipeline with pytest coverage ≥ 80%	page · repo
Sales Calls Analytics	Streamlit dashboard over 16,891 synthetic AI-call records: 4-step funnel (greeting → offer → meeting → qualification) and loss analysis	page · repo

track: product

Project	What it shows	Links
Supabase Product Analytics	Full-stack analytics on Supabase: A/B gave +5.1 pp (p = 0.0034, chi-square); a Streamlit dashboard reads live data through Row-Level Security	page · repo
TaskFlow × PostHog	A SaaS product instrumented end-to-end with PostHog: typed event catalogue, generated traffic and 7 analyses — funnel, retention, paths	page · repo
Streamlit Dashboard	Product dashboard on a synthetic SaaS dataset (8,000 users): AARRR funnel, cohort retention, revenue — MRR, ARPU, churn	page · repo

track: engineering

Project	What it shows	Links
Reporting Automation Bot	Telegram bot replaced manual weekly reporting with cron: 1–2 hours of manual work became a scheduled report with KPI tables	page · demo
Scrolly English Speaking	Scrollytelling guide to spoken English for work conversations (A2–B1): MDX narrative with D3 visualisations	page · repo
Digital Garden	Personal Zettelkasten published as a Quartz v4 site: linked notes, backlinks and a graph instead of a chronological feed	page · repo
This Portfolio Site	The site you are reading: Astro 7, TypeScript, Markdown collections, static build, dark/light theme, RSS, sitemap, JSON-LD, Pages deploy	page · repo

Board order is set by PROJECT_ORDER in src/lib/projects.ts; featured cases by HEADLINE_PROJECTS in the same file. Every metric above is authored in the project's Markdown file and cross-checked against src/lib/metrics.ts.

Stack

Layer	Choice
Framework	Astro 7 (output: "static", no base — user Pages site served from the domain root)
Language	TypeScript 5.9 (strict), Astro components
Content	Markdown collections with Zod schemas (src/content.config.ts, Astro Content Layer)
Styling	Hand-written CSS custom properties (src/styles/global.css), 3 themes: dark (default), light, cyberpunk
Toolchain	Bun — install, scripts, tests (bun:test), lockfile
Analytics	PostHog (posthog-js), inert when the build-time key is unset; optional Plausible
Hosting	GitHub Pages via GitHub Actions
Charting	Native SVG chart components + src/lib/chart-svg.ts (no chart library)

No client framework ships: interactive bits (search, graph, theme, filters, analytics) are small vanilla modules, and posthog-js loads lazily after the first interaction.

Requirements

• Bun — the only package manager used here (bun.lock is the lockfile)
• Python 3 for make check (scripts/check_site.py)
• rsvg-convert (librsvg) — only for regenerating OG images
• Optional: GITHUB_TOKEN / GH_TOKEN for the GitHub sync scripts (higher rate limit, sees private repos)

Quick start

bun install
bun run dev          # http://localhost:4321
bun run build        # static output → dist/
bun run preview      # serve the production build

Verification

Run this triad after every content or component change. All green = safe to commit.

bun run build        # Astro build
bun run check        # astro check + tsc --noEmit on tests
make check           # astro check + tests + test:monitoring + test:built + check_site.py — validates the built dist/
bun run coverage     # same suite with coverage

make check runs bun run check (Astro/TS type-check), the test suite (test, then test:monitoring and test:built), and then inspects the built output, failing on:

• missing required pages
• internal links that do not resolve to a file in dist/
• missing images referenced from HTML
• the profile photo exceeding 500 KB
• required assets absent from index.html
• metrics drift — headline numbers in src/lib/metrics.ts vs. the site (check_metrics_drift)

Lighthouse CI runs separately — see CI/CD.

Project structure

├── astro.config.mjs        # site, i18n, redirects, sitemap
├── src/
│   ├── content.config.ts   # Zod schemas for all 6 collections
│   ├── content/            # Markdown: projects(-en), posts(-en), volta-parts(-en)
│   ├── layouts/            # Base.astro (nav, theme, meta, PostHog), Post.astro
│   ├── components/         # 27 components + 7 chart primitives — cards, filters, graph, hero
│   ├── lib/                # pure logic: metrics, topics, graph, fuzzy, charts, brand, path
│   ├── pages/              # 24 routes + endpoints (rss, sitemap, robots, llms.txt, search-index.json)
│   ├── data/               # chart data + generated github-activity.json
│   └── styles/             # global.css (tokens + themes), blog.css
├── scripts/                # OG/CV generators, GitHub sync, check_site.py, content-drift-audit, mobile audits
├── tests/lib/              # 25 bun:test suites for src/lib/*
├── docs/                   # PRDs, ADRs, SPEC, analytics review ritual
├── monitoring/             # local RED monitoring stack (Prometheus + Grafana)
└── public/                 # images, hero SVGs, OG images, fonts, CV PDF, demos, games

src/lib/ holds all non-trivial logic and is the only part covered by unit tests. Components stay presentational.

Key src/lib modules

Module	Responsibility
metrics.ts	Single source of truth for headline numbers (hero, career snapshot, value page, CV cross-check)
projects.ts	PROJECT_ORDER, project loading, sorting
topics.ts	TOPICS taxonomy + level grouping — drives /topics/
posts.ts	Post loading, PER_PAGE pagination
graph.ts / graph-layout.ts / graph-data.ts / graph-tooltip.ts / graph-zoom.ts / graph-url.ts	Build-time knowledge graph: greedy-modularity communities, force layout, interaction
charts.ts / chart-svg.ts	Chart config and the SVG primitives the chart components render
fuzzy.ts	Dependency-free Levenshtein ≤ 2 for search (Cyrillic-safe)
analytics.ts / beacon.ts / scroll-depth.ts	Client analytics: typed track(), RED beacon, read-depth
brand.ts	Palette tokens + WCAG contrast assertion (shared with the OG renderer)
path.ts	withBase() — use it for every internal link and asset path
llms-txt.ts	Build-time llms.txt generator, shared by /llms.txt and /.well-known/llms.txt so the two cannot drift
qa-corpus.ts	Curated bilingual Q&A corpus behind the "Ask me" widget (AskMe.astro)

Content

Six collections, schemas in src/content.config.ts:

Collection	Files	Language
projects	17	RU
projects-en	17	EN
volta-parts	23	RU
volta-parts-en	23	EN
posts	24	RU
posts-en	2	EN

Add a project

1. Create src/content/projects/<id>.md and src/content/projects-en/<id>.md — always both.
2. Add a hero SVG to public/images/ (the hero field is required).
3. Set track (experiments | analytics | product | engineering) for the kanban board.
4. Add the slug to PROJECT_ORDER in src/lib/projects.ts.
5. bun run build && make check.
6. bun run sync:gh:apply to set updated: from the repo's last push.

Add a blog post

Create src/content/posts/<slug>.md. category must be one of decision-log, framework, guide, note — a local hook (portfolio-category-guard.js) blocks anything else. Add an EN mirror in posts-en/ when it should be bilingual.

Authoring rules

• Project page skeleton — STAR (H2 order): Ситуация → Задача → Действия → Результат → Ограничения → Документация. EN: Situation → Task → Actions → Result → Limitations → Documentation. Action should be the longest section (50–60% of the body); Задача is 1–2 sentences of first-person goal and carries no digits. Volta parts add Рекомендации / Recommendations; the volta hub keeps its own D10 narrative. Bound by tests/lib/content-skeleton.test.ts.
• Descriptions: 1–2 sentences, result + number first, 120–200 chars; the first 72 chars must stand alone (MaterialStrip truncates there). Author RU and EN independently — meaning parity, not literal translation.
• Numbers are frozen. A readability rewrite never changes a metric. bun run audit:content diffs every numeric token in src/content/** against docs/content-baseline.json and exits 1 on any change. Accept an intentional change with bun run audit:content:snapshot.
• related: is locale-neutral — write /projects/<slug>/ and /posts/<slug>/ in both languages; the EN resolver prefixes en/ itself. Never write /en/projects/....
• Volta hub map is generated. The grouped map in projects/volta.md between <!-- volta-map:start -->/<!-- volta-map:end --> comes from bun run volta:map. Re-run after adding or renaming a part.
• Fold one-off sections (Architecture, Run, Testing, …) under Действия / Actions.

Bilingual routing

• RU is the default locale; EN mirrors live in src/pages/en/ and render the -en collections.
• Every Base page passes lang and counterpartHref; LangSwitch.astro toggles and emits <link rel="alternate" hreflang>.
• When adding a page, ship both languages and wire counterpartHref on both sides.
• RU-only on purpose — no EN mirror, no hreflang: notes, 404.

Redirects

Old routes collapse into the /about anchor cluster (astro.config.mjs): /whois/, /work-with-me/, /now/, /start/ → /about/#… (with /en/ twins for the first three); /guides/ → /notes/guides/; /cv/ → the CV PDF.

Analytics

src/components/Analytics.astro renders the PostHog snippet. It is inert unless the build-time env vars are set — all of them are PUBLIC_*, so they bake into the static build:

Variable	Purpose
PUBLIC_POSTHOG_KEY	Project token — no snippet rendered when unset
PUBLIC_POSTHOG_HOST	Defaults to https://us.i.posthog.com
PUBLIC_PLAUSIBLE_DOMAIN	Optional — Plausible script, for a privacy-friendly counter
PUBLIC_PLAUSIBLE_SRC	Optional — custom or self-hosted Plausible script URL
PUBLIC_BEACON_ENDPOINT	Optional — pushes scroll-depth / RED beacon events to the monitoring stack (BeaconMetrics.astro)

Copy .env.example to .env for local development; for CI the same names go into GitHub Actions secrets.

src/lib/analytics.ts is the only client module that talks to PostHog besides Analytics.astro (which owns init). Components call track(); they never touch the global. posthog-js is lazy-loaded after the first user interaction, so consumer chunks stay off the critical path, and track() buffers (bounded, flushed on attach) rather than dropping early events.

Typed events (AnalyticsEventMap): project_viewed, post_read, lang_switched, theme_change, ask_me_used, random_post_click, section_viewed, outbound_click, search_used, search_no_results, read_depth, filter_applied, projects_track_filter. Super properties: locale, theme, prefers_reduced_motion, initial_referrer_class, landing_path — the first-touch class is computed once per visitor and persisted.

Convention: any element carrying data-analytics="<name>" fires <name> on click through a delegated listener in Analytics.astro (featured_project, cv_download_pdf, bento_*, headline_all_projects, …). New CTAs should reuse that attribute instead of calling track() for the same click — mix the two and a click is counted twice.

OG image generation

bun run og         # per-post OG cards (24 PNG + webp)
bun run og:home    # homepage identity banner
bun run og:graph   # knowledge-graph preview
bun run og:cv      # CV OG / LinkedIn / cover variants (og:cv:li, og:cv:cover)
bun run og:watch   # regenerate on change

Rendering goes through rsvg-convert with vendored fonts in scripts/og-fonts/. scripts/lib/og-render.mjs sets both FONTCONFIG_FILE and PANGOCAIRO_BACKEND=fc — macOS defaults to the CoreText backend, which ignores fontconfig and silently renders the wrong font. Every generated banner passes a WCAG AA contrast assertion before it is written. Palette lives in src/lib/brand.ts, shared with global.css. scripts/audit-palette-coverage.mjs reports where palette tokens are used (it has no npm script — run it directly with bun).

CV

The CV is not authored here. It lives in a separate rendercv project at ../cv/ (Boyarkin_Nikita_Product_Analyst_CV.yaml). The portfolio ships one downloadable PDF, public/CV-Nikita-Boyarkin.pdf, behind a single "CV" button on every page.

# in ../cv/
rendercv render Boyarkin_Nikita_Product_Analyst_CV.yaml
# here
bun run cv:pdf     # copies into public/ — override the source dir with CV_SOURCE_DIR

Headline numbers must agree with src/lib/metrics.ts. Commit the PDF; do not reintroduce a hand-authored /cv/ page.

GitHub ↔ portfolio sync

scripts/sync-github-projects.mjs keeps updated: and private: frontmatter in sync with the GitHub API for every repo referenced by github: (RU + EN twins). It never touches date:, which is the authored publication date.

bun run sync:gh              # check mode — reports drift, exit 1 on hard drift (runs in CI)
bun run sync:gh:apply        # write updated:/private: back into frontmatter
bun run sync:gh --dry-run    # preview
bun run sync:gh:candidates   # public, non-fork repos not yet featured

scripts/sync-github-activity.mjs writes src/data/github-activity.json (contributions, streaks, 5 chart cards) for the /about charts. Auth via GITHUB_TOKEN / GH_TOKEN / STREAK_PAT. Both run on schedules — see CI/CD.

Monitoring

monitoring/ holds a self-contained RED stack (Rate / Errors / Duration): a Bun exporter with Prometheus exposition + embedded SQLite, Prometheus, Grafana and a Cloudflare tunnel. Runs locally via Docker. See monitoring/README.md — it needs a PostHog personal API key, not the public project token.

CI/CD

Three workflows in .github/workflows/:

Workflow	Trigger	Does
deploy.yml	push / PR to master | main	install → GitHub drift gate (sync:gh, exits 1) → bun run check → bun run test → build → make check (tests + test:monitoring + test:built + check_site.py) → Lighthouse CI → deploy dist/ to Pages
sync-github.yml	weekly	runs sync:gh:apply and opens a PR with the changes
github-activity.yml	daily	refreshes github-activity.json; commits only when the payload changed

Pull requests run every gate except deploy. Lighthouse runs in a separate job with no analytics env vars, so the scores stay clean.

Lighthouse assertions (.lighthouserc.json, 7 URLs): accessibility, best-practices and SEO are errors at ≥ 0.95; performance is a warning at ≥ 0.85.

Do not push to master before confirming Pages is set to Settings → Pages → Build and deployment → GitHub Actions.

Local hooks

.claude/hooks/ — contrast-gate.js (colour-contrast gate on generated output) and portfolio-category-guard.js (blocks post frontmatter with an out-of-taxonomy category).

bun run verify:writing-filter is a Playwright regression check for the /writing/ filter. It runs against a served build (bun run serve-dist first, or point BASE_URL anywhere) and guards the CSS-cascade bug fixed in src/styles/blog.css, where an author display beat the UA [hidden] { display: none } rule and the list stayed visible after a filter click.

Documentation

Path	Contents
CLAUDE.md	Full repository guide — schemas, conventions, command reference
CONTEXT.md	Domain glossary for the conversion surface (RU)
docs/prd-v8.md	Current PRD (RU) — replaces prd-v7.md
docs/cta-inventory.md	Every CTA, its event and destination
docs/analytics-events.md	Event catalogue with payloads
docs/analytics-review.md	Weekly 15-minute analytics ritual + funnel benchmark
docs/contact-log.md	Manual hiring funnel log
docs/backlog.md	Open work
docs/adr/	Architecture decision records
DESIGN.md	Visual system notes

Older PRDs (prd-v2 … prd-v7) are kept for history. Prefer docs/prd-v8.md and CLAUDE.md when they disagree.

License

See LICENSE.txt. Site content and copy are personal — please don't reuse the text or profile assets.