The next generation of our connected world calls for a low-latency, low-bandwidth, low-development-effort platform for synchronized interactions. The platform must also enforce privacy from the ground up, in particular in anticipation of an always-on Augmented Reality future.

In traditional synchronization approaches, computations are performed on a server and results are continuously distributed to clients. Croquet moves all computation to the clients. A lightweight “reflector” server directs the clients to advance time in sync, and ensures that any external event is incorporated by all clients at exactly the same point in the computation, leading to synchronized, bit-identical state. All data is end-to-end encrypted by the clients; the server stores and distributes data, but can never peek inside.

Croquet’s programming model separates the synchronized computation of “models” from individually computed “views”. This means the world is the same for everyone, but the display of the world can be tailored to each device and user. Models and views communicate using a publish/subscribe mechanism that routes certain events via the reflector. This model/view separation and pub/sub communication is a major departure from the previous, proxy-based Smalltalk implementation of Croquet. It retains the ability for live programming by atomically incorporating new code.

Vanessa is the chief architect of the current JavaScript-based implementation. She will give an overview of the system, highlight challenges in designing the API, and explore the far-reaching implications of the shift from server to client.

Vanessa is a co-founder of Croquet Corp and the principal engineer of the current Teatime client/server architecture underlying Croquet. She has been developing interactive systems for more than 20 years with a focus on live, self-supporting systems (including Squeak Etoys, Scratch, Lively, Smalltalk VMs).