topic Re: Clarification needed: Legacy app migration requirements for API-only integration in APIs & Integrations

Clarification needed: Legacy app migration requirements for API-only integration

DDeka — Mon, 02 Feb 2026 15:42:03 GMT

Hi,

I'm a developer maintaining a legacy public app that powers an integration listed on My employee's Marketplace (not HubSpot Marketplace).

Our app:

Uses HubSpot OAuth to obtain access tokens
Calls HubSpot APIs from external servers (Employee infrastructure)
Does not use CRM cards, serverless functions, UI extensions, or any hosted components inside HubSpot
Is not listed on the HubSpot App Marketplace

We received a warning: "New HubSpot Marketplace Install Flow Implementation Paused"

My questions:

Since we have no HubSpot Marketplace listing, does this warning apply to us?
Will our OAuth flow and API access continue to work without migration?
Is there a deprecation timeline for legacy apps that only use OAuth + API?

I need official confirmation to provide to my emplyee regarding what action, if any, is required.

Thank you in advance

Re: Clarification needed: Legacy app migration requirements for API-only integration

STierney — Mon, 02 Feb 2026 18:46:46 GMT

Hey @DDeka - thanks so much for posting in the Community!

All of this context is really helpful. I'd like to tag in some experts to see what insight they may have regarding your inquiries. @ChrisoKlepke, @ashleyidesign, and @Anton - any thoughts here?

Shane, Senior Community Moderator

Re: Clarification needed: Legacy app migration requirements for API-only integration

Anton — Mon, 02 Feb 2026 19:24:15 GMT

Hey @DDeka,
the question is why it's a public app if it's not listed in the HS Marketplace in first place.
If it's a company internal app, a private app (now Project app) might have done the job as well.

I'd say, that without a bit more details on how the app works and what it does (a brief overview should be enough) it's quite hard to say if this message affects you or not. I think it won't affect you.

In terms of timeline - here's a community topic of @evaldas and @SteveHTM discussing this topic.

Hope this helps

best,
Anton

Re: Clarification needed: Legacy app migration requirements for API-only integration

DDeka — Tue, 03 Feb 2026 08:42:27 GMT

Thanks @Anton for answering and for the reference. It was helpful!

About why it is not private - I am not 100% sure it should be.

Briefly, what the app does: it is embedded in our dashboard and allows users to generate an HS authorization token (HubSpot’s OAuth 2.0) to access some HS resources like files, sites, and blogs, and to share social media posts. All of this users can do via the HS API and without leaving our dashboard.

Considering the above, do you think I should migrate it to a project app?

thanks

Dominik