Jobs Node.js

We are an outsourcing company looking for a Full-Stack JavaScript Developer to join our client — a product company providing hosting and co-location services. The client is actively developing their own infrastructure control panel / client portal used for provisioning services, managing servers and billing.

The product is already in production and used daily by internal teams and customers. At the moment, the main focus is on stability, edge cases and overall product quality rather than adding new features.

The product is a SaaS admin panel for hosting and infrastructure services. The backend integrates with VMware vSphere API through an internal abstraction layer, so experience with infrastructure or virtualization concepts will be a strong advantage.

The tech stack includes Svelte on the frontend and Node.js (Express) with JavaScript on the backend. Swagger / OpenAPI is used for API documentation. The team works in Slack (English), ClickUp, with weekly planning. There are testing, staging and production environments (moving to feature-branch workflow).

In this role you will own features end-to-end (frontend and backend), fix bugs, regressions and edge cases, maintain and extend the existing API (100+ endpoints), and work with Svelte UI flows focused on functionality rather than design. There is no designer and no Figma-based workflow — UI decisions are based on the existing product. You will do basic developer-level testing and work closely with system administrators who validate changes on real servers.

We are looking for a developer with strong Node.js / Express / REST API experience, comfortable working in an infrastructure-oriented product. Swagger / OpenAPI experience is a plus. You should have a practical debugging mindset, be able to quickly reproduce and fix issues, communicate confidently in English and feel comfortable working without a heavy design or UX process.

Nice to have: experience with VMware / vSphere, hosting panels, infrastructure automation, Kubernetes basics or DevOps background.

We offer a 1-month paid trial on real backlog tasks, followed by a performance review. If everything goes well, this is a long-term cooperation. The product is stable, the client is profitable and plans long-term development of the platform.

Description:

We are looking for a Senior Software Engineer to design, build, and evolve a robust serverless backend infrastructure. You will take ownership of cloud engineering initiatives, ensure system reliability and scalability, and help shape an AI-first development culture. This role involves architecting distributed systems, scalable APIs, and secure payment and subscription integrations, all while maintaining enterprise-grade standards for performance and reliability.

Requirements:

• 10+ years of professional software development experience.
• Advanced proficiency in Node.js and Python with a strong grasp of asynchronous programming.
• Hands-on experience with AWS serverless technologies (Lambda, API Gateway, DynamoDB, S3, SQS, SNS).
• Strong knowledge of database design and optimization (SQL and NoSQL).
• Experience implementing CI/CD pipelines and automated testing frameworks.
• Demonstrated expertise in site reliability engineering (SRE), including monitoring and failover strategies.
• Excellent analytical and communication skills with the ability to work in distributed teams.
• Background in SaaS product development and familiarity with SaaS-specific scalability challenges.
• Experience working within Agile methodologies.
   

Would be a plus:

• Familiarity with AWS security and compliance best practices.
• Experience in real-time analytics or event-driven architectures.
• Knowledge of C# or additional backend languages.
• Experience designing microservices architectures.
• Exposure to high-traffic consumer applications.
• Understanding of networking and URL routing logic (e.g., link shortening and redirection).
   

Duties:

• Architect and build scalable, high-availability backend systems leveraging serverless cloud technologies.
• Collaborate closely with product, design, and operations teams to deliver seamless user experiences.
• Lead AI-driven engineering initiatives, ensuring long-term maintainability and scalability.
• Mentor and guide engineers, promoting a culture of technical excellence.
• Design, develop, and maintain backend services in Node.js and Python within AWS environments (Lambda, API Gateway, DynamoDB, SQS, SNS, etc.).
• Collaborate with front-end teams for efficient client-server integration (React.js).
• Implement best practices in monitoring, logging, and automated alerting.
• Conduct code reviews, troubleshoot production issues, and drive continuous improvement.
• Maintain clear and comprehensive technical documentation.
• Proactively identify architectural enhancements to improve system resilience and performance.
• Work autonomously with a strong sense of ownership and accountability.

Benefits:

• A competitive salary and flexible compensation package
• Flexible working format: remote, office-based, co-working space
• Professional development tools (mentorship program, tech talks and trainings)
• Medical insurance
• Free corporate English classes and speaking clubs with a native speaker
• Various corporate events

This is a fully remote opportunity for a Software Engineer with solid experience in Node.js who is motivated to grow and take on new challenges. We are looking for a specialist with 3+ years in software development, confident in building backend solutions, working with microservices, and writing efficient raw SQL. You should be comfortable working directly with Node.js, mainly using Express or Fastify.
As the team is distributed, participation in all regular video calls (daily stand-ups, weekly meetings, team sessions) is expected. An up-to-date LinkedIn profile will also be required as part of the recruitment process.

Responsibilities

• Design, develop and support backend services using Node.js.
• Work closely with product, data and engineering teams to deliver new features.
• Investigate, fix and prevent issues to ensure system stability and code quality.
• Participate in code reviews and contribute to improving engineering practices.
• Follow modern backend trends and propose technical improvements.

• Take ownership of complex tasks and quickly adapt to new technologies and tools.

   

Requirements

• 3+ years of experience in software development with a strong focus on backend and raw Node.js.
• Confident work with Express and/or Fastify.
• Experience building and maintaining microservices.
• Strong knowledge of relational databases and hands-on work with raw SQL.
• Experience with message brokers (Kafka is a strong plus / requirement).
• Experience integrating with external systems via APIs and different protocols (REST, Pocket, etc.).
• Ability to analyze large volumes of data and identify anomalies related to risk and fraud.
• Understanding of security best practices and data protection.
• Strong problem-solving skills and ability to work in a fast-paced startup environment.
• Good communication skills and ability to work effectively in a remote team.
• Proactive mindset and willingness to learn.
• Knowledge of Python and/or PHP is a plus.

What we offer:
- Flexible work format - remote, 8-hour working day without time trackers;
- Competitive salary;
- Tight-knit and friendly team;
- Personalized career growth;
- Up to 50% coverage of the cost of professional courses;
- Vacation time, sick-leaves, national holidays ;
- Competitive bonuses for a personal recommendation of new employees;
- Professional development tools (mentorship program, tech talks and workshops);
- English classes with a teacher;
- Corporate events and team buildings.

• Project Description:

  We are looking for a Front-End Developer who can contribute immediately to a viewer technology migration and help establish a long-term visualization framework for oil and gas service company. You will work closely with cross-functional teams and regional experts to design, implement, and support solutions with a focus on data security and global availability to facilitate data-driven decisions for our customers.
   

• Responsibilities:

  1. Design and Development: Plan and implement new functionality and features in globally deployed E&P services.
  2. Shape enterprise-level user experiences: Model, create, and improve the next generation of user experiences for E&P customers.
  3. Automation: Develop and maintain automation CI/CD pipelines to handle all stages of the software lifecycle.
  4. Monitoring and Troubleshooting: Monitor customer environments to proactively identify and resolve issues while providing support for incidents.
  5. Data Security: Implement and consistently improve measures to protect sensitive information and ensure compliance with regulations.
  6. Documentation: Write and maintain documentation for processes, configurations, and procedures.
   

• Mandatory Skills Description:

  Core Front-End Experience
  5+ years of professional experience in modern JavaScript/TypeScript development
  Strong proficiency in HTML5, CSS3, layout systems (Flex/Grid), and responsive design
  Experience in building reusable UI components and visualization layouts
  Strong expertise in Angular (with TypeScript), Node.js Backend and PrimeNG
  Excellent understanding of UI component architecture, state management, and performance optimization
  
  Visualization & UI Development
  Experience developing custom chart components, dashboards, or interactive UIs
  Ability to work with Canvas/SVG at the level needed to build ECharts-like components (full computer graphics knowledge not required)
  Good understanding of performance considerations for complex UI rendering (efficient DOM updates, throttling, virtualization)
  
  General Skills
  Solid grasp of modular architecture and extensibility
  Ability to translate visualization requirements into clean, maintainable front-end modules
  Familiarity with data-driven UI design and rendering patterns

About us:
BetterMe — a global wellness ecosystem empowering millions to become better — physically, mentally, and emotionally. We build what makes people better and keep challenging ourselves to inspire others.

Your Impact:

• Work closely with the backend team to create and implement onboarding funnels and quizzes;
• Write reusable, testable, and efficient code;
• Take responsibility for various components of the backend infrastructure;
• Engage in effective communication with DevOps and product teams;
• Participate in decisions regarding application architecture and database design.

About you:

• At least 1 year of professional experience with TypeScript, Node.js, Express, and Nest.js;
• Strong knowledge of JavaScript and TypeScript;
• Experience or deep understanding of Cloud services (AWS is a plus);
• Proficient in working with relational databases;
• Knowledge of DevOps practices;
• Experience with Git and CI/CD processes;
• Understanding of SOLID principles. 

Would be a plus:

• Work experience in high-load projects;
• Experience working on microservices-oriented projects;
• Experience with AWS.

For a clearer comprehension, feel free to familiarize yourself with our technology stack:

• Databases: MySQL, TypeORM
• Backend: Node.js, Nest.js
• Cloud & Orchestration: Kubernetes, AWS

• Version Control & Collaboration: GitHub

   

What you get at BetterMe: 

A mission that inspires. Every line of code, every design, every idea helps millions of people become healthier and more confident.
Trust without micromanagement. You manage your time and make decisions independently. We value outcomes, not online hours.
Growth opportunities. 90% of our leads have grown within the company. There’s space for initiative, new responsibilities, and real career upgrades.
Flexible work format. Choose what works best for you — office, remote, or hybrid.
Wellness in practice. Offline: workouts with professional trainers in our corporate gym, massage, corporate lunches, sports, and team activities — everything you need to recharge and reset together. Online: regular online workouts, partner discounts, and free access to our products.
Health insurance & corporate doctor.
Time off & balance. 20 paid vacation days, paid sick leave, and additional days off around public holidays.
Open communication. Transparency across teams, honest feedback, and support for initiatives are part of our everyday culture.
Support for sports events. We cover entry fees and encourage the team to compete and participate together.
Modern equipment. We provide new hardware and everything you need for productive work.
Legal & finance support. Experienced lawyers and financial specialists are always there to help — from documents to personal consultations.

Find more about us on social media platforms: Instagram, LinkedIn.

We’re building a high-performance, intelligence-driven trading platform operating across Chat, Web, and internal data systems. 

We’re looking for a senior full-stack engineer who can take on large, ambiguous problems and turn them into production-grade features with minimal supervision. You should be deeply comfortable with React/Next.js frontends, Node.js backends, and modern application patterns.

You Will:

- Ship high-quality features end-to-end across Node.js APIs and Next.js frontends

- Optimize performance, data flows, caching, and component architecture

- Improve existing codebases with strong engineering discipline (testing, structure, clarity)

- Integrate with internal APIs, trading engines, and real-time data surfaces

- Operate independently inside high-tempo dev cycles

Requirements:

• 5+ years full-stack experience

• Expert in Node.js, React, Next.js

• Strong with TypeScript, API design, and system-level thinking

• Excellent communication - able to articulate reasoning and tradeoffs clearly

• Prior experience in fast-paced startups or high-ownership environments

Nice to Have:

• Experience with WebSockets, real-time systems

• Familiarity with PostgreSQL, Redis, caching layers

• Background in trading, finance, or data-intensive systems

• Experience in Solana, DeFi protocols, or trading systems

We are looking for a Full Stack Developer with strong experience in React, TypeScript, and Node.js (Express or NestJS) to join our team on a short-term client project (full-time for 1 month).
The ideal candidate is comfortable working across the entire stack — building intuitive, high-quality frontend interfaces while developing secure and performant backend services and APIs.

This role includes working with complex XML data flows, implementing XSD validation, and collaborating closely with DevOps and frontend engineers to deliver production-ready features within a tight timeframe.

Responsibilities

• Develop responsive, scalable UI components using React and TypeScript
• Build and maintain backend services using Node.js and Express
• Design and implement secure, performant REST APIs with validation, authentication, and rate-limiting
• Handle XML data workflows and apply XSD schema validation in backend systems
• Work with MongoDB, Mongoose, and Prisma ORM for efficient data management
• Manage authentication using JWT and bcryptjs
• Integrate third-party services: AWS S3 (file storage), Stripe (payments), Twilio (SMS), Nodemailer (emails)
• Handle file uploads securely using Multer and AWS SDK
• Generate documents using tools like pdfkit, puppeteer, and marked
• Write unit/integration tests, perform code reviews, and follow clean architecture practices

• Monitor application performance using tools like New Relic and Winston logging

   

Requirements

• 3+ years of professional experience in frontend development with React and TypeScript
• 3+ years of backend development experience using Node.js and Express
• Strong understanding of REST APIs, JSON/XML, and full-stack integration
• Practical experience working with XML/XSD validation
• Experience with Git/GitHub workflows and CI/CD pipelines

• Familiarity with containerized environments (Docker)

   

Nice to Have

• Experience with form-heavy interfaces, dashboards, or workflow-based UIs
• Familiarity with Redis for caching or real-time use cases
• Experience working in microservices architecture
• Understanding of accessibility (WCAG), responsive design, and performance optimization.

An innovative startup operating at the intersection of AI and real-time communication.

Our goal is to build a modern web application with intelligent algorithms, low-latency interactions, and a self-hosted infrastructure at its core.
 

Your responsibilities

• Develop and maintain a web application using Next.js
• Implement real-time features with WebRTC / LiveKit
• Work with Supabase (Postgres), including local development and setup
• Build clean, scalable UI using Tailwind CSS and shadcn/ui
• Improve system architecture, CI/CD, GitOps, and manage deployments on Vercel
• Actively use AI-powered tools (ChatGPT, Gemini, Claude, Cursor) in daily development workflows
   

Must-have requirements

• Strong expertise in Next.js and the React ecosystem
• Solid full-stack experience with TypeScript / JavaScript
• Hands-on experience with WebRTC (chat or video applications)
• Experience with an ORM: Drizzle (preferred) or Prisma
• Confident use of Git / GitOps
• Regular use of AI assistants for software development
   

Nice to have

• Experience with Stripe integration or Firebase
• Knowledge of Docker, GitLab CI/CD, and pipeline setup
• Familiarity with Cloudflare Workers or Edge Computing
• Basic knowledge of Python
   

Gamzix company, a dynamic player in the iGaming industry:

• Was founded in March 2020 with a vision to redefine the world of online slot games
• Has already successfully produced 60 slot games
• The team has grown to over 120 skilled professionals, and we continue to grow
• Our main hub is in Warsaw — right in the heart of Europe
• With a strong focus on quality and compliance, we hold the prestigious MGA B2B
• Critical Supply License and certifications from industry leaders iTechLabs and GLI, ensuring the highest standards

Hey there! 👋

The Gamzix team is growing, and we’re looking for a Junior Backend Engineer (Node.js) who is eager to grow, learn modern backend technologies, and contribute to the development of our slot games and internal systems under the guidance of experienced teammates.

If you’re passionate about backend development, want to work with real production systems, and grow within a strong engineering team — we’d love to meet you!

Responsibilities:

• Participate in the development and support of backend services under the guidance of senior engineers
• Assist in building and maintaining APIs
• Work with databases and backend logic (queries, data handling)
• Collaborate with the team on bug fixes, improvements, and new features
• Follow best practices for clean, readable, and maintainable code
• Learn and apply backend architecture principles, asynchronous processing, and system reliability concepts

Requirements:

• 1+ year of commercial or strong pet-project experience in backend development
• Basic to solid knowledge of Node.js and TypeScript
• Familiarity with NestJS (commercial or learning projects)
• Understanding of relational databases (PostgreSQL or similar)
• Basic experience or theoretical knowledge of Redis and message brokers (RabbitMQ or аналог)
• Understanding of REST APIs and backend fundamentals
• Willingness to learn, ask questions, and grow professionally

What we offer:

• Market-level salary in the IT/Gaming industry
• Relocation support to Warsaw
• Referral bonus — bring in awesome people and get rewarded
• Home-Office coverage
• 7-hour working day: 10:00–18:00 (including lunch break)
• Hybrid model in Warsaw; full remote — for other locations
• Paid Sick Leave: up to 10 working days per year
• Paid Time Off: 18 vacation days, 10 days off, paid state holidays
• Corporate benefits: medical coverage, sports compensation, psychological services compensation
• Professional Development Support: reimbursement for external courses, training & certifications
• Corporate English classes (Business or General) — flexible timing
• Buddy Program
• Internal Gamzix Store (earn coins & exchange for branded gifts)
• Corporate team building and activities
• Open and transparent communication — accessible C-levels, quick decision-making, friendly and supportive atmosphere
   

Our people are passionate professionals who truly enjoy what they do. At Gamzix, your ideas matter, teamwork drives results, and everyone keeps up with the fast-paced rhythm of the iGaming industry.
 

Please note: feedback on your application will be provided within two weeks if a positive decision is made regarding your candidacy.
 

I give my consent in accordance with the Law on the Protection of Personal Data dated June 1, 2010, No. 2297, effective from January 1, 2011, for the processing of personal data.

Tech Stack:
• Backend: Node.js with Nest.js

• AWS
• Database: PostgreSQL with RDKit integration, Prisma ORM
• REST, Swagger
• Unit & e2e tests

We offer:

• Cooperation with a stable company with well-established processes and a positive atmosphere
• Experience in project management of different levels of complexity, methodology, and approaches
• Flexible schedule: Mon-Fri (8 hours a day)
• 18 days of paid vacation; 15 days sick leave
• A decent level of remuneration with regular reviews of the results of cooperation
• Extensive loyalty program 

Responsibilities:
• Build and maintain front-end features using React, Next.js, TypeScript, Tailwind, shadcn/ui
• Develop scalable back-end services with Node.js, Nest.js, TypeScript
• Implement real-time functionality using WebSockets
• Design and maintain data layer with PostgreSQL + TypeORM
• Work with async messaging via RabbitMQ
• Support infrastructure on DigitalOcean + Cloudflare

Requirements:
• Strong experience with TypeScript (FE & BE)
• Hands-on with React + Next.js
• Solid backend skills with Node.js / Nest.js
• Experience with PostgreSQL, ORMs, and real-time systems

We offer:

• Cooperation with a stable company with well-established processes and a positive atmosphere
• Experience in project management of different levels of complexity, methodology, and approaches
• Flexible schedule: Mon-Fri (8 hours a day)
• 18 days of paid vacation; 15 days sick leave
• A decent level of remuneration with regular reviews of the results of cooperation
• Extensive loyalty program 
   

Summary
We are looking for a skilled fullstack developer to support the further development of a production-grade web application. The stack includes Angular (latest version) as the frontend framework, NestJS for the backend, MariaDB as the database, and Keycloak for authentication and authorization. We use TypeORM for data access.

Responsibilities:

• Build and maintain Angular components (standalone components, Signals)
• Extend and improve REST APIs using NestJS
• Manage the MariaDB database schema and migrations using TypeORM
• Implement and maintain Keycloak-based authentication, including role-based access control
• Write end-to-end tests using Playwright or Cypress
• Ensure high code quality and contribute to technical documentation
   

Requirements:

• Strong experience with Angular (v16 or newer), including Signals
• Proficiency with NestJS and modular backend architecture
• Solid TypeScript knowledge
• Hands-on experience with MariaDB and TypeORM
• Real-world experience integrating Keycloak into fullstack apps
• Experience with Playwright or Cypress for end-to-end testing
• Familiarity with Docker, Git, and CI/CD pipelines
• Independent and reliable working style
• 5+years in general as developer, angular and node -3y, nest - any exp
   

Project Info:

• The application is already live and actively used
• Tasks are well-defined and managed via GitLab
• Collaboration with an internal development team
• Modern, containerized infrastructure
• We’re looking for someone who can get started soon. If the collaboration works well, long-term cooperation is possible.
  
  Stages:
  - HR call
  - Technical
  - Need to record a video where the candidate talks about their latest project with Angular+Nest !!!

OneTablet builds software used daily by restaurants to run their online ordering across Uber Eats, DoorDash, Grubhub, and more — reliably, at scale, without chaos.

We’re an early-stage product company with real customers, real traffic, and real production problems. We’re looking for a senior backend engineer who owns systems end-to-end, is comfortable with ambiguity, and likes building infrastructure and integrations that don’t break at 7pm on Friday.

What you’ll do

• Build and own deep third-party integrations (DoorDash, Grubhub, POS systems, delivery platforms)
• Design reliable backend systems: ingestion, sync, reconciliation, retries, monitoring
• Work on infrastructure & scalability (GCP, Pub/Sub, queues, background workers)
• Use AI in daily work: debugging, refactoring, automation, internal tools, agents
• Take ownership from design → production → incidents → improvements

What we expect

• Strong backend experience (Node.js / TypeScript)
• Experience with integrations, APIs, webhooks, async flows
• Startup / product environment experience (early-stage, small teams, fast iteration)
• Production mindset: logging, monitoring, edge cases, failure modes
• High autonomy: you don’t wait for specs, you clarify and move
• Comfort using AI tools as part of development (Cursor, Claude, etc.)

Nice to have

• Experience with payments, ordering, POS, or marketplace platforms
• GCP, Pub/Sub, BigQuery, PostgreSQL
• Interest in automation and AI-first workflows

How we work

• Small senior team, no micromanagement
• High trust, high ownership
• Direct communication, fast decisions
• You build it → you own it

THIS IS A PROJECT-BASED POSITION

ABOUT THE COMPANY

Whimsy Games is an outsourcing game development company known for creating innovative and entertaining games for various platforms. With a focus on creativity, Whimsy Games constantly explores new ideas and pushes game development’s boundaries. In the next few years, we aim to create bestsellers and become a respected partner for global GameDev companies.
 

Project Information: USA, Social Casino, Sweepstakes
 

Responsibilities:

• Develop and maintain core features of the iGaming platform
• Design and implement scalable and secure business logic
• Integrate third-party services (games, payments, providers, APIs)
• Ensure performance, reliability, and security of backend services
• Participate in architecture decisions and code reviews

• Collaborate closely with product managers and designers

   

Position Requirements:

• Strong knowledge of JavaScript / TypeScript
• Experience with Node.js (NestJS / Express / Fastify)
• Frontend experience (React) is a plus
• Understanding of REST APIs and/or GraphQL
• Experience with databases (PostgreSQL / MySQL / MongoDB)
• Knowledge of async programming and performance optimization

• Understanding of security basics (auth, permissions, data protection)

   

It will be a big plus if the candidate has:

• Experience in iGaming / Gambling / Betting projects
• Experience with high-load systems
• Knowledge of WebSockets / real-time features
• Experience with Docker, CI/CD, cloud platforms

• Familiarity with microservices architecture

   

Why Join Us?

• Real Product, Real Impact: Work on a live product, not an experimental project.
• Technical Ownership: Direct influence on architecture, technical decisions, and long-term system design.
• Long-Term Collaboration: Stable project with a long-term roadmap and clear product growth vision.
• Flexible Work Environment: Work from anywhere globally with a competitive compensation package.
• Dynamic Team: Join a group of passionate game development experts who share your love for creativity and innovation.
• Regular Sync-Ups: Participate in company-wide meetings to share ideas and feedback, and collaborate with the team.
• Fun and Supportive Culture: We foster a collaborative, supportive team environment where your ideas and contributions are valued.

ABCloudz is a dynamic technology company specializing in software development, modernization, and digital transformation, with a strong focus on building AI-driven solutions.
We are looking for a motivated Trainee Software Engineer who is eager to grow in development and take part in AI research and implementation.
If you already have a foundation in JavaScript, TypeScript, and Python and want to develop your skills while working with AI and Web3 technologies, this is the perfect opportunity to start your career and Internship Program with us.

Requirements

• Willingness to learn and thirst for knowledge
• Basic knowledge of Object Oriented Programming
• Solid knowledge of Java Script and TypeScript
• Knowledge of Python
• Understanding of basic NodeJS concepts
• Understanding REST API
• Experience with Linux-like OSs, console
• Basic understanding of algorithms and data structures
• Basic knowledge of Git, Docker (console or UI clients)
• Experience with relational DBs, basic SQL knowledge

• At least the Intermediate level of English

   

Will be a plus

• Understanding WebSockets
• Understanding software architectures and architecture patterns
• Familiarity with module testing
• Understanding NoSQL DBMS (MongoDB, Redis)
• Familiarity with Nest.JS
• Familiarity with LLM and ML

• Familiarity with web3 technologies

   

Responsibilities

• Develop and maintain backend features using Node.js and NestJS under guidance
• Implement REST and basic GraphQL endpoints following existing patterns
• Contribute to microservice-based applications
• Implement simple inter-service communication using NATS or RabbitMQ. Handle basic event publishing and consuming
• Assist in integrating LLM-based features using existing SDKs or APIs
• Interact with blockchain networks using libraries
• Assist in implementing wallet-based authentication
• Implement and test smart contract interactions
• Write clean, readable, and well-documented code
• Fix bugs and address technical debt in existing services
• Write basic unit tests (Jest)
• Participate in code reviews (as a learner)