Scala eXchange 2015

Topics covered at #scalax

Thursday, 10th - Friday, 11th December at Business Design Centre, London

49 experts. will be speaking. Starts at 9:00 AM.

Want to hear the latest happenings in the world in Scala? Interested in hearing how your peers are approaching similar software challenges? Then join us at Scala eXchange 2015, Europe's largest community conference on Scala.

Thank you!!!

Thank you for joining us at Scala eXchange 2015! We had a terrific time, we hope you did too! A massive thanks to our great programme committee, all speakers, sponsors and to everyone who joined us this year!

Thanks also to all those who joined us at the ScalaXHack at CodeNode, helping to make the language and documentation better!

Registration for 2016 is open!

Scala eXchange 2016 will be held on Dec 8th and 9th at the Business Design Centre. Registration is already open - don't miss the early bird offers!!

Help us create another great conference next year!

All Skills Matter conferences are created for and by the community. We would love to have your input and ideas on how next year should look like. If you like to help us this way, please contribute to our Call For Thoughts!

Follow us at #ScalaX to hear all the latest news.

What happened at ScalaX London 2015?

Speakers & Program

ScalaX 2015 was crafted for and by the community and this year is no exception! We received lots of ideas, talks and feedback from our community this year, resulting in a program packed with talks and workshops on Scala, functional and reactive programming, data science and the Typesafe stack. Find the full line-up here.

The Venue

The BDC has been home to the Scala eXchange for several years now, offering a fantastic sizeable space to learn, share and collaborate. Find more details about the venue here.

Registration for ScalaX 2016 now open!

Fancy joining 1,000 fellow Scala developers, architects and data scientists for 3 days of learning and sharing skills? We expect to sell out this year, so if you fancy coming along, best to get your skates on and book your 2016 early bird ticket today! Register here.

Follow us at #scalax for the latest news!

Day 1: Day 1

Thursday 10th December

Track Room 1 Room 2 Room 3 Room 4

Breakfast and Registration


Opening and Welcome to Scala eXchange 2015


Keynote: Scaling Intelligence: moving ideas forward

Jessica Kerr

scalability scala scalax

Coffee & Tea


Functional Patterns for FP beginners

Clément Delafargue

functional scala fp typeclasses

Akka Cluster on CoreOS

Heiko Seeberger

akka-cluster akka coreos

A deep dive into scalac

Chris Birchall

scala cake-pattern scalac typeclasses java-bytecodecomplication

Count-Min Sketch in Real Data Applications

Laura Bledaite

scala twitter mapreduce query-answering bloom-filter hyperloglog count-min-sketch algebird summingbird

Coffee & Tea


Building a CQRS application using the Scala Type System and Akka

Renato Cavalcanti

cqrs akka event-sourcing streaming ddd akka-persistence EventSourcing akka-persistence-query

What are typeclasses and why you should care

Philip Wills

scala typeclasses

Introduction to Apache Spark

Deenar Toraskar

Spark hadoop scala

Towards Finagle at ING Bank

Alessandro Vermeulen

finagle api scala jms Enterprise-Scale Micro-service-architecture Reactive-Stack Ribbon



Keynote: Without Resilience, Nothing Else Matters

Jonas Bonér

scala scalax

Coffee & Tea


A purely functional approach to building large applications

Noel Markham

functional monads scala scalaz scalacheck imperative reader

Go distributed (and scale out) with Actors and Akka Clustering

Patrick Di Loreto

akka-cluster scala actors omnia

Combining batch and stream analytics with Apache Spark and Apache Cassandra

Christopher Batey

scala apache-spark Apache-Cassandra batch-analytics stream-analytics

Ammonite: rock-solid shell scripting in Scala

Li Haoyi

java scala bash ammonite

Coffee & Tea


Distributed Real-Time Stream Processing: Why and How

Petr Zapletal

Exploiting Dependent Types for Safer, Faster Code

Jon Pretty

scala typesafe dependent-types

Time travelling in distributed software systems

Bogdan Roman

scala akka event-sourcing cors akka-persistence ES command-query-responsibility-segregation typesafe-platform Akka-clustering

Optimising Scala for fun and profit

Rory Graves

functional-programming scala

Coffee & Tea


Lightning Talks 4

Marconi Lanna, Nicolas Long, Sofia Cole, and Rafal Gancarz

functional-programming scala

Lightning Talks 2

Karl Brodowsky, Aurelien Waite, Jeff Smith, and Bas Geerdink

scala scalax computers

Lightning Talks 1

Jamie Pullar, Mikael Valot, Nick Pollard, and Andrew Gustafson

scala types json typeclass shapeless fix-protocol flexible-data Protobuf library-strucs

Lightning Talks 3

Rory Graves, Sue Carter, Krzysztof Otrebski, and Willem Meints

scalax freeslick

Scala eXchange Party @ CodeNode until late - Routemasters Buses will take you to CodeNode!

Day 2: Day 2

Friday 11th December

Track Room 1 Room 2 Room 3 Room 4 Room 5 Room 6

Breakfast and Registration


Keynote: Spark+Hadoop and how it relates to Scala

Sean Owen

Spark hadoop scala

Coffee & Tea


Reactive in practice: web services with Scala and AWS

Matt Roberts

reactive scala slick aws restful akka-http

Streams: reactive? functional? Or: akka- & scalaz- streams side-by-side

Adam Warski

streams reactive functional live-coding akka-streams scalaz-streams single-node-stream-processing compositionality FP-library

Distributed deep learning

Jan Machacek

akka-cluster akka-persistence apache-spark Muvr-project scala-eXchange-2014 IoT/wearables

Scala and Akka and Docker, oh my!

Mario Camou

IoT scala akka

Coffee & Tea


Fast automatic type class derivation with shapeless

Alexandre Archambault

oop shapeless type-level-programming case-classes ADT

'Inappropriate' applications for Scala

Danielle Ashley

functional scala types inappropriate game-boy MP3-decoder

Finch: Your REST API as a Monad

Vladimir Kostyukov

finagle api monad finch REST-API functional-library

Distributed Data Science with Scala in a Browser

Xavier Tordoir

scala machine-learning distributed-data-science spark-notebook



Keynote: Typelevel - the benefits of collaboration

Miles Sabin

scala shapeless scalacheck scalax scala-cats

Morgan Stanley Raffle + Coffee & Tea


Workshop: Shapeless for Mortals

Sam Halliday

scala json shapeless clean-code efficient

Workshop: End-to-end asynchronous back-pressure with Akka Streams

Konrad Malawski

streams reactive reactive-streams end-to-end asynchronous-back-pressure akka-streams

Workshop: Mind blown: Crafting a Distributed Data Science Pipeline using Spark, Cassandra, Akka and the Spark Notebook

Andy Petrella and Xavier Tordoir

Spark scala akka cassandra spark-notebook

Workshop: Introduction to property based testing

Mark Harris

ScalaCheck-library property-based-testing property-test

Workshop: Building Interpreters in Scala

Noel Welsh

scala twitter interpreters doodle stitch

Workshop: Essential Slick: Hands On With Slick 3

Dave Gurnell

action-monad scala dsl typesafe sql slick cake-pattern slick-3

Scala eXchange 2015 Wrap Up

Debugging implicits

25 March 2015 / Piotr Kukiełka

I’ve been recently asked what are my favorite and least favorite Scala features. Probably few options would be matching here, but I decided to give one answer for both questions: implicits. Why? Implicits are very simple and yet very powerful concept but with great power comes great responsibility. They can be used for implicit parameters, implicit conversions, view bonds and context bounds (type classes) letting us solve couple of different problems with one language feature. But at the same time we must be aware in what context we are using them and – which is much harder – which implicits are available in the current context.

Luckily we are not left alone with that problem. Main Scala IDEs like ScalaIDE or IntelliJ are able to list currently used implicits and we can do the same in REPL as

Let’s go through basic example with Ordering type class to check how things work together and what to do in case you are stuck. First, let’s create simple class wrapper around Int value and make array of its elements:

case class IntWrapper(n: Int)
val list = Array(IntWrapper(2), IntWrapper(7), IntWrapper(3))

Now we want to sort our list using one of the methods from the standard library. We can do this using sortBy, sortWith, or sorted. We will use sorted:

scala> list.sorted
:11: error: No implicit Ordering defined for IntWrapper.

Read the full article here.

Scala at Morgan Stanley

Morgan Stanley are excited to be sponsoring ScalaX this year and ahead of the conference we have created a short video outlining “Scala at Morgan Stanley”. Please come and meet some of our engineers at the stand over the course of the conference. We’d love to meet you and talk about all the exciting initiatives we are doing in Scala.

You can download the video here.

Business Design Centre

In it's 5th year, the Scala eXchange has been growing and growing both in size and in depth. First held at Skills Matter's own premises, the conference now requires a large venue, equipped to accommodate the sizeable community of attendees, sponsors and speakers it attracts, so last year, we found it a new permanent home (for a while anyway): the Business Design Centre in Angel. With a fantastic keynote space, four additional lecture & workshop theatres and a terrific break-out space, we couldn't think of a better place for ScalaX! We hope you'll agree and enjoy all the great amenities the BDC has to offer.

Situated in Islington, one of London’s most vibrant areas, the BDC is within walking distance of Angel tube station and relatively close to Kings Cross, Farringdon, Liverpool Street and Euston stations. Conveniently located outside the congestion charge zone, the venue also benefits from on-site car parking, an adjacent Hilton Hotel, and has disabled access.


Business Design Centre

52 Upper Street, Islington, London, N1 0QH, GB

View details, travel and nearby hotels

We very much look forward to celebrating Scala and it's terrific ecosystem of technologies and people this year! If you do too, you may like to get involved with the community or conference. Here's some ideas.

Looking forward to it? Share it!

Are you looking forward to the conference? We'd love to hear what you are most keen on, or are hoping for on twitter or google+.

Would you like to help us run #ScalaX?

If you would like to help the Skills Matter team organise a great ScalaX conference at the BDC this year and get a free conference ticket in return, we'd love to hear from you.

Each year, the ScalaX benefits from the support of up to 20 volunteers in our community, who help us with the set-up of the conference, the welcoming of attendees, speakers and sponsors, the facilitation of Q&A sessions and other helpful things. All volunteers receive a free ticket to the conference and we normally ask for your help for a full day prior to the conference plus one of the mornings of ScalaX. If you would like to volunteer (and get a free #ScalaX ticket in exchange for your support), please complete the ScalaX Volunteer form and we'll be in touch shortly to let you know if you have been selected.

Community blogs

Scala eXchange Party

December 10th

Scala eXchange 2015 continues at Skills Matter's new home CodeNode for the Scala eXchange Party! Starting at 6.30pm on 10th December 2015!

Availability is limited - buy your tickets now and avoid disappointment!


December 12th

We're excited to announce the first ever Scala Exchange Hack Day, to be held on Saturday 12th December at CodeNode in partnership with Underscore and the London Scala User Group.

Register online.

Stairway to Scala (Advanced Workshop)

December 7th-9th

Want to learn the advanced aspects of the Scala language and core libraries? Want to find out more about ScalaTest, profiling and best practices from the best in the business? Then come along to this very special Tutorial delivered by Dick Wall and Bill Venners to hone your skills!

Space limited. Book today!

Available Packages

    • Engage with the Scala community! Show off your team, projects, tools or devices at your #scalaX conference booth!

      Brand Visibility Benefits
      • Your logo (large) on the Scala eXchange web pages
      • Your own dedicated partner page on
      • Your logo (large) on all in-venue conference banners
      • Visibility of your brand and your support for the Scala eXchange in regular social media updates.
      Engagement Benefits
      • Large booth area in #ScalaX's exhibition space (6mx3m / 18 sqm / 194 sqft).
      • An article and or video about your team's Scala projects and experience featured on the ScalaX 2015 pages.
      • Your sponsored message with hot linked logo in the Scala eXchange post-conference newsletter
      • Two items (leaflet, device, pen or notepad) included in all the Scala eXchange swag bags
      • 5 free exhibitor tickets for ScalaX exhibitor team
      • 5 free full conference tickets, which you can gift to your clients, your engineering team or members of Computing At School (teachers learning computing to teach the new National Computing Curriculum).
      • 20% discount off any additional conference tickets.
    • Brand Visibility Benefits
      • Your logo (medium) on the Scala eXchange web pages
      • Your own dedicated partner page on
      • Your logo (medium) on all in-venue conference banners
      • Visibility of your brand and your support for the Scala eXchange in regular social media updates.
      Engagement Benefits
      • A booth in the exhibitors space (1.8m x 0.6m / 180cm x 60cm)
      • Your sponsored message with hot linked logo in the the Scala eXchange post-conference newsletter
      • One item (leaflet, device, pen or notepad) included in 600 Scala eXchange swag bags
      • 3 free exhibitor tickets for your #ScalaX exhibitor team
      • 3 free full conference tickets, which you can gift to your clients, your engineering team or members of Computing At School (teachers learning computing to teach the UK's new National Computing Curriculum).
      • 10% discount off any additional conference tickets.
    • Brand Visibility Benefits
      • Your logo (small) on the Scala eXchange web pages
      • Your own dedicated partner page on
      • Your logo (small) on all in-venue conference banners

    • Be remembered! Have your logo printed on the Scala eXchange t-shirts, provided to all conference attendees, speakers and sponsors attending this year.

      Brand Visibility Benefits
      • Your logo on all Scala eXchange t-shirts
      • Exclusive to two t-shirt sponsors only!
    • Be remembered by all conference attendees, speakers and sponsors attending the party this year! Have your logo printed on the Scala eXchange 2015 Party beer mats and on highly visible party posters and pop-up banners, which are bound to feature in lots of pictures this year.

      Brand Visibility Benefits
      • Your logo displayed on the #ScalaX 2015 party beer mats and on the party table pop-up banners;
      • Five free tickets to the #ScalaX 2015 Party, which you can gift to your clients and team members;
      • Your logo (small) on all in-venue conference banners and on the #ScalaX 2015 Sponsor web pages;
      • Your own dedicated partner page on;
      • Exclusive to two party sponsors only!
    • Be remembered! Have your logo printed on the #scalaX 2015 swag bags, provided to all conference attendees, speakers and sponsors attending this year.

      Brand Visibility Benefits
      • Your logo on all Scala eXchange 2015 swag bags
      • Exclusive to two swag bag sponsors only!

To discuss sponsorship opportunities please contact the team: