How to Build a Reliable GoHighLevel API Integration

A GoHighLevel API integration connects B2B applications directly to this CRM platform. This connection allows developers to sync contacts, trigger workflows, and read account data automatically. Teams can build this architecture from scratch to handle authentication, rate limits, and event structures directly. Alternatively, developers can skip the infrastructure work by adopting a unified CRM API that supports GoHighLevel. Both approaches require understanding how the target platform manages data access and resource constraints.

This guide covers the API version to build against, the two authentication methods, rate limits, the core lead and contact endpoints, webhooks, and the gaps in the official documentation.

Key Takeaways

• GoHighLevel’s API uses Private Integration Tokens or OAuth 2.0 for access.
• Webhooks send real-time system updates to avoid continuous polling.
• The platform creates leads as standard contacts via the POST /contacts endpoint.
• Check GoHighLevel’s current developer documentation for the rate limits that apply to your app.

Which GoHighLevel API Version to Use

• v3 is the current version. HighLevel released it on June 11, 2026. The Contacts API is served under a /v3 route prefix and returns AIP-compliant responses.
• Dated versions are still listed. The docs also list the 2023-02-21, 2021-07-28 and 2021-04-15 versions and a legacy version. None of them has an end-of-support date yet. The docs say that once a newer version is released, the previous one enters a maintenance window, where it gets critical bug fixes and security patches but no new features. The 2021-07-28 reference still lists contact and opportunity endpoints, such as Get Contact, Create Contact, and Create Opportunity, and some examples still send Version: 2021-07-28.

Send the version in the Version request header. For a dated version, pass the exact date string. Named versions such as v3 are passed the same way.

If you’re starting a new integration, build against v3. Check the v3 reference for the exact path and header of each call before you copy an example from an older page.

Authentication: Private Integration Tokens vs. OAuth 2.0

GoHighLevel’s API supports two distinct authentication methods. Developers choose between a Private Integration Token and OAuth 2.0 during the initial application setup.

The Private Integration Token operates as a static Bearer token. An agency admin creates this token under agency settings, in Private Integrations (if you do not see it, enable the feature under Labs). Select only the scopes the app needs, then copy the token right away, because it is shown only once. Share it only with people you trust. HighLevel recommends rotating it every 90 days; after a rotation, the old token keeps working for 7 days. This method works best for internal tools or single-account scripts.

OAuth 2.0 provides a standard authorization flow. HighLevel’s documentation describes OAuth 2.0 for Marketplace apps that other accounts install, or when one app needs several locations or accounts. Its access tokens expire daily. The platform does not refresh them for you: when a request fails because the access token has expired, refresh the token using the API, save the new access token and refresh token, and then retry the request. Both authentication methods ultimately rely on a standard Bearer Token for API requests, sent in the Authorization header as Bearer <token>. Because documentation changes frequently, check the provider’s official resources to confirm current endpoints and required token scopes before deploying production code.

With Knit: Knit handles client OAuth credentials setup using the POST /integration.registerOauthCreds endpoint.

Which ID goes where

• Location ID (also called Sub-Account ID) identifies a single sub-account. You find it under Settings, then Business Profile, in the sub-account.
• Company ID (Agency ID) identifies the agency. You find it under Settings, then Company, in the agency view.

A Private Integration Token needs the Location ID.

Managing GoHighLevel API Rate Limits and Pagination

Pulling large datasets requires careful rate limit management to prevent dropped requests. By default, each Marketplace app gets 100 requests per 10 seconds (burst) and 200,000 requests per 24 hours, counted per app per location or company. Each install gets its own budget, so installing the app on more sub-accounts doesn’t split the allowance. Private Integration tokens share one daily counter per location or company. Responses include X-RateLimit-Max, X-RateLimit-Remaining, X-RateLimit-Limit-Daily, X-RateLimit-Daily-Remaining, X-RateLimit-Daily-Reset and X-RateLimit-Interval-Milliseconds, so read them to track your usage. On a 429, wait the reset window before retrying. The 429 response has no Retry-After header, so use these headers to decide when to retry.

The official developer documentation omits universal pagination defaults across all endpoints. Developers must check the specific resource documentation to determine if it requires cursor-based or offset-based navigation logic. Building systems to manage these technical constraints forms the basis of how API integrations connect software systems.

Core Endpoints: Creating Leads and Contacts

Syncing contacts represents the most common use case for a B2B CRM integration. HighLevel does not offer a separate endpoint for sales leads. The system stores and creates all leads as standard contact records.

Developers issue requests to the POST {BASE_URL}contacts/ endpoint to create a new contact. Depending on user interface defaults, this record may appear as a lead or a contact inside the application. The JSON request body accepts multiple fields to populate the profile. Supported fields include locationId, firstName, lastName, email, phone, companyName, website, source, address1, city, state, country, postalCode, assignedTo, tags, and customFields. Formatting these payload structures accurately prevents sync failures, much like mapping distinct user fields when pulling calls and transcripts from Gong.

Using GoHighLevel Webhooks for Real-Time Syncing

Polling the go high level API continuously consumes your available rate limits quickly. HighLevel’s webhook guide sets up webhooks on a Marketplace app: in the app’s advanced settings, turn on the webhook section and paste your endpoint URL against each event you want, such as ContactCreate or ContactUpdate. The guide did not describe an equivalent for Private Integration tokens.

The Inbound Webhook workflow trigger gives each trigger its own unique HighLevel URL and accepts POST, GET and PUT requests. This is a workflow trigger, not the API event webhooks configured on a Marketplace app.

With Knit: Using the POST /events.subscribe endpoint, Knit allows developers to subscribe to real-time events across integrations.

Handling Gaps in the GoHighLevel API Documentation

Technical documentation often lacks coverage of edge cases and specific error structures. HighLevel documents the rate-limit headers and the 429 response. The pages checked for this post do not cover pagination, so confirm it on each resource’s page. Avoid guessing endpoint behavior when building production syncs.

Handle HTTP 429 and 500 status codes globally to maintain application stability. Just as developers verify required payload properties when retrieving detailed customer information from Affinity, testing undocumented GoHighLevel endpoints manually prevents sudden failures.

With Knit: Developers check integration configurations using the GET /integration.details endpoint to retrieve app status and logos by passing the originOrgId parameter. Knit also allows cleanly disabling an integration via the POST /integration.deactivate endpoint.

Before You Go Live

1. Create a Private Integration in a test sub-account and make one read call (for example, Get Contact) to confirm the token and scopes work.
2. Check the X-RateLimit-Daily-Remaining header during testing to see your remaining daily headroom.
3. Build OAuth token refresh into the client from the start. Expired tokens are normal, not an error.

Frequently Asked Questions

Developers often face similar questions when setting up authentication and testing endpoints. Below are direct answers regarding token generation and API versioning.

How do I get a GoHighLevel API token?

When you install the app, HighLevel’s OAuth 2.0 token exchange takes a user_type value. Company returns an agency-level token that can reach all sub-accounts; Location returns a token for one sub-account. Access tokens last 86,399 seconds, and refresh tokens last one year or until used.

Which GoHighLevel API version should I use?

Use v3, the current version, which HighLevel released on June 11, 2026. Dated versions are still available. The version section above explains how to send the Version header.