Troubleshooting

This usually means that Mintlify cannot find your OpenAPI document or that the document is invalid.

Run mint dev locally to reveal some of these issues.

To verify your OpenAPI document passes validation:

1. Visit this validator.
2. Switch to the Validate text tab.
3. Paste in your OpenAPI document.
4. Click Validate it!

If the text box that appears below has a green border, your document has passed validation. Mintlify uses this exact validation package to validate OpenAPI documents. If your document passes validation here, the problem likely lies elsewhere.

Additionally, Mintlify does not support OpenAPI 2.0. If your document uses this version of the specification, you could encounter this issue. You can convert your document at editor.swagger.io (under Edit > Convert to OpenAPI 3).

A misspelled openapi field in the page metadata usually causes this issue. Make sure the HTTP method and path match the HTTP method and path in the OpenAPI document.

Here's an example of how things might go wrong:

---
openapi: "GET /user/{id}"
---

paths:
  "/users/{id}":
    get: ...

The path in the openapi field says /user/{id} (singular). The path in the OpenAPI document is /users/{id} (plural).

Another common issue is a misspelled filename. If you specify a particular OpenAPI document in the openapi field, ensure the filename is correct. For example, if you have two OpenAPI documents, openapi/v1.json and openapi/v2.json, your metadata might look like this:

---
openapi: "v1 GET /users/{id}"
---

This error means Mintlify could not download the OpenAPI document at the URL in your docs.json openapi field during the build. Common causes include:

• The host is unreachable or resolves only from a private network.
• The URL requires authentication (a token, session cookie, or IP allowlist).
• The certificate is invalid or the domain has a DNS issue.
• The origin returned a transient 5xx or timed out.
• The spec was being republished at the moment the build ran, so the URL served a partial or empty response.

Builds fetch the URL from the public internet without credentials, so confirm that the document downloads with curl from a machine outside your network. To fix the error, switch to one of these patterns:

• Commit the spec into your docs repo. This is the recommended pattern when the source URL is behind auth. Point the openapi field at the repo-relative path (for example, "openapi": "openapi.json") and update the file in the same commit that changes your API.
• Serve the spec from a stable public HTTPS URL. Host it on a CDN or object storage bucket that does not require auth, has a valid TLS certificate, and returns the full document on every request.

For a full diagnostic walkthrough, including intermittent failures caused by CI publishing the spec after triggering the build, see Build fails with "Failed to fetch OpenAPI file for anchor or tab".

If you use a custom domain, your reverse proxy might cause this issue. By default, the API Playground starts requests with a POST request to the /_mintlify/api/request path on the docs site. If your reverse proxy allows only GET requests, all of these requests fail. Configure your reverse proxy to allow POST requests to the /_mintlify/api/request path.

Alternatively, if your reverse proxy prevents you from accepting POST requests, configure Mintlify to send requests directly to your backend with the api.playground.proxy setting in the docs.json. See the settings documentation for details. When you use this configuration, requests come directly from users' browsers rather than through your proxy. Configure Cross-Origin Resource Sharing (CORS) on your server.

If you are using an OpenAPI navigation configuration, but the pages aren't generating, check these common issues:

1. Missing default OpenAPI spec: Ensure you have an openapi field set for the navigation element:

"navigation": {  "groups": [    {      "group": "API reference",      "openapi": "/path/to/openapi.json",      "pages": [        "GET /users",        "POST /users"      ]    }  ]}

2. OpenAPI spec inheritance: If using nested navigation, ensure child groups inherit the correct OpenAPI spec or specify their own.
3. Validation issues: Use mint validate to verify your OpenAPI document is valid.

1. Hidden operations: Operations marked with x-hidden: true in your OpenAPI spec won't appear in auto-generated navigation.
2. Invalid operations: Operations with validation errors in the OpenAPI spec may be skipped. Check your OpenAPI document for syntax errors.
3. Manual vs automatic inclusion: If you reference any endpoints from an OpenAPI spec, only the explicitly referenced operations appear in navigation. No other pages are automatically added. This includes operations that are referenced in child navigation elements.

Mintlify auto-generates a description for the Authorization field in the API playground based on the security scheme type. Add a description to the security scheme in your OpenAPI specification to override the generated text.

{  "components": {    "securitySchemes": {      "bearerAuth": {        "type": "http",        "scheme": "bearer",        "description": "Your API key from the [dashboard](https://example.com/dashboard). Send it as `Bearer <key>`."      }    }  }}

The description supports Markdown and replaces the auto-generated text on every endpoint that uses the security scheme.

When combining OpenAPI operations with regular documentation pages in navigation:

1. File conflicts: Mintlify does not support both an MDX file and a navigation entry for the same operation. For example, if you have get-users.mdx, do not also include "GET /users" in your navigation. If a file must share a name with an operation, use the x-mint extension for the endpoint so its href points to a different location.
2. Path resolution: Mintlify treats navigation entries that don't match OpenAPI operations as file paths. Ensure your MDX files exist at the expected locations.
3. Case sensitivity: OpenAPI operation matching is case-sensitive. Ensure HTTP methods are uppercase in navigation entries.