Technical architecture

SnowPlow has a very different architecture from conventional open-source web analytics packages such as Piwik piwik or [Open Web Analytics] owa. Where those packages are built on a tightly-coupled LAMP stack, SnowPlow has a polyglot, loosely-coupled architecture, involving:

• A JavaScript event tracker
• A CDN (Amazon CloudFront)
• An immutable flatfile-based data store (Amazon S3)
• JVM-based "big data" storage and querying tools (Apache Hadoop and Hive).

In the rest of this page we explain our rationale for this architecture, map out the technical components and finally flag up the benefits and limitations of this architecture.

Rationale for architecture

SnowPlow's distinctive architecture has been informed by a set of key design principles:

1. SnowPlow should be able to scale to tracking billions of customer events without crippling either a) the in-client tracking or b) the subsequent analysis of those events
2. Events should be stored in a simple, immutable data store - there should be no costly "updates in place" and it should be easy to join the SnowPlow event data to other data sources (e.g. demographic, CRM, e-commerce transactional or geographic)
3. SnowPlow should make it easy for business analysts, data scientists and engineers to query and analyse its event data in as wide a range of analytical tools (e.g. Hive, R, Cascalog, Sky EQL) as possible

Architectural diagram

The current technical architecture for SnowPlow looks like this:

![SnowPlow Technical Architecture] tech-architecture

Technical benefits

This section to come.

Technical limitations

This section to come.