HubSpot's old APIs stop being supported in 2027
If anything talks to your HubSpot through the API, it's probably using a version that loses support next year. Here's what's happening, how to check, and what order to do things in.
The short version
| When | What |
|---|---|
| March 2026 | HubSpot switched to date-based API versions, like /2026-09/, in place of v1 to v4 |
| March 2027 | v4 APIs become unsupported |
| September 2027 | v1, v2 and v3 APIs become unsupported, along with legacy public and private apps |
Unsupported doesn't mean they switch off on the day. It means HubSpot stops fixing bugs and security problems in them and makes no promise they'll stay stable. That's not something you want your lead flow running on.
What date-based versioning means
Instead of v1, v2, v3 and v4, every API now has a version named after the month it was released. New versions come out twice a year, in March and September, and each one is supported for 18 months. Breaking changes only happen at those two points, so it's more predictable than the old system once you're on it.
The catch is the move itself. For many v3 and v4 endpoints it's mostly a URL change. For others the request or response looks different, and some older v1 and v2 endpoints don't have a like-for-like replacement yet. HubSpot says full replacement notes for every legacy endpoint will come with the March 2027 release.
Who's affected
- Custom integrations and scripts your team or an agency built. These are the main risk.
- Data warehouse and BI connections that call the API directly.
- Marketplace apps, though that's the vendor's job to fix. Apps still on old APIs or the old app model after September 2027 lose their certification and can be delisted, so check the ones you rely on are moving.
Native HubSpot features and the standard integrations HubSpot runs itself aren't something you need to worry about.
How to check your portal
- Look at the developer home page. HubSpot shows a task card saying how many of your apps use APIs that are going unsupported, with a link to a migrations tab. It's based on calls actually being made, so it catches things nobody remembers building.
- Search the code. Anything with
/v1/,/v2/,/v3/or/v4/in a HubSpot URL needs moving. - Ask your vendors. One line to each app provider: "Are you on HubSpot's date-based APIs, and when?"
The order I'd do it in
- Now: list every integration, what it does and who owns it. Do your private apps at the same time, since they're usually the same list.
- By March 2027: move anything on v4 first, because its deadline is six months earlier.
- Spring to summer 2027: move the v1 to v3 calls, going straight to the date-based version. HubSpot specifically says not to hop to v4 on the way.
- Test in a sandbox before switching anything that creates or updates records.
Not sure what's connected to your portal? It's one of the things I check in the free health check, along with seven others. Twenty minutes, and you get a score out of 100. Book a free health check.