SharePoint Hackathon 2026 - Transmittal Flow

During the SharePoint Hackathon 2026, we showed a demo called Transmittal Flow. It’s a document transmittal solution built on SharePoint Embedded. The goal is pretty simple: make it easier to share files with external people without giving them access to a SharePoint site, without losing control. This matters because in a lot of industries, sharing documents isn’t just “send a link and done.” There are rules. There are approvals. And there’s always the question of who agreed to what, and when.

Transmittal Flow

TransmittalFlow bridges internal SharePoint project sites with external stakeholders using SharePoint Embedded as the secure document handoff layer.

• A SPFx Command Set extension lets project staff select documents and trigger a transmittal in one click SharePoint Embedded automatically provisions an isolated File Storage Container per client, copies the selected files.
• External reviewers receive a branded portal link (no Microsoft 365 account required) where they can read the AI summary, co-author documents in Office Online, and formally approve or reject the transmittal.
• Optionally can be configured to only allow invited users, or to allow anyone with the link to access the portal. The dashboard tracks all interactions, providing a clear audit trail of who accessed what and when.

At the core, Transmittal Flow acts like a client portal. A client can sign in and access the files you’ve shared with them. If you want, they can view or even co-author documents directly in SharePoint. That’s the basic part. But the interesting bit starts when decisions are involved.

A client can review a transmittal and explicitly agree or disagree. Instead of an email reply like “looks good,” they click approve or reject. That action is tracked. It’s clear. And it’s hard to misinterpret.

And since it’s built on SharePoint Embedded, you don’t have to worry about giving external users access to your internal sites. They only see what you share with them.

Demo time

So, when does this make sense?

It depends; If you’re in an environment with external clients, formal approvals, or compliance requirements, this kind of flow can really help. If you’re just sharing a few drafts internally, it might be overkill. The nice thing is that it builds on tools people already know: SharePoint, documents, dashboards. No big mental switch required, but with a fully customizable experience that can fit different industries and use cases.

Hackathon vibes

The hackathon was a blast. It’s always fun to build something new, especially when you can show it off, but when time pressure is present you get that extra push. Working with Robert was a blast as usual as well, pining ideas, brainstorming and using AI to help with code writing helped us get a lot done in a short time. We had a clear vision of what we wanted to build, but we also had to be flexible and adapt as we went along. It’s amazing how much you can accomplish when you focus and collaborate. We got some great feedback and ideas for how to make it even better. And of course, it’s always nice to see what other teams came up with. Looking at all the submissions is definitely worth a few minutes The creativity and innovation on display was really inspiring.

So if you ever want to play around with tech and build something cool, I highly recommend joining a hackathon. It’s a great way to learn, collaborate, and have fun. And who knows, maybe you’ll come up with the next big thing! 🚀!