AWS User Group UK Meetup #78

Welcome to our July event. We're delighted to welcome Guilherme Dalla Rosa, CTO, MerCloud and Matt Johnson, Principal Technologist, MongoDB

Here's what they're bringing:

Serverless makes scaling easy. Multi-tenancy makes it dangerous. Guilherme has built and operates a live B2B SaaS platform on exactly this architecture, where one misconfigured IAM policy can put one tenant's data in front of another. He has wired Amazon Cognito, Amazon DynamoDB, and AWS Lambda together to keep millions of tenant-partitioned records isolated under real production load. Tonight Guilherme is walking us through the IAM policy-based isolation patterns that actually hold up, and the deployment-model trade-offs behind them.

MongoDB Atlas isn't a database running on EC2. It's a hyperscale platform that MongoDB engineered on top of AWS. Matt works at the intersection of data, security, and cloud architecture, and he's here to open up how Atlas is actually provisioned and operated under the hood. Tonight Matt is giving us the engineering story: how MongoDB's own teams run Atlas on AWS, and how PrivateLink, KMS, IAM, and Marketplace are wired in to handle networking, security, and procurement.

A big thank you to our sponsors Cloudscaler, Rayo & The Scale Factory for making this event possible.

Programme:
18:00: Arrival, registration
18:15: Talks start
20:00: Networking with food and a drink provided by the generosity of our sponsors.

Talk 1:
Building Secure and Efficient SaaS Platforms on AWS Serverless with Guilherme Dalla Rosa

Let's go on a journey through the world of multi-tenant architectures on AWS using serverless technologies. In this talk, we will uncover the key aspects of multi-tenancy, including security, tenant isolation, and performance. We will learn how to utilise Cognito for authentication, DynamoDB to store millions of tenant-partitioned records and lambda for compute. We will also explore different deployment models and their tradeoffs, and, finally, we will learn how to implement policy-based isolation with IAM to keep our execution context tied to one specific tenant and avoid data leakage. By the end of this talk, you will feel more confident building SaaS applications on AWS with serverless technologies and you will have learned some of the many insights that come from the AWS Well-Architected SaaS Lens.

Learning Takeaways

• Implement IAM policy-based isolation to scope each Lambda execution context to a single tenant and prevent data leakage
• Evaluate pool, silo, and bridge deployment models - the cost, complexity, and isolation trade-offs of each
• Use Amazon Cognito and DynamoDB together for tenant-partitioned authentication and millions of tenant-scoped records at scale
• Apply AWS Well-Architected SaaS Lens patterns to make defensible, production-ready architectural decisions
• Automate tenant provisioning from the start - the patterns that work at five tenants break at fifty

Guilherme Dalla Rosa
Guilherme is a seasoned software engineer with extensive industry experience, having contributed to projects across Brazil, Ireland, and the UK. He currently serves as the CTO of MerCloud, a B2B e-commerce platform that streamlines the sales process for companies. In addition to his leadership role at MerCloud, Guilherme is also an AWS Community Builder, where he actively shares his expertise and passion for leveraging technology to help businesses enhance their processes and achieve their goals.

Talk 2:
MongoDB Atlas on AWS - A Deep Dive with Matt Johnson

MongoDB Atlas is more than a managed database service running on EC2. It is a cloud-native data platform engineered to take advantage of AWS infrastructure, automation, and security services so teams can build resilient, scalable applications without stitching the operational pieces together themselves.
In this deep dive for the AWS user group, we'll unpack how Atlas is deployed and operated on AWS: How our internal teams provision and manage Atlas and how AWS-native integrations such as PrivateLink, KMS, IAM, and Marketplace simplify networking, security, and procurement.

Learning Takeaways

• Understand how MongoDB's own teams provision and operate Atlas on AWS, not just how the service looks from a customer's seat.
• See how Atlas is engineered as a cloud-native platform, using AWS infrastructure and automation for resilience and scale that customers would otherwise build themselves.
• Learn how AWS-native integrations - PrivateLink, KMS, IAM and Marketplace - are wired in to handle networking, security and procurement under the hood.

Matt Johnson
Matt is a Principal Technologist at MongoDB with over 15 years of experience across cloud architecture, security, data platforms, and developer ecosystems. He specializes in helping organizations build secure, compliant, and scalable data and AI systems, with a focus on cloud resilience, AI governance, and data automation. Matt regularly speaks on the intersection of data, security, and AI, helping teams turn emerging technologies into trusted, production-ready solutions.

Do you have a story to share?
If you are interested in speaking at one of our events, please check out our call for papers.

We are advocates for greater inclusion & diversity in UK Tech and are especially keen to receive talk submissions from people in underrepresented groups. If you are interested in speaking at a future meetup but would like to discuss what to expect or need assistance, please contact our Inclusion & Diversity Lead Natalie Gray - graynataliej@gmail.com or DM her @natjgray

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