### [Read this on the main serverless docs site](https://www.serverless.com/framework/docs/providers/openwhisk/guide/web-actions)
# OpenWhisk - Web Actions
Functions can be turned into ["_web actions_"](http://bit.ly/2xSRbOQ) which return HTTP content without use of an API Gateway. This feature is enabled by setting an annotation (`web-export`) in the configuration file.
```
functions:
my_function:
handler: index.main
annotations:
web-export: true
```
Functions with this annotation can be invoked through a URL template with the following parameters.
```
https://{APIHOST}/api/v1/web/{USER_NAMESPACE}/{PACKAGE}/{ACTION_NAME}.{TYPE}
```
- _APIHOST_ - platform endpoint e.g. _openwhisk.ng.bluemix.net._
- _USER_NAMESPACE_ - this must be an explicit namespace and cannot use the default namespace (\_).
- _PACKAGE_ - action package or `default`.
- _ACTION_NAME_ - default form `${servicename}-${space}-${name}`.
- _TYPE_ - `.json`, `.html`, `.text` or `.http`.
Return values from the function are used to construct the HTTP response. The following parameters are supported.
1. `headers`: a JSON object where the keys are header-names and the values are string values for those headers (default is no headers).
2. `code`: a valid HTTP status code (default is 200 OK).
3. `body`: a string which is either plain text or a base64 encoded string (for binary data).
Here is an example of returning HTML content:
```javascript
function main(args) {
var msg = 'you didn't tell me who you are.';
if (args.name) {
msg = `hello ${args.name}!`;
}
return { body: `${msg}
` };
}
```
Here is an example of returning binary data:
```javascript
function main() {
let png =
return {
headers: { "Content-Type": "image/png" },
body: png };
}
```
Functions can access request parameters using the following environment variables.
1. `__ow_method` - HTTP method of the request.
2. `__ow_headers` - HTTP request headers.
3. `__ow_path` - Unmatched URL path of the request.
4. `__ow_body` - Body entity from request.
5. `__ow_query` - Query parameters from the request.
**Full details on this feature are available in this [here](https://github.com/apache/incubator-openwhisk/blob/master/docs/webactions.md).**