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Case Study: Building a secure EU hosted multi-agent finance assistant on AWS
Cloud Combinator worked with a UK fintech platform to take their early "virtual CFO" idea and turn it into something real. The goal was a governed, production-ready proof of concept built on Amazon Bedrock.
The client wanted their users to be able to do things like create spending categories or set financial rules just by typing a request in plain English. But this is finance, so every action needed to be previewed, confirmed, and fully logged. It also had to be hosted in the EU and built to the security standards you'd expect in financial services.
The solution uses a supervisor agent that understands what the user is asking and routes it to the right specialist agent. Each agent handles a specific task, validates the request against an OpenAPI contract, and executes it through AWS Lambda. Before anything is written, the user sees a preview of exactly what will change. Every step is traced through CloudWatch.
On the security side, nothing was left to chance. Lambda functions run in private subnets with no inbound access. Each agent has its own tightly scoped IAM role. All data is encrypted with KMS and Bedrock's guardrails are tuned specifically for finance and PII handling. The whole thing is deployed in eu-west-2 London using Terraform.
What makes the architecture interesting is that it's built to grow. The same pattern of agent to OpenAPI to Lambda to data works just as well for reconciliation, anomaly detection, or enrichment. It gives the client a clear blueprint to scale from rather than something they'll need to rebuild later.