PocketBytes - Firing AWS Firehose: Moving to a Stateful Lambda

Join us for an expert case study on how to. replace AWS Firehose, a Managed Cloud Service, with a Stateful Lambda (Without Losing a Record)

Location: In The Pocket Bucharest - Tudor Arghezi 21, H building, 4th floor

What we'll discuss:
Managed services are convenient until the bill arrives. In this case study, we replaced AWS Kinesis Firehose with a purpose-built serverless consumer for a client streaming millions of IoT records per minute into their datalake — taking on full ownership of batching, buffering, file layout, and durability in exchange for a fraction of the cost.

The catch? We built it on AWS Lambda, which is stateless by design. We'll walk through how we made it stateful using Kinesis tumbling windows, how an S3 multipart-upload state machine is carried across invocations, the retry semantics that guarantee zero data loss, and the trade-offs we deliberately made — including the ones where doing the "right" thing would have quietly made things worse.

If you've ever wondered what's actually happening inside a managed streaming service, or what it takes to build one yourself, this one's for you.

Agenda:

• 18:30 - 19:00 - Welcome
• 19:00 - 19:05 - In The Pocket Intro by Adrian Petrescu
• 19:05 - 20:00 - Firing AWS Firehose: Moving to a Stateful Lambda by Alexandru Gheorghita

Alex is a passionate Software Engineer specializing in Cloud and AI Engineering. With a strong foundation in designing scalable cloud architectures using AWS and Terraform, alongside full-stack development in Go, Python, and TypeScript, he thrives on turning complex technical challenges into intelligent solutions. Beyond the code, he is deeply committed to the tech community - whether mentoring students, leading technical workshops, or championing a culture of continuous learning and knowledge-sharing.

• 20:00 - 22:00 - Networking

Confirmation of participation:
This event is limited to 30 attendees to ensure high-quality discussions and meaningful connections. Spots will be reserved in the order we receive registrations. We’ll reach out one day before the event to confirm your attendance. In the absence of your confirmation, your seat will be allocated to the next person on the waiting list. Thank you for helping us make this a great experience for everyone!