Building a custom connector: bring your own API into Power Automate

A custom connector in Power Automate is a self-built wrapper around a REST or SOAP API that you use whenever none of the over 1,000 prebuilt connectors fits your system. You build it via an OpenAPI definition, a Postman collection, or directly in the connector portal, secure access via a standard authentication method such as Microsoft Entra ID or OAuth 2.0, and need at least a Power Automate Premium or Process license for it, since the Free tier only allows standard connectors. As of: August 2026.

What exactly is a custom connector?

A custom connector is technically a wrapper around a REST API, and for Logic Apps also around a SOAP API, that lets Power Automate, Power Apps, or Copilot Studio talk to a system for which no ready-made connector exists. The API can be publicly reachable on the internet, for example a self-hosted REST interface, or reside privately on your own network, for private APIs Microsoft provides an on-premises data gateway for this. Details on the overall concept are described in the Overview of custom connectors by Microsoft.

How do I actually build the connector?

You have three ways to define the connector: via an OpenAPI definition (formerly Swagger file), via an imported Postman collection, or by creating it completely from scratch in the connector wizard. According to Microsoft, the last way is only available in Power Automate and Power Apps, not in Logic Apps, whereas the OpenAPI or Postman definition can also be reused there to create the connector separately again. In solutions you create it via "New > Automation > Custom connector".

How do I secure the connection to the API?

Several standard methods are available for authentication, with Microsoft Entra ID recommended: generic OAuth 2.0, service-specific OAuth 2.0 for example for Dropbox or GitHub, basic authentication, or an API key. An important point for existing connectors: newly created OAuth 2.0 connectors automatically receive their own redirect URI per connector, older connectors had to be switched over to this since February 17, 2024, otherwise new connections no longer work. If you operate an older connector, it is worth checking the security settings to see whether the unique redirect URL is already enabled.

Which license do I need for this?

To be able to use a custom connector at all, you need at least a Power Automate Premium or a Process license, the free Power Automate Free license is, according to Microsoft, explicitly limited to standard connectors. The Premium, Process, and Hosted Process licenses each fully include the entitlement for custom connectors, there is no separate additional fee per individual connector. When deciding which license tier makes sense for your company, we at NordFlux support you as part of our Power Automate license consulting.

How do I share the connector within the team, and what applies to Logic Apps?

You share the connector within your organization, similar to other resources in Power Automate, Power Apps, or Copilot Studio, this is optional but useful as soon as several colleagues are meant to use it. A connector created in Power Automate is automatically also available in Power Apps and Copilot Studio, and vice versa, but this does not automatically apply to Logic Apps. If the connector is meant to become visible to all users of Power Automate, Power Apps, Logic Apps, and Copilot Studio, you must additionally submit it for Microsoft certification. According to the Overview of connector certification certification is free for both publisher types, but requires a supported authentication method (OAuth 2.0, anonymous authentication, API key, or basic authentication), a named support contact, and recommends an availability of at least 99.9 percent.

Frequently asked questions about custom connectors in Power Automate

Do I need programming skills for a custom connector?

For the simplest route via the connector wizard, basic knowledge of the target API's structure is enough, classic programming is not strictly necessary. However, as soon as you write an OpenAPI definition yourself or implement more complex authentication such as Microsoft Entra ID in your own API's code, technical know-how becomes significantly more helpful.

Does a custom connector cost extra on top of the license?

No, according to Microsoft, use of custom connectors is already included in the Premium, Process, and Hosted Process licenses, the documentation does not mention a separate fee per connector. Costs effectively arise from the fact that without these license tiers you cannot use a custom connector at all, since the Free license excludes them.

Can I also use a custom connector in Power Apps?

Yes, according to Microsoft a custom connector created in Power Automate is automatically also available in Power Apps and Copilot Studio. This does not apply directly to Logic Apps, but the same OpenAPI definition or Postman collection can be reused there.

What happens if the underlying API changes?

If a field in the API changes, you must republish the connector so that the updated Swagger is picked up, and then remove and re-add the affected connections in all apps. Without this step, apps and flows continue working with the old connector definition and can fail on differing fields.