About Reuben
If an aging .NET system runs your business and nobody dares touch it, that's exactly the problem I solve.
I spent 15 years building and modernising systems where mistakes genuinely weren't an option: settlement platforms at Citi processing billions a day, treasury systems at Bank of America. That background taught me a way of working I now bring to smaller companies: understand the system before changing it, migrate in safe steps, test everything, keep you informed early, often and in plain language.
A few things I've done for clients like you:
• Built REST APIs and integrations that link systems securely.
• Re-architected platforms that couldn't handle growth to process orders of magnitude more volume.
• Modernised aging stacks (ASP.NET Framework to .NET Core/8, on to Azure) so development teams can move quickly again.
• Worked with teams to implement testing and CI/CD pipelines that make releases and versioning almost boring.
Whatever the problem, every change I make answers the same questions before it ships: how will it be tested, how will it be migrated, how do we roll back, and what's the smallest version that proves it works. The result: a system that stops being the constraint on your business.
Based in Madrid, available now, remote or on-site across Spain. Let's talk about your system and what it's holding back.
English
Native or bilingual
Japanese
Conversational
Spanish
Basic
Can work on-site
Madrid (up to 50km)
Experience
- Salmon Treasury,Dev Ops Lead - Treasury TechnologySOFTWARE PUBLISHINGJanuary 2024 - October 2025 (1 year and 9 months)Dublin, IrelandSole DevOps lead supporting four product teams (~23 engineers), introducing CI/CD, infrastructure-as-code and engineering governance from scratch for a treasury platform serving 40+ Tier 1/2 enterprise clients; partnered directly with the CTO on architecture across identity, infrastructure and deployment.• • Designed and built RESTful APIs as TypeScript Azure Functions (secured with API keys) integrating Azure DevOps webhooks with external tooling, enabling end-to-end build and deployment status reporting.• • Cut release cadence from quarterly to biweekly with automated, deterministically versioned build pipelines and full commit traceability across 40+ client deliveries.• • Provisioned Azure SaaS environments with Terraform (Container Instances, SQL Managed Instances, Web Apps, Key Vault), embedding identity and access controls from the infrastructure layer using Azure IAM and Managed Identities.• • Championed GitFlow, semantic versioning and Azure DevOps governance; automated repeatable test-environment restore using Terraform, Azure CLI and PowerShell.
- Citi,Senior Developer - Custody TechnologyBANKING AND INSURANCEJuly 2021 - January 2024 (2 years and 6 months)Dublin, IrelandFull stack developer on a globally distributed team responsible for settlements routing and trade capture, processing billions in daily dollar value across the Swift network. Delivered multiple Tier 1 projects under rigorous regulatory deadlines.• • Built a high-value transaction oversight control end-to-end (ASP.NET, .NET Framework, T-SQL), reducing financial risk and meeting regulatory standards; delivered via Git, Jenkins and uDeploy CI/CD.• • Re-engineered JASDEC SWIFT batch processing for a 10x throughput gain (most trades completing in under 3 minutes) using the dispatcher pattern, T-SQL optimisation and .NET Core 6.0.• • Engineered MT54x forex processing enhancements for sub-custodians (.NET Framework 4.8, T-SQL) on a high visibility Tier 1 application.• • Automated SQL Server schema deployments via a custom .NET 6.0 CLI tool, containerised with Docker and integrated into the CI/CD workflow.
- Bank of America Merrill Lynch,VP - Strategic Asset Liability TechnologyBANKING AND INSURANCEOctober 2015 - July 2021 (5 years and 9 months)Dublin, IrelandSenior full stack engineer for the bank's Treasury Strategic Asset Liability application, collaborating with a dynamic, cross functional team spanning Ireland, the US, and the UK.• • Built the backend for real-time intraday gross settlement using a distributed microservices architecture (Akka.NET, .NET Framework 4.8, T-SQL, ADO.NET), improving decision-making for treasurers and fund managers.• • Delivered SQL-driven treasury balance reporting (Angular front end, T-SQL backend) meeting intraday and end-of-day regulatory matching requirements.• • Provisioned a secure, RBAC-enabled Kafka cluster with Active Directory integration, TLS and automated Ansible deployment to RHEL servers.• • Led migrations from on-prem TFS to Azure DevOps and on to an enterprise CI/CD pipeline; mentored the team on GitFlow, build/test/static-analysis/packaging and deployment automation.
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Education
- Microsoft Certified: Azure Developer Associate2023Microsoft Certified: Azure Developer Associate
- Microsoft Certified: Azure FundamentalsMicrosoft Certified: Azure Fundamentals