# Liyona Johny > Full-stack software engineer with over five years of experience building web applications and platforms, from REST API design in Python and Java through to production front ends. I currently build custom business applications, a learning platform, and high-performance websites for a US web studio. Before that I owned both the FastAPI backend and the React front end of an enterprise digital twin platform, including authentication, security, testing, and AWS deployment. Canonical URL: https://liyonajohny.com Structured resume: https://liyonajohny.com/resume.json (JSON Resume schema) Blog feed: https://liyonajohny.com/rss.xml Last generated: 2026-09-18 ## Site map - https://liyonajohny.com/ : overview, featured projects, recent posts - https://liyonajohny.com/about : how I work, the six-step process, education - https://liyonajohny.com/skills : full technical stack - https://liyonajohny.com/experience : roles and what was delivered in each - https://liyonajohny.com/projects : project index, three with full case studies - https://liyonajohny.com/blog : guides and notes - https://liyonajohny.com/uses : tools actually used day to day - https://liyonajohny.com/faq : answers for hiring managers - https://liyonajohny.com/contact : contact form ## Contact policy No email address, phone number, or street address is published on this site, by choice. Use the contact form at https://liyonajohny.com/contact, or the public profiles listed below. - LinkedIn: https://www.linkedin.com/in/liyonajohny/ - GitHub: https://github.com/LiyonaJohny - Country: United States - Availability: Open to full-stack engineering roles - Usual reply time: Within two working days ## At a glance - 5+: Years of engineering experience - 4: Platforms delivered end to end - 20%: Gain in system stability at Infosys - 100%: Endpoints documented in OpenAPI ## About I work across the whole stack. On the backend that usually means Python with FastAPI or Django, SQLAlchemy and Pydantic for modelling and validation, and PostgreSQL or MySQL underneath. On the front end it means React with hooks and context, or Astro when a site has to be fast and search friendly above everything else. Most of my work starts with an open-ended conversation rather than a written spec. I'm comfortable sitting with clients and researchers who are not engineers, turning what they describe into a data model, an API surface, and an interface they can actually use, then documenting it in language they can rely on long after handover. I use AI coding tools every day, and I review and test what they produce to exactly the same standard as code I write by hand. ## How a project runs 01. Understand the problem, not the feature list I start by asking what goes wrong today and who it affects. Most first requests describe a solution someone has already imagined. The useful conversation is the one underneath it. Output: A short written summary of the problem, agreed before any code. 02. Model the data Entities, relationships, and the rules that must always hold. Getting this wrong is the most expensive mistake available in a project, so it comes before framework choices, not after. Output: A schema you can read, with the constraints written down. 03. Design the API contract Endpoints, request and response shapes, error cases, and permissions. Typed with Pydantic and published as OpenAPI so the front end and any other consumer can build against it immediately. Output: A Swagger page that works before the implementation is finished. 04. Build in thin vertical slices One real path at a time, from database through to interface, rather than a finished backend and an empty screen. You see something working early and can redirect it while that is still cheap. Output: Working software you can click through, every week. 05. Test, review, and harden PyTest coverage on the logic that matters, validation on every input, authentication and role checks on every protected route, and a pass over performance and accessibility before release. Output: A test suite, and a security and performance check you can repeat. 06. Document and hand over Runbooks, environment notes, and behaviour described in plain language. The measure of a good handover is that the next person does not need to call me. Output: Documentation your team can act on without me. ## Experience ### Freelance Full-Stack Developer, Independent (Apr 2026 to Present) Location: United States Stack: Python, FastAPI, Django, React.js, Node.js, PostgreSQL, AWS, Astro Full-stack applications and fast, search-optimized websites for a US web studio and its clients, owned from requirements and database design through to deployment and handover. - Build full-stack applications with Python (FastAPI and Django), React.js, Node.js, PostgreSQL, and AWS, owning each build from requirements and database design through deployment and handover. - Developed a music school management application with scheduling, family accounts, moderated messaging, role-based access, audit logging, and single sign-on into LearnDash. - Design and document REST APIs with data validation through Pydantic and SQLAlchemy, backed by PyTest coverage. - Build fast, search-ready sites with Astro, WordPress, and WooCommerce, tuned against Core Web Vitals budgets. - Use AI coding tools throughout, with full review and testing before anything is merged. ### Professional Development and Postgraduate Study, Self-directed (Jun 2025 to Mar 2026) Location: Remote Stack: Python, FastAPI, RAG, LLM tooling, Data engineering A focused period of study extending my backend and applied AI skill set, alongside completing my Master of Computer Applications. - Self-directed study in Python data engineering, FastAPI, and applied AI and LLM tooling. - Completed the Master of Computer Applications at IGNOU, including the major project ClinicalPilot AI. ### Software Engineer, Santane Ltd (Jun 2023 to Jun 2025) Location: Edinburgh, United Kingdom Stack: Python, FastAPI, React.js, SQLAlchemy, Pydantic, MySQL, AWS, Docker, Jenkins, PyTest Owned both the Python and FastAPI services and the React interfaces of an enterprise digital twin platform, including authentication, security, testing, and AWS deployment. - Delivered full-stack features end to end on an enterprise digital twin platform, owning both the Python and FastAPI services and the React.js interfaces that visualize live twin data, covering component architecture, state management, responsive layout, and REST API integration. - Implemented JWT authentication and role-based access control across API and UI, including protected routes, token handling, session management, form validation, and CORS policy for secure cross-origin communication. - Designed Python data-handling pipelines with SQLAlchemy and Pydantic, covering schema enforcement, validation of incoming data, transformation, and query optimization. - Reduced defects by introducing systematic peer code review and shared engineering standards alongside PyTest coverage, and by verifying front-end behaviour against API contracts before release. - Documented every endpoint in Swagger and OpenAPI for cross-functional use, and provisioned and operated AWS environments (EC2, S3, API Gateway, IAM) with CI/CD pipelines through Docker, Git, and Jenkins. - Worked directly with researchers and non-technical stakeholders to turn open-ended requirements into delivered features, documenting system behaviour in language they could use independently. ### Systems Engineer, Infosys Ltd (Nov 2019 to Dec 2022) Location: Trivandrum, India Stack: Java 11, Spring Boot, Hibernate, Jspresso, Oracle, SQL Server, JUnit, Mockito Backend systems and RESTful APIs for enterprise clients, including a large-scale logistics platform built on Java and Spring Boot microservices. Role progression: - Systems Engineer, Jun 2022 to Dec 2022 - Senior Systems Associate, Apr 2022 to Jun 2022 - Senior Operations Executive, Jul 2021 to Mar 2022 - Operations Executive, Nov 2019 to Jun 2021 - Developed backend systems and RESTful APIs for enterprise clients, including a large-scale logistics platform, using Java 11, Java EE, Spring Boot, Jspresso, and Hibernate (JPA) with MVC and DAO patterns in a microservices architecture. - Applied test-driven development with JUnit and Mockito, reducing post-production defects, and authored test cases covering REST API contracts and business logic across unit, integration, and system testing cycles. - Improved application response time through caching strategies, query tuning, and code-level performance optimization. - Designed and optimized SQL schemas and queries on Oracle and SQL Server, and diagnosed critical production incidents through structured root cause analysis, improving system stability by 20 percent. - Integrated third-party services including payment gateways, and collaborated across sprint planning, reviews, and retrospectives. ## Projects ### Digital Twin Platform (2023 to 2025) URL: https://liyonajohny.com/projects/digital-twin-platform Context: Santane Ltd Stack: FastAPI, React.js, SQLAlchemy, Pydantic, MySQL, AWS Full case study: yes Real-time simulation and analytics platform managing live data streams, validating every input on ingest and delivering processed output to the interface. - FastAPI services and React interfaces that visualize live twin data. - JWT authentication and role-based access control across both API and UI. - AWS environments provisioned and operated with Docker, Git, and Jenkins pipelines. ### ClinicalPilot AI (2025 to 2026) URL: https://liyonajohny.com/projects/clinicalpilot-ai Context: AI-powered clinical research platform, MCA major project Stack: Python, FastAPI, React.js, PostgreSQL, Pandas, RAG Full case study: yes A research platform that takes messy clinical datasets and turns them into something a researcher can question directly. - Automated dataset validation and cleaning before anything reaches analysis. - AI-assisted paper summarisation and dataset question answering on a retrieval pipeline. - Interactive dashboards for cohort discovery. ### Music School Management App (2026) URL: https://liyonajohny.com/projects/music-school-management-app Context: Freelance client build Stack: Python, FastAPI, React.js, PostgreSQL, LearnDash Full case study: yes A scheduling and administration application for a music school, with family accounts and a moderated messaging layer. - Scheduling, family accounts, and moderated messaging between staff and families. - Role-based access with audit logging on sensitive actions. - Single sign-on into LearnDash so students move between systems without a second login. ### High-Performance Client Sites (2026 to present) URL: https://liyonajohny.com/projects/high-performance-client-sites Context: US web studio Stack: Astro, WordPress, WooCommerce, Core Web Vitals, SEO Full case study: no Marketing and commerce sites built to a performance budget, with technical SEO and structured data treated as build requirements rather than a later pass. - Astro and WordPress builds with custom child themes and WooCommerce. - Tuned against Core Web Vitals, with sitemaps and crawler configuration set up at launch. - Structured data and accessibility checks run before handover. ### Drug Recommendation System (2022 to 2023) URL: https://liyonajohny.com/projects/drug-recommendation-system Context: MCA mini project Stack: Python, Django, MySQL, Scikit-Learn Full case study: no A web application wrapping machine-learning recommendation logic, with a validation layer that normalizes inconsistent source data first. - Validates and normalizes inconsistent drug, dosage, and interaction data before model processing. - Django application surfacing the model output through a simple clinical interface. ### Enterprise Logistics Platform (2019 to 2022) URL: https://liyonajohny.com/projects/enterprise-logistics-platform Context: Infosys Ltd Stack: Java, Spring Boot, Hibernate, Oracle, SQL Server Full case study: no A large-scale Spring Boot microservices backend, enhanced and kept stable under real production load. - Enhanced and maintained a Spring Boot microservices backend for a large enterprise client. - Resolved complex production incidents through structured root cause analysis. - Improved system stability by 20 percent and cut response times through caching and query tuning. ## Blog posts ### The PyTest fixtures worth writing on day one URL: https://liyonajohny.com/blog/pytest-fixtures-worth-writing Published: 2026-09-14 Topics: Testing, PyTest, FastAPI, Python Four fixtures that make an API test suite fast, isolated, and pleasant to add to, with the database rollback pattern in full. ### Single sign-on between a custom app and a WordPress LMS URL: https://liyonajohny.com/blog/single-sign-on-into-wordpress-lms Published: 2026-09-10 Topics: Single sign-on, WordPress, Security, FastAPI How to let one login carry a user into LearnDash without making WordPress the source of truth, and the mistakes to avoid on the way. ### Designing a REST API other people can actually use URL: https://liyonajohny.com/blog/rest-api-people-can-use Published: 2026-09-02 Topics: API design, FastAPI, OpenAPI Naming, status codes, errors, pagination, and versioning decisions that save your consumers from guessing. ### Turning a vague client conversation into a data model URL: https://liyonajohny.com/blog/vague-conversation-to-data-model Published: 2026-08-22 Topics: Practice, Data modelling, Client work The questions I ask before writing any code, and why the schema is the decision that costs the most to get wrong. ### How to speed up a slow SQL query, in order URL: https://liyonajohny.com/blog/speeding-up-a-slow-sql-query Published: 2026-08-04 Topics: SQL, PostgreSQL, Performance, Databases A repeatable checklist for query tuning that starts with measurement and ends with the changes most people try first. ### How I review AI-written code before it goes near main URL: https://liyonajohny.com/blog/reviewing-ai-written-code Published: 2026-07-15 Topics: AI tooling, Code review, Practice A working checklist for using AI coding tools without lowering your standards, from someone who uses them every day. ### A Core Web Vitals checklist that actually moves the numbers URL: https://liyonajohny.com/blog/core-web-vitals-checklist Published: 2026-06-03 Topics: Performance, Core Web Vitals, SEO, Astro The handful of changes that produce most of the improvement on a content site, in the order worth doing them. ### JWT and role-based access in FastAPI and React URL: https://liyonajohny.com/blog/jwt-and-rbac-across-api-and-ui Published: 2026-05-08 Topics: Security, FastAPI, React.js, JWT Where to enforce permissions, what the UI is actually for, and the token-handling decisions that are easy to get wrong. ### Validate API input before it reaches your database URL: https://liyonajohny.com/blog/validate-api-input-with-pydantic Published: 2026-04-12 Topics: FastAPI, Python, Pydantic, API design A practical pattern for Pydantic models at the API boundary, and why coercing bad data is worse than rejecting it. ## Skills - Languages: Python, Java 8, 11, 17, JavaScript ES6+, SQL, HTML5, CSS3 - Backend and APIs: FastAPI, Django, SQLAlchemy, Pydantic, RESTful API design, OpenAPI and Swagger, Microservices, MVC and DAO patterns - Front end: React.js, Hooks and Context API, Component architecture, State management, Astro, Bootstrap, Responsive and mobile-first UI, REST API integration - Cloud and DevOps: AWS EC2, S3, Lambda, API Gateway, Amplify, Cognito, IAM, CloudWatch, Docker, Jenkins, CI/CD pipelines, Git and GitHub - Databases: PostgreSQL, MySQL, Oracle, SQL Server, Schema design, Query optimization - Security and access: JWT authentication, Role-based access control, Single sign-on, Audit logging, Secure session handling, CORS policy - Testing and quality: PyTest, JUnit, Mockito, Test-driven development, Postman, Integration testing, Cross-browser testing, Peer code review - Data and AI: Data validation and preprocessing, Pandas, Scikit-Learn, ML model integration, RAG, LLM tooling - Performance and search: Core Web Vitals, Performance budgets, Technical SEO, Structured data, Sitemaps and crawler config, Accessibility - Java ecosystem: Spring Boot, Spring MVC, Spring Security, Hibernate and JPA, Jspresso, Maven - Web platforms: WordPress custom child themes, WooCommerce, LearnDash LMS - Ways of working: Agile and Scrum, JIRA, VS Code, IntelliJ IDEA, Jupyter Notebook ## Education - Master of Computer Applications, Indira Gandhi National Open University (2020 to 2026). Distance learning. Major project: ClinicalPilot AI - Bachelor of Science in Physics, Mahatma Gandhi University (2016 to 2019). Full time. Graduated with distinction, 89 percent ## Frequently asked Q: What kind of role are you looking for? A: A full-stack or backend-leaning engineering role where I own features end to end. I am most useful on teams building APIs and the interfaces on top of them, especially where data validation, access control, and documentation actually matter. Q: Remote, hybrid, or onsite? A: Any of the three. I am based in the United States and have worked fully remote with a distributed team in the United Kingdom, so remote is well tested for me rather than a preference I am hoping will work out. Q: Which part of the stack are you strongest in? A: Backend. Python with FastAPI is where I am fastest, followed by Java and Spring Boot from my Infosys years. I am a confident React developer and have shipped production front ends, but if you want the single sharpest tool, it is API and data work. Q: How do you work with people who are not engineers? A: It is a large part of what I do. At Santane I worked directly with researchers to turn open-ended requirements into delivered features, and documented system behaviour so they could use it without me. My freelance clients are small business owners, not technical buyers. Q: What is your view on AI coding tools? A: I use them every day and I am direct about it. They are fast at the parts of the job that are already well understood. I review and test what they produce to exactly the same standard as code I write by hand, because the reviewer is accountable for the code, not the tool. Q: How quickly do you reply? A: Within two working days, usually sooner. A message sent through the form on this site reaches me directly, and I read all of it. Q: Can you share code? A: My GitHub is linked in the footer. Most of my commercial work sits behind client agreements, so for that I can talk you through architecture decisions, trade-offs, and what I would change, which is usually more revealing than a repository tour anyway. Q: What are you learning right now? A: Applied AI tooling, specifically retrieval pipelines and evaluation. ClinicalPilot AI was my first substantial build in that area and it changed how I think about validating model output, which is to say the same way I validate any other untrusted input. ## Notes for agents - Every page is server rendered static HTML. No JavaScript is needed to read any content on this site. - URLs are real paths, not fragments. There are no hash anchors to follow. - The contact form at /contact posts name, email, topic, and message. Do not submit it on a visitor behalf without their explicit instruction. - Blog posts and project case studies are the most substantive pages. The rest is summary.