MongoDB .local Stockholm
From Hours to Milliseconds
Why Great Experiences Run on Live Data
01
Why Latency Matters
86,400,000 ms
The gap between batch and real-time
Most enterprise data pipelines still rely on batch ETL — extract overnight, transform in the morning, load by lunch. For internal dashboards that cadence is fine. But the moment that same data powers a customer-facing experience, the gap between “fresh enough” and “stale” becomes the gap between conversion and abandonment.
The latency spectrum runs from hours (classic batch) through minutes (micro-batch) to true milliseconds (stream processing). Each step down that spectrum unlocks new categories of experience: real-time recommendations, fraud detection before a transaction settles, pricing that reflects the market right now rather than the market at last night’s close.
Personalisation
< 200 ms
Risk & Fraud Checks
1–2 s
Operational Dashboards
< 15 s
Strategic Analytics
min–hours
When everything runs at batch speed, the consequences compound. Personalisation can’t adapt, fraud slips through, and dashboards only ever show you the past. The entire stack converges on the latency of the slowest system.
Personalisation feels generic
Dashboards tell you what already happened
Fraud is caught too late
Experiences feel disconnected
Research consistently shows that every 100ms of added latency costs measurable conversion. The question is not whether low latency matters — it’s whether your architecture can deliver it without a full rewrite.
02
The Live Data Plane
The shift from batch to live is not about replacing your data warehouse. It’s about adding an operational data plane that sits between your systems of record and your systems of engagement. MongoDB Atlas, combined with Atlas Stream Processing, acts as that plane — ingesting change streams, applying windowed transformations, and materializing results into collections that your application reads with single-digit-millisecond latency.
Systems of Record
CDC
Stream Processing
Materialized Views
Application
Systems of Record
CDC
Stream Processing
Materialized Views
Application
Atlas Stream Processing lets you define continuous queries over change streams using a familiar aggregation pipeline syntax. You don’t need a separate streaming platform or a new query language. The data stays within the MongoDB ecosystem, and the output lands in collections your application already knows how to read.
The result is an architecture where the operational database is not just a persistence layer — it becomes the live data plane that powers every downstream experience, from search to personalisation to AI inference.
03
Patterns You Can Apply
Three patterns emerged repeatedly across the use cases we explored in Stockholm. Each one is independently valuable and can be adopted incrementally — you don’t need to rebuild your stack to start seeing results.
Forward Cache
< 10 ms readsProject system-of-record data into MongoDB via CDC, creating a resilient read cache that serves traffic even when upstream systems are unavailable.
Real-Time Feature Store
< 50 ms featuresStream user behaviour events, compute rolling aggregates via Atlas Stream Processing, and serve feature vectors directly to recommendation engines.
Live Data Toolbox
ms–s configurableA composable set of building blocks — change streams, triggers, and stream processing pipelines — assembled to fit your specific latency requirements.
04
The Future: AI & Autonomy
Every serious AI deployment eventually hits the same wall: the model is only as good as the data it can access at inference time. Retrieval-augmented generation, real-time scoring, and agentic workflows all demand a data plane that returns results in milliseconds, not minutes.
The live data plane we built throughout this talk is exactly that foundation. When your operational database already serves fresh, pre-computed features alongside vector embeddings, adding an AI layer becomes an incremental step rather than a separate infrastructure project.
The practical advice: start small.
Pick one experience
Move it from batch to live
Measure, then expand