# Authenticate

## This will create an API AccessToken for an Application

> Return  HTTP Status Code 200 (OK) with AccessToken
> \
> Returns HTTP Status Code 400 if could not authenticate

```json
{"openapi":"3.0.1","info":{"title":"The Payment API","version":"v1"},"paths":{"/api/ClientSession":{"post":{"tags":["Authenticate"],"summary":"This will create an API AccessToken for an Application","description":"Return  HTTP Status Code 200 (OK) with AccessToken\r\nReturns HTTP Status Code 400 if could not authenticate","requestBody":{"description":"","content":{"application/json-patch+json":{"schema":{"$ref":"#/components/schemas/ClientSessionRequest"}},"application/json":{"schema":{"$ref":"#/components/schemas/ClientSessionRequest"}},"text/json":{"schema":{"$ref":"#/components/schemas/ClientSessionRequest"}},"application/*+json":{"schema":{"$ref":"#/components/schemas/ClientSessionRequest"}}}},"responses":{"200":{"description":"Success","content":{"application/json":{"schema":{"$ref":"#/components/schemas/AuthenticationClientSessionResponse"}}}},"400":{"description":"Bad Request","content":{"application/json":{"schema":{"type":"array","items":{"$ref":"#/components/schemas/BrokenRule"}}}}}}}}},"components":{"schemas":{"ClientSessionRequest":{"required":["ClientId","ClientSecret"],"type":"object","properties":{"ClientId":{"type":"string","description":"Unique identifier for the API Partner; provided by FrontStream"},"ClientSecret":{"maxLength":500,"type":"string","description":"Key specifically paired to the clientId"}},"additionalProperties":false,"description":""},"AuthenticationClientSessionResponse":{"type":"object","properties":{"Token":{"type":"string","description":"This is the AccessToken you will use for any other API call","nullable":true},"ClientId":{"type":"string","description":"Unique identifier for the API Partner; provided by FrontStream","format":"uuid"},"ExpirationDate":{"type":"string","description":"The date and time at which the AccessToken will no longer be valid if not used first. Will always be 5 hours from when the response is sent.","format":"date-time"}},"additionalProperties":false,"description":""},"BrokenRule":{"type":"object","properties":{"ErrorCode":{"type":"integer","format":"int32"},"Message":{"type":"string","nullable":true},"LoggerMessage":{"type":"string","nullable":true}},"additionalProperties":false}}}}
```


---

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