Nikita Andreiev

Nikita Andreiev

Software engineer and security researcher in Saarbrücken, working on AI code evaluation, web apps, and chess tools.

Email me See the work

Paris, 1858

Paul Morphy plays the Duke of Brunswick and Count Isouard, together, in a box at the opera.

Scroll to play the game. My chess analyzer reviews games like this one, move by move, in your browser.

Skip the game
Based in
Saarbrücken, Germany
From
Kyiv, Ukraine
Speaks
Ukrainian, Russian, English, German

I spend most days trying to prove code wrong. I write engineering tasks whose hidden tests pass a correct solution and fail a plausible wrong one, review AI-generated code for the bugs it hides, and test web apps for broken access control. In between I build the things I want to exist: a chess analyzer that runs Stockfish in your browser, and a platformer about a rope.

Works with

  • Java, Spring BootBackend
  • PythonServices, tooling
  • TypeScript, JavaScriptBrowser
  • SQL, PostgreSQLData
  • WebAssembly, Web WorkersEngines
  • Docker, LinuxSandboxes
  • JUnit, pytestTests
  • REST, GraphQLAPIs
  • Git, GitHubEverything
  • Claude Code, CodexDaily

Chess Analyzer

A full Stockfish 18 game review that runs entirely in your browser through WebAssembly. Import a game from Chess.com or Lichess and every move gets classified, from brilliant to blunder, with accuracy by phase and live engine lines. Nothing leaves your device.

JavaScript, WebAssembly, Web Workers. Share links are 63% shorter thanks to gzip.

Open the analyzer Source
Chess Analyzer reviewing a game: the board on a brilliant bishop sacrifice, both accuracy scores, the classified move list and the engine's top lines.
Chess Analyzer's evaluation graph over a whole game next to accuracy by opening, middlegame and endgame for both players.

p3n.si

p3n checks whether a text was written by AI and helps you rewrite it: four open-source writing skills and a pay-as-you-go API. I redesigned its landing page with one typeface, a shorter hero with the tool right beside it, plainer sections and plainer copy.

UI and copy redesign. Free to try, no account needed.

Try p3n.si Install p3n
p3n.si after the redesign: a short sans-serif headline, Find the AI in any text, with Try it free and Self-host from GitHub buttons, next to the AI detection tool.
p3n.si before: a three-line serif headline and a list of four arrow points, next to the same AI detection tool.

p3n for Chrome

p3n's browser extension, now in the Chrome Web Store. Select text on any page, right-click, and see whether it reads as AI-written and which sentences give it away. Rewrite drops the filler, and Replace puts the new version where your text was. It runs in Edge and Brave too.

Firefox and Google Docs versions are in store review; Word and Excel install from the all-apps page for now.

JavaScript, Manifest V3, a side panel. Your text leaves the browser only when you click.

Add to Chrome All apps Source
p3n's side panel in Chrome next to a blog post with a paragraph selected: Likely AI-written, 94%, with the two sentences that read as AI.
TETHER, level one: the hooded player swings on a rope from a grapple ring over a spike pit, coins ahead and the next ring locked on, with hearts, timer, S-rank target and dash meter in the corner.

TETHER

A grapple-swing precision platformer in a single HTML file. Five verbs (swing, release, dash, attack, steer) and nineteen hand-tuned levels across three worlds, each with a boss. Ghost replays, a level editor with JSON import and export, and a pipeline that checks every level can be finished.

Play the demo Source
TETHER’s level select for World 3, The Inferno: seven level cards with minimaps, plus skins, secrets, settings and the control keys.

Also: a Python video compressor that shrinks any clip to a target file size with FFmpeg, and a Telegram bot that talks to a language model.

Hire me to

Now
AI code evaluator and task authorSelf-employedHidden-test tasks, 10+ languages2026–
Security researcherIndependentWeb applications2026–
Before
Senior software engineerGoogleDiagnostic services, incidents2025–2026
Software engineerOracleDatabase tooling, test automation2023–2024
Software engineerGlobalLogicSpring Boot services, PostgreSQL2021–2023
Study
B.Sc. Business InformaticsSaarland UniversitySaarbrücken2026–
B.Sc. TelecommunicationsIgor Sikorsky KPIKyiv2023–2025

Security, evaluation or backend work? Write to me.

Saarbrücken, Germany. Open to remote.

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