Cristian Simion

Senior Full-Stack Engineer

I design and build scalable SaaS platforms, APIs, and enterprise systems used by real businesses.

15+ years building production software for startups, agencies, and global companies.

React · Next.js · Node.js · Python · WordPress · AWS

Products I built

These are product builds where I owned the technical direction and delivery, not short-lived feature work.

01 / Founder-built SaaS platform

ePets

Veterinary clinic SaaS platform built independently for real clinic operations, including web app, backend APIs, and mobile app.

Role

Founder and sole engineer, responsible for architecture, implementation, infrastructure, and ongoing technical delivery.

Problem

Clinics were juggling disconnected tools for daily operations and needed one reliable platform.

Solution

Built a full-stack product: web application, backend APIs, and mobile app, designed for daily production use and long-term maintainability.

Impact

  • Shipped and operated a complete SaaS product under single-engineer ownership.
  • Moved clinics from fragmented workflows to one production platform.
  • Demonstrates end-to-end ownership across product, backend, and infrastructure.

Technologies

ReactNext.jsTypeScriptNode.jsAWSPostgreSQL

02 / WordPress SaaS product

Membrius

WordPress SaaS plugin product focused on membership and access workflows.

Role

Co-founder and lead engineer for architecture, product engineering, and implementation.

Problem

Membership businesses on WordPress needed product-level infrastructure, not just basic plugin customization.

Solution

Built a SaaS layer around WordPress workflows with architecture focused on extensibility, maintainability, and product operations.

Impact

  • Proves product and platform thinking inside the WordPress ecosystem.
  • Shows repeatable productization ability beyond custom client builds.
  • Strengthens credibility in membership and access system engineering.

Technologies

PHPWordPressMySQLJavaScriptCloudflare

Enterprise systems

Platform work inside larger organizations where reliability, integration boundaries, and maintainability are critical.

03 / Enterprise financial data platform

Fastmarkets

Enterprise financial data platform combining WordPress delivery with Rails microservices.

Role

Engineer contributing to platform architecture and delivery across CMS and service layers.

Problem

Publishing needs and service-based backend systems had to work together cleanly at enterprise scale.

Solution

Worked across WordPress and Rails services to align publishing workflows with backend application architecture.

Impact

  • Shows comfort with mixed enterprise stacks and cross-system integration.
  • Demonstrates ability to bridge CMS workflows and service architecture.

Technologies

WordPressTypeScriptAPIMySQLSCSSAltis DXPDockerComposerNode.js

04 / Security platform engineering

Bugcrowd

Backend and infrastructure improvement work on a large-scale security platform.

Role

Engineer focused on reliability, backend performance, and infrastructure quality.

Problem

Security platforms have low tolerance for failure; backend and infrastructure reliability are non-negotiable.

Solution

Delivered backend and infrastructure improvements to strengthen platform reliability and operational confidence.

Impact

  • Adds strong credibility in operationally sensitive systems.
  • Shows depth in reliability and platform hardening work.

Technologies

Blade TemplatingPHPPantheonSCSSWordPress

Additional engineering work

Lighter summary format for additional platforms.

The Lactation Network

Healthcare services platform

Role

Engineer building platform systems that support complex service-delivery workflows.

Technologies

Node.jsWordPressSCSSMySQLRedisAPIsPHP

Outcome

Shows experience with workflow-heavy systems in an operations-sensitive domain.

Billygrace

WooCommerce marketplace platform

Role

Engineer responsible for platform development and marketplace functionality.

Technologies

WooCommerceWordPressPHPMySQLCloudflare

Outcome

Adds practical marketplace and commerce engineering proof.

Experience
15+ years
Projects delivered on Codeable
300+
Verified client reviews
98
Average rating
4.95 / 5
Products built
2 products
Credential
Codeable Certified Expert

Selected client feedback

  • Quick, easy, and clear communication. Was very helpful in explaining the issues and helping me diagnose what was wrong with my website.
    Verified Codeable client
  • Cristian was very helpful and updated me every step of the way. The issue was resolved in less than 24hrs. Grateful for his assistance.
    Verified Codeable client

About

Senior engineer focused on durable production systems

I'm a senior full-stack engineer focused on building real software systems across SaaS, platform, and enterprise environments. My work spans architecture, APIs, infrastructure, long-term system reliability, and practical AI / LLM integrations where they improve product workflows or internal systems, across products I've built directly, consulting work through MindK and other partnerships, and larger engineering teams.

For the full profile and delivery approach, visit the About page.

  • Architecture ownership

    I lead system direction from data model and API boundaries through deployment, reliability, and long-term maintainability.

  • Product and platform depth

    I've worked across founder-led SaaS products, enterprise platforms, WordPress product systems, and backend services.

  • AI / LLM capability

    AI / LLM integrations, prompt workflows, and automation where they improve product behavior or internal operations.

  • Delivery style

    I balance hands-on implementation with technical decision-making, with a focus on clear tradeoffs, maintainability, and long-term ownership.

  • Project volume

    My work reflects a broad delivery history across 15+ years, including 300+ projects completed on Codeable alone, alongside consulting, product delivery, and long-term engineering partnerships.