Combine with John Sundell training

Join John Sundell, creator of Swift by Sundell, for a full day of training on Apple’s Combine framework.

Learn the fundamentals of Combine and the reactive programming paradigm. See how to create ever-more-advanced data pipelines, how to perform routine tasks such as data store operations or network calls, and how to design and test Combine-based code.

The goal of this workshop is to prepare you for utilizing Combine to create apps on iOS and other Apple platforms. It is mainly targeted at developers with little or no experience of Combine or other reactive programming frameworks (including ReactiveCocoa and RxSwifft), and will cover both fundamentals and advanced concepts.

If you like the website, podcast or videos from Swift by Sundell, you’ll love this workshop!

Every update and improvement to Combine that will be announced at WWDC will be included in this training.

This training is organized by Swift Paris Trainings (aka Greg Lhotellier) in partnership with Delicious Insights.

  • World-renowned expert trainer
  • Multiple hands-on projects
  • State-of-the-art tech
  • Latest best practices


The Combine with John Sundell workshop empowers trainees to:

  • Become familiar with the various APIs and operators in Combine.
  • Learn core principles for creating Combine pipelines, focusing on iOS-specific use cases.
  • Understand how Combine can be utilized to solve common asynchronous needs such as writing concurrent code, orchestrating data store operations, observing events or performing network calls.
  • Explore various architectural patterns for creating robust data flows with Combine.


  1. Introduction to reactive programming

    • Fundamentals
    • Asynchrony
    • Publish/Subscribe model
    • Processing operators
  2. Overview of the Combine API

    • Publishers & Subscribers
    • Subjects
    • Operators
  3. Data pipelines

    • Principles
    • Chaining operators
    • Best practices
  4. Traditional code vs. Combine

    • Differences with closure-based code
    • Refactoring legacy code using Combine
  5. Debugging and testing

    • Debugging a Combine pipeline
    • Unit-testing Combine code
    • Best practices
  6. Side effects

    • Fundamentals
    • Caching
    • Working with data stores
  7. Using Combine in an application

    • Integrating Combine with UIKit and SwiftUI
    • ObservableObject
    • @Published properties
    • Publishers found in Foundation
  8. Parallelizing

    • Not just through asynchrony
    • Using multi-thread code with Combine
  9. Beyond publishers

    • Connecting and merging Combine publishers
    • Writing a custom Combine publisher

Next sessions

    (Unless otherwise stated, every session has 4+ seats still available, and is in French; you can naturally book custom dates for your company using the link further below.)


    You registerPer trainee
    1 to 2 trainees€900 net
    3 to 4 trainees€750 net
    5+ trainees€600 net

    Intended audience and pre-requisites

    The training takes place entirely in English, so a sufficient spoken understanding of English is mandatory.

    Trainees must also have sufficient experience in developing iOS apps with Swift and SwiftUI or UIKit, and basic proficiency with Git and command-line tools. We emphasize that this training is not intended for beginners, but targeted at people with prior professional experience of app development with Swift on iOS. It is also not the best fit for people with lots of experience writing RxSwift or ReactiveCocoa code, as a significant share of the training will cover similar reactive programming concepts.

    Trainees must bring a Macbook capable of running Apple's developer tools with reasonable performance, and have the latest non-beta Xcode installed.

    Unless otherwise specified, predefined-dates, multi-client sessions are held in French, so attendees should be reasonably fluent. You are naturally welcome to book custom dates for your company using the link above.


    When the training starts, trainees receive all the related slides and supporting material in a web-based format, so they can easily follow along.

    Once the training is done, they also get an extremely content-rich debrief e-mail, a reference archive with all finalized codebases (fully annotated and tested), all related slides and various complementary resources.


    • Sessions run 7hr a day, or 4hr12 a half-day, adding up to 14hr, 21hr or 28hr.
    • Full days run from 9:30 to 12:30 and 14:00 to 18:00, half-days run from 13:48 to 18:00.
    • (For or U.S. friends, that's 9:30a-12:30p / 2p-6p and 1:38p-6p Paris time, respectively.)
    • For custom dates booked specifically by your company, the schedule can be adjusted to better suit your needs. In particular, we can use half-days locked on reasonable hours in your timezone, e.g. 9a-12:30p EST or 8a-11:30a PST.
    • Every trainee uses their own laptop or workstation.
    • The laptop brought by the trainee must be a Macbook capable of running Apple's developer tools with reasonable performance, and have the latest non-beta Xcode installed.

    • Training sessions range from 5 to 10 trainees.

    You can find all the details and modalities of registration, payment, cancellation and refunding in our Terms of Sale, along with our Conduct Policy.


    John Sundell

    John Sundell

    John Sundell is the creator of Swift by Sundell. During the past three years, he’s helped over a million developers level up their skills through over 300 freely available articles and podcast episodes, and by speaking at top tech conferences around the world.

    With over a decade of professional software development experience, working for companies like Volvo and Spotify — he’s now working with several teams of various sizes, to help them improve their skills, their code, and the products that they ship.

    His goal is always to help the Swift and iOS developer communities as much as he can, to share his experiences working on all sorts of apps and software products, and to help others get more out of their work as software developers.


    • Whether you’re discovering reactive programming or seeking to boost your Combine skills, this training is top-notch, works for trainees of all skill levels and benefits from one of the best content creators for iOS devs right now: John Sundell.

      David Yang – InsideApp