John Polis

Backend • Middle

Java

Active 1 day ago

Invite to interview

Message

Download CVCV

Overview

Technical skills

Roles

Overview

A Middle-level Java developer focused on algorithmic implementations and classical cryptography with clear, test-driven code. The strongest proven skill is implementing and testing classical cipher algorithms and linear-algebra routines as shown in Security/HillCipher.java and MonoalphabeticCipherTest.java. The public code does not demonstrate production backend concerns such as REST APIs, databases, deployment, or auth flows.

Technical skills

Java• Middle • 3y+

Frontend

Next.js

React.js

Tailwind CSS

Middle Backend Developer Confidence: High Generalist

API Design

How well APIs are designed

Not evidenced in public code

Data Layer & Database

Working with databases

Not evidenced in public code

Scalability & Performance

Handling load and speed

Not evidenced in public code

System Architecture

2/10

Overall system structure

Modular class organization and small domain modelling are present, but no non-trivial service decomposition or operational architecture.

Evidence

John19110/Radar-System/Radar.java: Rule interface and Radar class applying rules over Observations John19110/security/src/main/java/security/PlayfairCipher.java: encapsulated PlayfairCipher class with generateKeyMatrix and prepareText helpers

Security & Auth

3/10

Protecting data and access

Algorithmic security work is demonstrated (classical ciphers and careful input preparation) but no production auth/authz, token lifecycle, or secrets management.

Evidence

John19110/security/src/main/java/security/HillCipher.java: modularInverse, determinant and matrix inversion logic John19110/security/src/main/java/security/PlayfairCipher.java: prepareText sanitization replacing J with I and validation

Reliability & Observability

3/10

Stability and monitoring

Good unit test coverage for algorithm correctness and some custom exception handling, but limited operational reliability patterns (timeouts, retries, structured logging).

Evidence

John19110/security/src/test/java/MonoalphabeticCipherTest.java: large frequency-analysis unit test John19110/security/src/test/java/ColumnarCipherTest.java: comprehensive unit tests for encryption/decryption and analysis

Expertise

Java• Middle

Industries

Cybersecurity• Middle

Technologies

Java• Middle • 3y+

Recommendations

Develop small, well-tested Java libraries for algorithmic utilities and classical cryptography where correctness is critical.
Implement end-to-end examples that expose these algorithms via a simple, well-documented API to demonstrate production boundary decisions (validation, error contracts, idempotency).
Expand reliability and operational skills by adding structured logging, timeouts, and CI-driven test matrices to simulate larger inputs and edge cases.
Contribute cipher implementations to a larger security-focused project to gain experience integrating with secrets management and security reviews.

Repositories

The developer's experience in this domain has been verified based on AI analysis of the following repositories:

John19110 Radar-System security

Middle Frontend Developer Confidence: Medium UI Engineer

Frontend UI Engineer (3+ yrs exp) focused on polished, motion-rich product frontends for consumer mobile/web experiences. The strongest proven skill is building reusable, presentation-layer components with deliberate composition and motion integration, exemplified by the Reveal, GlowCard, SectionHeader and Hero components in John19110/safetraq/_next/static/chunks/04m-uftv9lehb.js. There is limited public evidence of server-state architecture, automated tests, or non-trivial async state management and the codebase relies heavily on established libraries for complex animation and interaction behavior.

UI Component Architecture

6/10

How interface parts are built

Reusable, composition-first UI components and small design primitives (Reveal, GlowCard, SectionHeader, MagneticButton) show deliberate component boundaries and reuse, but much of the complex animation/interaction behavior is delegated to a third-party motion library rather than custom architecture.

Evidence

John19110/safetraq/_next/static/chunks/04m-uftv9lehb.js: function Reveal (Reveal component) John19110/safetraq/_next/static/chunks/04m-uftv9lehb.js: function GlowCard (GlowCard component) John19110/safetraq/_next/static/chunks/04m-uftv9lehb.js: function SectionHeader (SectionHeader component)

Responsive & Cross-browser

4/10

Works on all screens and browsers

Responsive UI built with utility classes (Tailwind) and Next.js Image/layout patterns; typical breakpoint-driven responsiveness is present but there is no evidence of advanced responsive techniques like container queries or explicit RTL/i18n plumbing.

Evidence

John19110/safetraq/_next/static/chunks/04m-uftv9lehb.js: Hero and layout use Tailwind breakpoint classes (e.g. 'sm:text-4xl lg:text-5xl', 'grid sm:grid-cols-2') John19110/safetraq/_next/static/chunks/04m-uftv9lehb.js: Demo and Team pages use next/image with width/height and responsive classes

Performance Optimization

3/10

Speed of the interface

Some performance-minded choices (lazy iframe loading, optimized image usage, motion/appear optimizations) and use of a performant animation library, but there is little visible bespoke measurement, before/after metrics, bundle-analysis artifacts, or custom virtualization.

Evidence

John19110/safetraq/_next/static/chunks/04m-uftv9lehb.js: YouTubeEmbed uses iframe with loading:'lazy' and title attribute John19110/safetraq/_next/static/chunks/04m-uftv9lehb.js: Hero component uses motion animations and a floating optimized image (Next.js Image usage)

Accessibility & Semantics

5/10

Usable for everyone

Reasonable accessibility and semantics: labeled form controls, explicit button types, and iframe titles; some ARIA/focus handling is provided by motion/utility code (framer-motion), but there is not a clear, auditable a11y test/CI pipeline visible in the provided artifacts.

Evidence

John19110/safetraq/_next/static/chunks/04m-uftv9lehb.js: Contact form has <label htmlFor> and input id/name attributes and required:true John19110/safetraq/_next/static/chunks/04m-uftv9lehb.js: YouTubeEmbed iframe includes title and allowFullScreen; images include alt attributes

State Management & Data Flow

2/10

Managing data in the app

State is predominantly local component state and animation-driven (useState/useRef) with minimal server-state discipline; no evidence of request cancellation, optimistic updates, cache invalidation, or state machines implemented by the developer.

Evidence

John19110/safetraq/_next/static/chunks/04m-uftv9lehb.js: Contact component uses local useState for submit feedback and onSubmit builds a mailto link John19110/safetraq/_next/static/chunks/04m-uftv9lehb.js: AnimatedCounter uses a motion-driven value/ref pattern (local state + animated spring)

UX & Visual Polish

6/10

Look and feel quality

High visual polish and UX attention: motion-led reveals, hover/interactive micro‑interactions (MagneticButton), floating screenshot composition, and consistent design tokens/utility classes. Loading and perceived-performance choices (lazy embeds, skeleton-like reveal animations) are used to improve perceived UX.

Evidence

John19110/safetraq/_next/static/chunks/04m-uftv9lehb.js: Hero component with animated headline, floating phone mock, and reveal animations John19110/safetraq/_next/static/chunks/04m-uftv9lehb.js: MagneticButton and Reveal used across pages to provide micro interactions and entrance animations

Expertise

React• Middle

Modern Web Frameworks• Middle

Industries

Transportation & Logistics• Middle

Technologies

Tailwind CSS

Next.js

React.js

Recommendations

Design and build marketing/product frontends and component libraries where motion and brand polish matter (landing pages, app microsites).
Lead implementation of interactive prototypes that require advanced animations and responsive behavior using React + Framer Motion + Next.js.
Develop design-system components and documentation (Storybook) to scale UI primitives across teams, adding documented accessibility requirements and keyboard interactions.
Work on frontends for mobile-oriented consumer apps (web dashboards, landing pages, progressive web experiences) where tight integration with device features and imagery is required.

Repositories

The developer's experience in this domain has been verified based on AI analysis of the following repositories:

safetraq