HighLevel API v1 Deprecation:
What It Means, What Could Break and How to Migrate

Two Sources, Two Levels of Urgency: What the Notice Says and What the Documentation Says

Two kinds of HighLevel source describe this change, and they don't carry the same weight. Keeping them apart matters because one of them is the reason you're reading this.

If you received the notice, plan to its date. The absence of that date from public pages is not evidence it will move. HighLevel has moved a deprecation date before: an older version of its webhook guide gave July 1, 2026 for a signature change, and current versions say September 1, 2026. Plan on the date you were given.

HighLevel API v1 Deprecation: Timeline, credential types, and migration sequence

Deprecation, End-of-Support and Shutdown Are Three Different Events

End-of-support is not a shutdown. For almost a year, "it still works" has been true and has meant that nobody is maintaining it. An integration that works today is not evidence that it will work after the shutdown date, and the second row of that table is already running on its own clock.

What "API v1" Means in Plain English

Sometimes the action you want can't happen entirely inside HighLevel. Another system needs to push information in, or pull it out. An API is the doorway for that conversation. API v1 is the older doorway. It is opened with a legacy API key, which HighLevel describes as unrestricted access to your account's data. The newer doorway works with tokens that carry only the permissions you choose.

That one fact explains most of the urgency. A legacy key is a master key. Anything holding it, whether a tool, a contractor's script or an old laptop, can act on the whole account, which is why HighLevel is retiring the model.

The Terms HighLevel Uses, Kept Apart

Private Integration Token in Four Lines

• What it is: a credential an integration uses to authenticate with HighLevel, created in settings with only the permissions (scopes) you choose.
• Why it exists: to replace the broad access of a legacy key with least-privilege access.
• How it affects you: a migrated integration needs a new credential, and often a different set of permissions, rather than a copy of the old one.
• When it matters: for internal tools and automations that connect one business's account. HighLevel's guidance is that PITs are for internal use and OAuth 2.0 is for apps other accounts install.

Who Is Actually Affected: Not Every HighLevel User

The shutdown matters if something in your environment still calls the legacy API. Plenty of HighLevel accounts run entirely on native workflows, forms and integrations that already use the current API and never touch a legacy key. If you received the notice, something does. The task is to find out what.

Seeing Zapier, Make or n8n in your stack proves nothing by itself. The question is which connection each one uses.

The Hard Part Is Finding What Still Depends on the Old API

Legacy integrations survive for years because they work. Nobody writes documentation for something that has never failed. The original developer moves on. The credential lives inside another tool, so the business owner sees only the outcome: a contact appears, a number updates, a notification arrives. The mechanism is invisible until it stops.

A business can have hundreds of workflows inside HighLevel and still depend on a single undocumented script outside it for lead capture. That is why this reads as a developer notice and behaves like a continuity problem. Think of every connection as one of three flows, and ask where a credential sits in each.

How to Find Out Whether Your HighLevel Setup Still Uses API v1

Work through these in order. Each answers a different question, and none requires writing code.

1. Read the notice for specifics. Note which account or sub-account it names and anything it lists. Don't assume it names the tool.
2. Look for legacy API keys in settings, at both agency and sub-account level. A key marked Expired hasn't been used for 90 days, which tells you it is either dormant or seasonal. Keys still shown as active are being used, or were refreshed recently.
3. List every tool that talks to HighLevel: Zapier, Make, n8n, custom applications, forms, scripts, CRM integrations, middleware and agency-built systems.
4. Check the connection type inside each tool, using the table above. A connection described as API key, legacy or deprecated is a candidate.
5. Find out who built each one, where its documentation is, and whether that person is still reachable.
6. Don't use revocation as a test. Revoking or deleting a key to see what complains is a production experiment. HighLevel's own guide says to leave the old setup running until the replacement works.

The help pages reviewed here don't describe a report showing which tool made which v1 call, so discovery usually comes from the tool side and from logs. Keep a simple inventory as you go.

What Could Stop Working, and What Probably Won't

Your whole HighLevel account is not going offline. Specific integrations that depend on unavailable v1 endpoints may fail, and how badly depends entirely on what each one does.

The dangerous failures are the quiet ones. A loud error gets fixed. A lead form that stops creating contacts looks, from the outside, like a slow week.

Is This Just Replacing the API Key? Usually Not

HighLevel's migration guide tells you not to assume this is only an authentication change, because requests and responses can differ between the legacy and current APIs. Its June 26 post says most migration problems come from scope mapping, authentication handling and webhook configuration, not from changing a URL.

The v1 host and the header details come from integration-platform documentation rather than HighLevel's current pages, so confirm them against your own code. The pattern holds regardless: a credential swap alone rarely finishes the job.

What Replaces API v1: Private Integration Token, OAuth 2.0 or Something Else

There isn't one replacement. HighLevel's own guidance splits it by what the integration is, and a wrong choice here is costly to undo.

Private Integrations are created at agency and sub-account level. By default agency admins can create them, and the permission can be restricted by role. If you can't find the setting, HighLevel says to check that the feature is enabled under Labs. HighLevel's API documentation also still describes differences in API access by plan, so confirm what yours supports before committing to a design.

A Safe Migration Sequence

Notice received → Find the dependency → Choose the path → Rebuild alongside → Test → Cut over → Retire the old

The sequence in one line. The highlighted step is where HighLevel's guidance is most specific: don't edit the live automation.

1. Inventory every legacy dependency: the keys, the tools using them, what each one does and who owns it.
2. Document what each integration really does before building anything: trigger, source, action, endpoint, fields, destination, permissions, expected response and downstream effect.
3. Decide the architecture using the table above. Don't force a PIT onto everything.
4. Create replacement credentials with only the scopes that integration needs. Copy the token somewhere secure immediately, because HighLevel shows it once.
5. Build the new implementation alongside the old one. HighLevel's guide says not to edit existing, active automations. Keep them running, create new ones, and duplicate rather than modify.
6. Test properly (next section), with a test lead first.
7. Cut over deliberately. Turn on the new automation, pause the old one, watch the first real records, and only then delete the old automation and key. Running both live against the same trigger can process one lead twice.
8. Monitor and document. Write down what exists now, which token belongs to what, and when each is due for rotation.

Testing the Replacement: Why a Successful Login Proves Almost Nothing

A successful authentication test proves a credential is valid. It doesn't prove the business process works, which is the thing you're actually trying to protect.

One successful record is a demonstration, not a test. Run at least a second, different, realistic record before trusting it.

When a Migrated Integration Misbehaves

Ten Migration Mistakes That Cause Outages

1. Deleting the old key before the replacement works.
2. Editing the live automation without a copy. Duplicate it, then change the duplicate.
3. Assuming it's a credential swap. Requests, responses and scopes may differ.
4. Granting the new token too much. Copying broad v1 access into a PIT defeats the purpose.
5. Testing only that authentication succeeds.
6. Testing one record and calling it done.
7. Ignoring downstream systems. A contact created correctly can still fail to trigger what comes next.
8. Migrating one integration and missing another. An inventory is the defence.
9. Not documenting the result. The next person will face the same mystery you did.
10. Discovering late that the developer is gone. Find out now who built each integration.

A Separate Deprecation in the Same Project: Webhook Signatures

Webhooks are HighLevel sending event data to a URL you control, which is a different mechanism from API calls into HighLevel. HighLevel's webhook guide says the legacy X-WH-Signature header (RSA) is deprecated on September 1, 2026, after which webhooks are signed only with X-GHL-Signature (Ed25519). An earlier version of the guide gave July 1, 2026 for the same change.

This isn't part of the API v1 shutdown. It matters because a project that moves every API call to a Private Integration can still leave a webhook receiver verifying only the old header. Many simple receivers don't verify signatures at all, in which case there is nothing to change. If yours does, check it now, since the date in the current guide has passed.

Can You Migrate This Yourself, or Does It Need a Specialist?

The more undocumented, interconnected and business-critical a system is, the more a proper audit is worth. Complexity, not importance, is what separates the two columns below.

Where you can get help matters. HighLevel's API documentation says its Support team doesn't provide setup code auditing or developer consulting, though bugs can be reported and a developer community exists. A single, well-defined integration is often a freelancer job. Anything spanning several systems benefits from architecture planning and testing, which is the freelancer-versus-agency distinction explained in where to hire GoHighLevel experts, along with vetting questions and the account-access questions to settle before anyone touches your account.

What to Gather Before You Ask Anyone for Help

• The HighLevel notice email, in full.
• The affected account and sub-accounts.
• Each integration's name, what it does and the external tool involved.
• Which credential each one uses, described without exposing the secret.
• Screenshots of settings, scenarios and Zaps with secrets hidden.
• How it behaves today and what correct behaviour looks like.
• Known errors, and when they started.
• Any developer documentation or code repository.
• Webhook URLs and what receives them.
• Which workflows are business-critical.
• Who originally built each integration, and whether they're reachable.

Never paste a live API key, token or secret into a public support thread, an article comment, a screenshot or an AI prompt. HighLevel says to share a Private Integration Token only with trusted parties and notes it can't be shown again. Granting a developer access to create their own scoped integration is often safer than handing over an existing credential.

Why Waiting Makes This Harder

Nothing about this requires panic. It requires time, and the time shrinks in predictable ways as the date HighLevel gave you approaches:

• There is less time to find unknown dependencies, and discovery is the slowest part.
• Tracking down the original developer takes longer than anyone expects.
• There is less room to test with realistic volume and edge cases.
• A planned migration turns into an emergency one, done under failure rather than beside a working system.
• Scheduling production changes gets harder when several integrations all need attention in the same weeks.
• Keys inactive for 90 days may already be marked Expired, so some failures can arrive earlier than any shutdown date.

How an Integration Audit Works, and Where GHL Scale Up Fits

If your setup is complicated, the useful first step isn't a rebuild. It's an audit that answers four questions: what is calling HighLevel, what does each call do, what replaces it, and what happens to the business if it stops.

GHL Scale Up's integrations and API development service covers custom API connections, webhooks and Zapier or Make integrations, and describes a process that runs from discovery and architecture mapping through connection and authentication, workflow configuration, and testing with real data and monitoring. For an API v1 warning, that translates into an audit-first sequence:

Audit → Identify → Plan → Rebuild → Test → Cut over → Validate

• Audit and identify: list every legacy credential and the tools, scripts and forms using each one.
• Plan: establish what each integration does, what replaces it, and whether the credential type is a PIT, OAuth or something else.
• Rebuild and test: build alongside the old integration and test the layers in the table above.
• Cut over and validate: switch deliberately, watch real records, then retire the old credentials.

Whether a given setup turns out to be a quick connection change or a rebuild is what an audit establishes. No outcome is promised in advance.

Not sure what in your HighLevel account is still using API v1? The integrations service page above describes how to request an integration audit. Bring the checklist from the previous section.

The Question to Answer This Week

The deadline matters less than what it forces. Every business that received this notice is being asked a question it should have been able to answer already: what is connected to our CRM, who built it, and what breaks if it stops. The migration is the smaller task. The inventory is the one most people skip.

Start there. Even if you end up changing a single credential in ten minutes, you'll know your lead capture, your sync and your reporting no longer depend on something nobody can name.

Frequently Asked Questions About the HighLevel API v1 Deprecation

GHL Scale Up Team

GoHighLevel expert agency · 5+ years GHL experience · 200+ systems built and migrated globally

GHL Scale Up is a specialised GoHighLevel implementation and SaaS growth agency. Based in India, we serve agencies and businesses across 6 countries with 200+ GoHighLevel builds delivered. This guide reflects direct experience auditing and migrating HighLevel API v1 integrations. All product details verified against HighLevel documentation as of October 2026.

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