---
id: invoke
title: 'invoke()'
slug: /invoke
custom_edit_url: https://github.com/supabase/supabase/edit/master/spec/supabase_js_v2_legacy.yml
---
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Invokes a Supabase Function.
```js
const { data: user, error } = await supabase.functions.invoke('hello', {
body: { foo: 'bar' },
})
```
## Parameters
## Notes
- Requires an Authorization header.
- Invoke params generally match the [Fetch API](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API) spec.
- When you pass in a body to your function, we automatically attach the Content-Type header for `Blob`, `ArrayBuffer`, `File`, `FormData` and `String`. If it doesn't match any of these types we assume the payload is `json`, serialise it and attach the `Content-Type` header as `application/json`. You can override this behaviour by passing in a `Content-Type` header of your own.
- Responses are automatically parsed as `json`, `blob` and `form-data` depending on the `Content-Type` header sent by your function. Responses are parsed as `text` by default.
## Examples
### Basic invocation.
null
```js
const { data: user, error } = await supabase.functions.invoke('hello', {
body: { foo: 'bar' },
})
```
### Error handling.
A `FunctionsHttpError` error is returned if your function throws an error, `FunctionsRelayError` if the Supabase Relay has an error processing your function and `FunctionsFetchError` if there is a network error in calling your function.
```js
import {
FunctionsHttpError,
FunctionsRelayError,
FunctionsFetchError,
} from '@supabase/supabase-js'
const { data: user, error } = await supabase.functions.invoke('hello', {
headers: {
'my-custom-header': 'my-custom-header-value',
},
body: { foo: 'bar' },
})
if (error instanceof FunctionsHttpError) {
console.log('Function returned an error', error.message)
} else if (error instanceof FunctionsRelayError) {
console.log('Relay error:', error.message)
} else if (error instanceof FunctionsFetchError) {
console.log('Fetch error:', error.message)
}
```
### Passing custom headers.
You can pass custom headers to your function. Note: supabase-js automatically passes the `Authorization` header with the signed in user's JWT.
```js
const { data: user, error } = await supabase.functions.invoke('hello', {
headers: {
'my-custom-header': 'my-custom-header-value',
},
body: { foo: 'bar' },
})
```