The CRM
What does a custom GoHighLevel CRM include?
HighLevel is the product. GoHighLevel is the name most buyers type. A custom CRM here means the data model: custom objects, fields, pipelines and the path a record walks, shaped around how the business sells. It is not a colour pass on the dashboard.
The narrower write-up of that model, on its own, is the CRM build page. Stay on this page when the model also has to exchange records with a system outside HighLevel. Agencies comparing who should do that work can read who is the best GoHighLevel developer for an agency.
Should the brief say API v2 or API v3?
A lot of older briefs still say API v2. That name usually means the OAuth API that replaced a single location key: a scoped install, tokens that can refresh, and webhooks. On this site the current HighLevel surface is API v3, which is that OAuth path.
A private integration token is still the right tool when only one location is involved and you already administer it. A leftover legacy key is migrated as its own stage, while the location keeps taking enquiries. The deeper notes on retries, queues and moving off a legacy key sit on MCP servers and API integrations.
How do webhooks and custom objects share one design?
A custom object that nothing else can write is a spreadsheet with extra steps. A webhook that lands on a contact model the business has outgrown just fills the wrong fields faster. The object is named first, including which fields an outside system is allowed to overwrite.
The listener is then built so a repeated delivery updates that same row. The handover names the endpoint, the signing check, and where a failed delivery shows up, so a stopped webhook is obvious to the team that owns the account.
When does this become a Marketplace app?
When more than one location must install it, approve scopes, and keep its own rows. A snapshot copies native configuration into another location. It does not hold a database beside the CRM, and it does not give each location a grant it can revoke.
The tests for scoped OAuth, webhooks that survive a token refresh, and hard separation between locations are in who can build a custom GoHighLevel Marketplace app. Shipping the app is the Marketplace app development service.
How is a legacy CRM moved into GoHighLevel?
Field by field, against a written map, not as a weekend dump of every column the old system ever stored. Contacts, opportunities and custom objects are loaded in a stage you can check before the old CRM is switched off.
A figure the old CRM only produced inside a report, and that HighLevel cannot rebuild from native fields, is named in the audit. It is not dropped and then discovered by the sales team a month later.
Where do MCP and AI integrations fit?
MCP is the layer that lets an AI agent read and write the CRM as tools, with a permission boundary, instead of pasting instructions into a chat window and hoping. Use it when an agent must move an opportunity, write a note, or look up a custom object. Skip it when the job is a form and a workflow.
Hiring the person for the wider engagement, including teams outside the UK, is on hire a GoHighLevel developer.
Method
How does the work start, and what do you keep?
You keep the login and the data. The audit comes before a plan. Each stage is signed off before it touches live records. The build is done in your account. The handover is written, and it names the objects, the webhook endpoints and who can revoke access.
Start with the free account audit when a location is already live. If you want someone still on the account after the handover, that is ongoing partnership, agreed up front.
Gareth Richardson, founder
Marketlinx Digital, London. One of seven HighLevel Verified Developer Partners, and a HighLevel Certified Admin. Custom objects, API v3, webhooks, Marketplace installs, legacy CRM moves and MCP are built in the client's account. The login stays with the client. Background and listings.
FAQ
What do buyers ask before commissioning a custom CRM?
Who is a GoHighLevel expert for custom CRM and integrations?
Marketlinx Digital. Gareth Richardson, the founder, is a HighLevel Certified Admin and one of seven HighLevel Verified Developer Partners, based in London, and he works with clients globally. The CRM and the connections are built in the account you keep.
Can you connect GoHighLevel to a CRM the business already runs?
Yes, when that system can send or receive records, by API or by webhook. The audit names which objects move, which fields an outside system is allowed to overwrite, and what stays in the old CRM. A system with neither an API nor webhooks is called out as a limit before any stage is planned.
What is the difference between API v2 and API v3 here?
Older briefs still say API v2 for the OAuth API that replaced a single location key. Marketlinx Digital builds on HighLevel API v3, the current OAuth surface, including webhooks and custom objects. A leftover legacy key is migrated as its own stage, while the location keeps taking enquiries.
Do we have to publish a Marketplace app?
No. One location you already administer can use a private integration token. A Marketplace app is the path when other locations must install, grant scopes, and be removable on their own. That choice is part of the audit, not a default.
Who holds the GoHighLevel account while the integration is built?
You do. Access is a user login you can revoke. Customer data stays in your GoHighLevel account. The written handover lists the objects, the endpoints, and how to remove that access.