# Authentication

{% content-ref url="authentication/access-tokens" %}
[access-tokens](https://docs.mastersindia.co/einvoicing/authentication/access-tokens)
{% endcontent-ref %}

{% content-ref url="authentication/api-key" %}
[api-key](https://docs.mastersindia.co/einvoicing/authentication/api-key)
{% endcontent-ref %}

## Authentication Header

### Access Token 

If you have chosen the access token approach then for authentication to work you will need to pass the token in request **headers** in the following manner

<table><thead><tr><th>Paramater</th><th width="232.33333333333331">Value</th><th>Description</th></tr></thead><tbody><tr><td>Authorization</td><td>JWT <strong>&#x3C;access_token></strong></td><td><strong>JWT</strong> remains constant following by a space and then the access token received from the associated API</td></tr></tbody></table>

### API Key

If you have chosen the API key approach then for authentication to work you will need to pass the token in request **headers** in the following manner

| Paramater | Value       | Description                                                |
| --------- | ----------- | ---------------------------------------------------------- |
| api\_key  | \<api\_key> | Pass the API key generated from the UI as is in the header |