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desalasworks presents:

a portfolio of work by steven de salas

Stuart

Building real-time core backend infrastructure for Pan-European delivery logistics.

 

Steven helped build and launch Stuart’s mobile backend streaming functionality providing realtime platform updates, routing millions of delivery requests every week across 100s of European cities. Helping Stuart maintain its reputation for hyper-reliability as well as introducing improvements to company-wide engineering, QA and security practice.

Tech Stack

Redis PubSub, Event-based architecture, WebSocket protocol, Node.js, Express, TypeScript, OpenAPI, Kubernetes, AWS, DevOps, Prometheus, Thanos, Grafana. Kafka. Auto scaling. Graceful shutdown. Test automation. K6. SonarCloud. ZAP Scan. Authentication. JWT. ECDSA Web crypto API, Observability dashboards. Mentoring.

Key Deliverables

The mobile app team was looking to scale its functionality but was being held back by slow progress. The key deliverable to unblock them was to extract the core message streaming functionality so that it could be iterated and built upon, by putting it into a separate Kubernetes hosted service, built using Node.js and TypeScript and WebSockets, with Redis as the pub/sub fanout mechanism.

The project was a success. Delivered on time and within budget while leading a small team of engineers. In addition to the project goals Steven also worked on creating several other APIs (feature flags, device log streaming) and made company-wide improvements to DevEx, QA and Security practice.

Feedback

Here is feedback on Linkedin. From Pau Picas and Sergi

Steven is an outstanding engineer. In the short time he was at Stuart, Steven was able to ‘hit the ground running’ and made a significant contribution by implementing a notification system to allow the real-time processing of delivery requests in the mobile app. This ensured that critical data was reliably processed, and performance-tested at scale, paving the path for us to reliably scale our platform.

Steven’s technical proficiency in Node.js and backend APIs, coupled with his ability to collaborate across teams, made him an invaluable asset. I highly recommend him for any role that values innovation, problem-solving, and teamwork.

 

It was a great pleasure having you onboard. Thank you for all your great contributions and leadership Esteban!

 

Get in touch

If you wish to hear more about this project, please feel free to reach out on the links below.

Newcross Healthcare

Overview

Steven spent 18 months working as Lead Engineer for HFA team. “Uber for healthcare workers”. Processing payments for thousands of health workers in both home and residential care setting. Focused on performance and stability fixes, CICD pipelines, upskilling new engineers, removing blockers, backend deployments and troubleshooting/extending system.

Technology Stack

Express, FeathersJS, Kafka, Sequelize ORM, Promises, Asyc/Await, ES2021, RESTful APIs, Jest, React, Babel, Webpack, Redis, RabbitMQ, SQL Server, DB Replication, Bitbucket, Github Actions, Monorepos, Docker, Kubernetes, Test Automation, GitOps, DevOps, Jenkins, Bash, AWS, EC2, S3, SQS, Serverless, Lambdas, CloudFront, CloudFormation, SNS, IAM, Load Balancing, SonarQube, SSL/TLS Certificates, New Relic Analytics. OAuth, Single Sign-On. Performance optimization. Debugging Production. Code Reviews and mentoring.

Key Deliverables

Steven joined Newcross at a critical time of change. The initial intention was for him to continue the work of previous engineers in a small team maintaining a highly impactful healthcare platform that helped to improve people’s lives and was very much in demand. However it quickly became evident that the tech debt accumulated over years made the platform hard to maintain, let alone grow the business.

Steven went from being a Senior Engineer in a team of 2, to interviewing and leading a team of 10 engineers and testers. All the while helping to mentor and upskill new hires, removing blockers, automate deployments, track down issues in production, improve the platform to make sure it was performant and reliable, and being responsible for cross-functional collaboration.

Feedback

Here is feedback on Linkedin.

Working with Steven was great. He joined Newcross at a critical time and quickly became an essential part of the backend team. He then took charge of our platform backend and made significant contributions towards performance improvements, build automation, bug fixes and setting up a strong engineering practice within the team. He also helped in laying the foundations of migrating Monolith to Microservices. Very happy to recommend him.

 

LetMePark

Building smart cities by connecting vehicles with their environment.

Founding Engineer

Steven had a pivotal role designing and building the core platform infrastructure for this startup in the urban mobility space. Maximizing IT resource use and speed-to-market with low-cost, stable, high-performance infrastructure.

As the platform grew in complexity and demand, Steven became CTO in order to encompass the leadership of a growing technology team of engineers, designers and testers.

Backend Architecture & Integration

Integration with multiple third-party parking provider services, allowing real-time price and availability checks, bookings and automated parking notifications.

The skills used were: Google Cloud, Amazon Web Services, Build Automation, JavaScript, Node.js, API Development, MongoDB, DevOps, Docker, ECS, Gitlab, Security/Cryptography, Bash/Unix scripting, MQTT, Nginx, PCI Payment Processing (Paycomet TPV) and Test Automation.

Web & Mobile Hybrid App

Development and enhancements to a Vue.js (Nuxt) web app doubling up as a hybrid web-view app for iOS and Android platforms, allowing clients to carry their parking experience anywhere inside their pocket.

Voice Assistant Integration

Steven worked on integrating the Alexa Skill that allows users to search and book whilst driving their car.

This included providing all necessary backend APIs and authentication/user flows as well as the technology platform capable of live multi-provider search and bookings, including live monitoring.

Payment Processing

Steven also integrated the customer Credit Card capture and payment processing flows for both bookings and automated parkings.

Feedback

We were lucky to find Steven. He was able to work under time-pressure and with a constantly changing set of priorities to deliver much of the core IT infrastructure for our Mobility-based startup. Later growing in his role to encompass the leadership of a growing development team for our unique solution.

Apart from being disciplined, motivated and highly knowledgeable, he barely had much of an ego, always willing to help junior developers and ‘wear many hats’ as needed, explaining technical problems and opportunities in plain English to make sure that the leadership was informed at every step of the choices we had available to us.

SEEK Role Requirements

Full Stack JavaScript contract role working on SEEK User Interfaces and AWS hosted API’s.

Steven joined the ‘Role Requirements’ team to help deliver great candidate matching. Millions of job applications are now getting scored and ranked for role suitability every year, resulting in significant time savings to users of the SEEK platform.

The majority of the work involved various enhancements to the back-end capability in the form of AWS-hosted micro-service APIs, and some user interface updates to accommodate improvements to job-seeker and hirer experiences.

Working in a Continuosly Deployed, Agile environment with Node.Js, Angular, Knockout, Jasmine, Karma, Gulp, TeamCity, LESS, Microservices / APIs, PACT, Swagger, Golang, DynamoDB, C#, SQL Server, Docker, Serverless, SNS/SQS, Lambdas, AWS DevOps.