Presentations should always work offline – especially in online conferences

We just finished the WeAreDevelopers World Congress 2025 in Berlin, and I am still recovering from the event. It was a fantastic experience, and I am grateful to everyone who attended and made it a success. As the main moderator of the main stage, I had the pleasure of introducing many amazing speakers and topics. I also had a great experience with the stage crew, who did a tremendous job getting all speakers set up, mic-ed up and ready to rock. However, we also had quite a few hiccups and live demos not working and the reason is always the same: presenters assume that there will be a fast and stable connection at events, which is never the case.

I’ve written about this in more detail in the Developer Advocacy Handbook more than a decade ago, but things have not changed much. Sure, events spend an amazing amount of money and effort on connectivity, but with tons of people at the event all connected, official streaming and a whole bunch of influencers being online all the time, any network can have its outages. So here is a piece of advice that helped me tons during my career as a presenter, trainer and moderator: do not rely on connectivity but make sure your presentation material works offline.

Now, almost every presentation tool these days is cloud-first. Google Slides, PowerPoint, millions of “best powerpoint alternatives”, all are available in the browser and on-line. Which is great as it allows for collaboration without having to sync a file of several dozen megabytes. The main slides are OK to depend on a connection, but it gets tricky when you embed video, fonts, demo code and images not as part of the presentation but as an online dependency.

Videos embedded in your slides that are hosted on, for example, YouTube are a terrible idea because:

• They need to get loaded and rely on a stable stream.
• Third party media can not autoplay because of security reasons – this means that if you use a clicker in PowerPoint and in Google slides you need to show the controls and click the play button by hand.
• The embedded video gets loaded from the presentation device, meaning that there is always a delay.
• If you present at an online conference in a streaming service, this means your connectivity goes down and the quality of your main feed suffers.

So, for the sake of the mental state of stage crew, moderators and all that support you as a presenter: make your slides work offline. If you present from the stage machine, have it on a memory stick and prepare fonts you use to install. If you present on your own computer, have all you need on your own device and turn off any syncing to Clouds (Apple Cloud, Google Drive, OneDrive, DropBox…) before you start presenting.

Personally, I use PowerPoint and download videos to embed using yt-dlp or Downie.

Public speaking is stressful as it is, don’t make it harder on yourself by relying on tech that may not be available.