Open Collective
Open Collective

Bartosz Sypytkowski

OSS contributor



Transparent and open finances.

View all expenses  →
-$3,550.00 USD
Invoice #136812
-$3,750.00 USD
Invoice #130799
-$3,900.00 USD
Invoice #121440
↑ Total contributed

--.-- USD

↓ Total received with expenses

$81,643.00 USD


Since 2014 core team member of Akka.NET project: port of the JVM toolkit and runtime for building resilient, concurrent and distributed applications based on actor programming model. During that time contributing in:

  • Building framework (Akka.Streams) used as reactive streams standard implementation. This included building engine for self-optimizing workflow based on customized free-monad / interpreter pattern and remote availability layer (StreamRefs).
  • Building and optimizing eventsourcing engine used for actor persistence and it's integration with Akka.Streams. Also support for multiple persistence providers, mostly SQL engines. Optimizing existing engine for building socket servers on top of an actor layer and integration with Akka.Streams.
  • Building distributed pub/sub mechanism over Akka cluster (read more)
  • Building virtual actor library (Akka.Cluster.Sharding) for creating automatically managed and rebalanced distributed actor runtime. Also wrote several articles about it: 1 and 2.
  • Building state-based Conflict-free Replicated Data Types (CRDT) library on top of akka cluster. Later optimizing it for delta-state based implementation.
  • Implementing an Akka.NET F# wrapper library called Akkling.
  • Minor libraries for working with Akka.NET.

Another big project of mine was FSharp.Data.GraphQL - an F# implementation of a Facebook's GraphQL standard - where I was responsible for building and optimizing a server-side implementation of it. Related lecture: