# Call Total.js API routes with API()
> Use API(url, name, data, callback) to call the actions of a ROUTE('API ...') endpoint, validation errors included.
Framework: jcomponent20
Product: jComponent 20 (jcomponent@20)
Language: en
Content-SHA256: 7d1c02bbcfea4e2f336b0f7c326061679b2258d315e46891c6b4e67046dc2b94
Snapshot: c0700e321579725c5cf4f5ace1ad7d2866d1b4f93c24a63c0b41b6b7998e976c
Sources: jcomponent20@3fedd009a277f50fddc608b97afbec553b67c51b
Review: not-recorded
`API(url, name, data, callback)` is the client side of the Total.js `ROUTE('API ...')` endpoints. It sends `POST url` with the body `{ schema: name, data: data }` and calls the callback with the response. When the server answers with an error (for example a validation error) the callback receives an array of errors: use the `ERROR(response, success, error)` helper to handle both cases in one place.
Put the address of the endpoint in `ENV()` once and reuse it.
```js definitions/math.js
NEWACTION('Math/add', {
name: 'Add two numbers',
input: '*a:Number, *b:Number',
action: function($, model) {
$.callback({ sum: model.a + model.b });
}
});
```
```js controllers/api.js
exports.install = function() {
ROUTE('API /api/ +math_add --> Math/add');
};
```
```html public/index.html
jComponent
```