Upload a well-known file

Add .well-known configuration files to your Webflow site to support deep linking, security protocols, and third-party service verification.

The .well-known directory is a standardized location defined by the Internet Engineering Task Force (IETF) where web servers store metadata files that other systems can easily locate. Adding these files to your Webflow site lets you expose configuration, authentication, or service-related information for various protocols and use cases.

Well-known files can define rules for:

Deep linking between your website and mobile apps
Security protocols and verification
Domain validation
Third-party service integration

Upload well-known files

To add well-known files to your site:

Go to the Assets panel
Create a new folder named "well-known"
Upload your configuration files to this folder
Publish your site

When you publish, Webflow automatically moves all files from the well-known folder to your site's /.well-known/ directory.

To replace existing well-known files:

Go to the Assets panel
Upload the new configuration file to the well-known folder using the same filename as the existing file
Publish your site

Supported file types and restrictions

Well-known files must be .json or .txt files. If you need to upload a file without an extension, rename it with a ".noext" extension (For example, my-file.noext.txt) and Webflow will remove the extension before serving it.

The following restrictions apply:

Maximum file size: 100KB
Maximum number of files: 30
Available on Premium Site plans (and legacy Business Site plans) or higher
Not available on webflow.io staging domains
Cache invalidation occurs on publish to ensure changes are reflected immediately

Good to know

Existing .well-known files (apple-app-site-association and apple-developer-merchantid-domain-association) on other Site plans will continue to work, but adding new files requires a Premium Site plan (or legacy Business Site plan) or higher.

Valid and invalid file examples

	Examples
Valid file	Supported file type with a valid extension Extension: .json or .txt Name: my-file.json, my-file.txt, my-file.noext.json
Invalid file	File kind = "document" Extension: .noext or without extension Name: my-file or my-file.noext

Behavior for the .noext extension

	Behavior
With .noext	The extension is removed from the filename in the directory structure. my-file.noext.json > https://website.com/.well-known/my-file my-file.noext.txt > https://website.com/.well-known/my-file my-file.noext > https://website.com/.well-known/my-file This is valid only if you renamed my-file.txt to my-file.noext, so the file Kind = "Plain text Document." On Windows, renaming without the secondary extension may not work as expected — use my-file.noext.txt to be safe.
Without .noext	Files retain their extensions in the directory structure. my-file.json > https://website.com/.well-known/my-file.json my-file.txt > https://website.com/.well-known/my-file.txt my-file > https://website.com/.well-known/my-file

Behavior

With .noext

The extension is removed from the filename in the directory structure.

my-file.noext.json > https://website.com/.well-known/my-file
my-file.noext.txt > https://website.com/.well-known/my-file
my-file.noext > https://website.com/.well-known/my-file

This is valid only if you renamed my-file.txt to my-file.noext, so the file Kind = "Plain text Document." On Windows, renaming without the secondary extension may not work as expected — use my-file.noext.txt to be safe.

Without .noext

Files retain their extensions in the directory structure.

my-file.json > https://website.com/.well-known/my-file.json
my-file.txt > https://website.com/.well-known/my-file.txt
my-file > https://website.com/.well-known/my-file

Important

"File kind" and "Kind" reflect how macOS interprets the file based on metadata, Uniform Type Identifiers (UTIs), or file headers. This is more reliable than extension-based identification since it works even if the extension is missing or misleading. On other operating systems, make sure the file extension is set correctly.

Security and verification

You can use well-known files to implement security protocols and verify domain ownership. Common use cases include:

security.txt — provides security policy information
Matrix server delegation — delegates Matrix server routing
Domain verification — verifies ownership for services like Discord and Apple

Common use cases

One common use case is configuring deep linking between your website and iOS app using the apple-app-site-association file. To set this up:

Create your apple-app-site-association file in JSON format
Upload it to your well-known folder in the Assets panel
Publish your site

After publishing, the file will be available at: https://yoursite.com/.well-known/apple-app-site-association

Note

If you previously uploaded an apple-app-site-association file outside the well-known directory, uploading a new file to the well-known folder will replace the existing configuration. The old file will remain in the Assets panel for reference.

Best practices

Keep your configuration files as small as possible
Use the exact filenames required by the service or protocol you're supporting — naming matters
Review your service provider's documentation for specific file requirements
Test your configuration files after publishing to confirm they're accessible

Duplicate file content

Webflow checks file content when determining duplicates during asset uploads. If two files have the same content, they're treated as identical even if their names or extensions differ. For example, if you upload myfile.txt and then upload a renamed copy called myfile.json with the same content, the original file will be replaced rather than stored separately.

To store files separately, modify the content of one file before uploading. This behavior is by design and helps avoid duplicate content in storage.