HubSpot API versioning has been a major concern for developers working on the platform for years. The naming system for version 1, version 2, version 3, and version 4 was inconsistent across APIs, settings windows were short, and breaking changes arrived without a predictable rhythm. This will change from March 2026.
For context, an API, or application programming interface, is essentially the connection layer that allows external software to communicate with HubSpot, retrieve contact information, push updates, and trigger workflows. With versioning, HubSpot signals to developers that the API has changed.
Under the old system, these signals were inconsistent. Different parts of the API used different version numbers, deprecation notifications were brief, and breaking changes – updates that would cause an existing integration to stop working – could arrive as quickly as 90 days in advance.
For teams managing multiple integrations, this resulted in an ongoing maintenance effort with no predictable rhythm.
With this in mind, HubSpot has moved to date-based versioning of its public APIs, replacing the numeric schema with a /yyyy-mm/ format. The first release under the new system is /2026-03/, and the company has confirmed that the pattern will follow a fixed rhythm: new versions will ship in March and September each year.
Each version is immutable once released, meaning breaking changes only arrive in a new version and never mid-lifecycle. The minimum support window per version is 18 months. The change was announced as part of HubSpot’s Spring 2026 Spotlight Developer Changelog, released at the end of March.
What changes for developers
For anyone currently building on HubSpot APIs, the practical implications are obvious. Version /2026-03/ covers the latest API surfaces and is based on the latest v3 and v4 endpoints. If you already have the latest version of a particular API, migrating means updating the URL path, for example replacing /crm/v3/ with /crm/objects/2026-03/.
Older versions will continue to be supported in the following period. The CRM APIs announced at INBOUND 2025 /2025-09/ will remain supported until release /2027-03/. Current version 4 APIs will be supported until March 2027. The old APIs versions 1 to 3 continue to work. The schedule for support will be announced separately. However, HubSpot has already signaled that version 1 deprecations will move forward and version 1 of the Contact List API will expire on April 30, 2026.
HubSpot’s developer documentation clearly states the reasoning: “In the past, it was difficult to answer basic questions about which version to use, when things would change, and how to schedule updates. Date-based versioning aims to fix that.”
Why cadence is important
The twice-yearly release schedule – March and September, aligned with HubSpot’s broader platform release cadence – offers development teams something they’ve never had before with HubSpot integrations: a predictable planning horizon.
Previously, developers had to continuously monitor changelog updates and catch important changes with a minimum notice period of 90 days about deprecated versions. The 18-month support window per version is a significant extension of this offering. Teams managing multiple integrations can now align upgrades with their own release cycles instead of reacting to HubSpot’s internal schedules.
In parallel, the developer platform is switching to the same date-based naming convention. Platform Projects version 2026.03 became generally available on March 30, 2026 and matches the API version naming without introducing any functional dependencies between the two tracks.
The MCP server is now generally available
Buried in the same Spring Spotlight release is a separate update worth mentioning. HubSpot’s Remote MCP Server, which enables MCP-compliant clients to connect to HubSpot data and workflows, has completed beta and is now generally available to all HubSpot accounts.
The GA version adds writing features, engagement history, marketing content objects, and organizational context. For developers building AI agents or agent workflows based on HubSpot, this is important: MCP compatibility means agents can now interact with HubSpot CRM data over the same protocol standard that has become the standard mechanism for agent-to-tool connectivity across the AI ecosystem.
HubSpot noted in the changelog that AI agents and MCP-based integrations can now rely on a consistent, machine-friendly versioning model, providing the practical benefit of date-based versioning beyond human developers. An agent navigating versioned endpoints needs the same predictability as any developer.
Source: HubSpot Developer Changelog, Spotlight Spring 2026; HubSpot Developer Documentation, Date-Based API Versioning Guide; HubSpot 2026-03 API reference.
See also: AI discovers errors faster than teams can react
Want to learn more about cybersecurity from industry leaders? Checkout Cybersecurity and Cloud Exhibition takes place in Amsterdam, California and London. The comprehensive event is part of TechEx and takes place alongside other leading technology events including the AI and big data trade fair. Click Here for more information.
The developer is supported by TechForge Media. Discover more upcoming enterprise technology events and webinars Here.
