HubSpot is sunsetting Design Manager serverless functions and restricting Node.js 20 and earlier for workflow custom code actions, according to a developer changelog announced Nov. 3, 2026 and last updated Nov. 4.
The main dates
Date
Area
Change
Nov. 3, 2026
Design Manager serverless functions
New functions can no longer be created.
Nov. 3, 2026
Workflow custom code actions
New Node.js 20 custom code actions can no longer be created.
Nov. 17, 2026
Design Manager serverless functions
Existing functions can no longer be edited, including staging and deploying serverless packages through the Design Manager private beta. Existing functions keep running.
Nov. 17, 2026
Workflow custom code actions
Existing Node.js 20 actions can no longer be saved. Existing actions keep running.
Feb. 1, 2027
Design Manager serverless functions
Functions stop running, and requests to /_hcms/api/ endpoints fail.
The dates apply differently across the two product areas. For Design Manager serverless functions, Feb. 1 is the hard execution cutoff. For workflow custom code actions, HubSpot is not saying existing Node.js 16 or Node.js 20 actions stop running on Nov. 17. The immediate risk is that older actions become harder to maintain because saves are blocked until the runtime is moved forward.
Design Manager serverless functions are moving to developer projects
HubSpot says Design Manager serverless functions served from /_hcms/api/ run on Node.js 18 or 20, which HubSpot cannot upgrade. The supported replacement is a serverless function built in a developer project, served from /hs/serverless/.
The migration is not a direct runtime toggle. HubSpot says it cannot migrate these functions automatically because each function’s code and the pages that call it are unique to the site. Migrating means rebuilding the function in a developer project and updating the templates, modules, settings, or external callers that point to the old endpoint.
HubSpot’s migration guide says serverless functions require Content Hub Enterprise, so the Design Manager portion of the change mainly concerns accounts that have used that enterprise CMS feature. The same guide recommends that most affected teams migrate only the functions and leave templates or modules where they are, changing the endpoint prefix rather than moving an entire theme.
Older developer project versions also need attention
HubSpot says projects on 2023.1, 2023.2, or 2025.1 run functions on Node.js 18 or 20 and do not get Node.js security updates. Builds and deploys on those versions are already blocked. HubSpot says affected projects should be upgraded with hs project migrate and redeployed.
Projects already on 2026.03 or 2026.09 run Node.js 24 and do not need to be migrated for this change at this time. HubSpot lists 2026.09 as the current platform version for new projects.
Workflow custom code actions need code checks, not just a version switch
HubSpot says Node.js 24 is now available for workflow custom code actions. Existing Node.js 16 and Node.js 20 custom code actions keep running, but Node.js 16 actions already cannot be saved until they are switched to a newer version. Node.js 20 actions follow the same edit restriction on Nov. 17.
The runtime move can require code changes. HubSpot’s upgrade guide says Node.js 24 does not support callback-style handlers, so actions need to return outputs instead of calling callback(). The libraries available to custom code actions have also changed versions, which means testing each action before saving is part of the migration work.
HubSpot says Breeze can update custom code actions in a workflow, while the manual path involves finding affected workflows, updating code, checking library changes, testing, and rolling back if needed.
The security rationale tracks Node.js support status
HubSpot framed the change around runtime security updates. The Node.js project lists Node.js 18 and Node.js 20 as end-of-life releases, and its EOL guidance says release lines that reach end of life no longer receive updates, including security patches.
Older HubSpot custom functions may still run, but the unmaintained runtime base creates a growing security and maintenance problem for hosted custom code.
Developers raised concerns about the short notice
The HubSpot Community mirror of the announcement drew concerns from developers and partners about the amount of advance notice and the clarity of customer-facing communication.
In that same thread, HubSpot’s Jon McLaren clarified that existing Design Manager serverless functions remain active until Feb. 1, 2027. He also said the current blocks apply to creating new affected functions and new affected custom code actions, while migration can happen by creating new functions and switching callers rather than editing the old functions. McLaren said feedback about partner advance notice and partner-admin visibility would be raised internally.
What affected teams should check first
For businesses using HubSpot mostly through the standard CRM, marketing, sales, or service interface, the change may have no direct effect. The affected assets are custom code assets: CMS serverless endpoints, developer-project functions on older platform versions, and workflow custom code actions using older Node.js runtimes.
A practical first step is an inventory before changing code. The highest-priority checks are:
CMS templates, modules, page settings, blog settings, or external apps that call /_hcms/api/ endpoints.
Developer projects using platformVersion values 2023.1, 2023.2, or 2025.1.
Workflow custom code actions using Node.js 16 or Node.js 20.
Workflow actions that still use callback-style handlers or depend on older library behaviour.
Secrets, tokens, and HubSpot API scopes used by migrated functions.
Use that inventory to build a test plan and migration schedule before code freezes limit the available options.
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