What changed between GoHighLevel API v1 and v2?

The main change is authentication, with v2 using a more secure OAuth-based approach rather than the simpler API keys many v1 integrations use.

Do I need to migrate if I only use the GoHighLevel interface?

No. The migration affects custom integrations, raw HTTP calls in tools like Zapier or Make, internal dashboards and any custom-built apps.

What is the biggest risk in the migration?

Integrations that fail silently. A broken API call often stops delivering leads without producing a visible error, so verify that real data arrives after switching, not just that the code ran.

How should an agency approach the migration?

Inventory every place an API key exists, identify v1 calls, test in a sub-account first, then monitor real records after deployment.

GoHighLevel API v1 to v2: Agency Guide

HighLevel published guidance in June 2026 on migrating from API v1 to v2, centred on improved authentication. If your agency has built anything custom on the platform, this is not optional maintenance.

Who this affects

You are affected if any of these exist in your setup: a custom integration written by a developer, a Zapier or Make scenario using a raw HTTP call to the HighLevel API, an internal dashboard pulling data out, or a client-facing tool you built on top of the platform.

You are not affected if you only use the platform through its own interface and native integrations.

The main change

The headline difference is authentication. Version 2 uses a more secure OAuth-based approach rather than the simpler API keys many v1 integrations rely on. That is a genuine security improvement and it is also the thing that will break scripts written years ago and forgotten.

How to audit what you have

List every place an API key exists: automation tools, server scripts, spreadsheets, internal apps.
Check each one for calls to the v1 endpoints.
Note who wrote it and whether that person is still reachable. This is usually the real problem.
Test in a sub-account before changing anything in a client account.

The risk nobody plans for

The integration that breaks quietly. An API call that stops working does not always throw an error somebody sees. It often just stops delivering leads into the CRM, and you find out when a client asks why enquiries dropped.

So the migration checklist should end with monitoring rather than deployment: confirm that data is actually arriving after the switch, on a real record, not just that the code ran without error.

If you are a client rather than a developer

Ask whoever built your integrations one question: are we on API v2, and when was that confirmed? If the answer is vague, that is worth resolving before it becomes a silent outage.

Do it before you need to

Migrations forced by a deadline get done badly. Migrations done in a quiet week get tested properly. This is the second kind of work, and the cost of leaving it is a lead pipeline that fails without telling you.

Want this built for your business?

We build the funnel, the follow-up automation and the ad campaigns as one system. Fixed published pricing, 14-day build.

Book a free strategy call