Status Codes

CategoryHTTP Status CodeCodeExplanation

2xx Success


Everything worked as expected with content returned.


1. Everything worked and MX’s system is processing the request. 2. When attempting an aggregation on a member, an aggregation of the same type is already running; e.g., calling aggregate member while a previous aggregation is still running, or calling verify member while a previous verification is still running.

No Content

Everything worked as expected without content returned.

4xx Requester error

Bad Request

Often, this means a required parameter was missing.


Invalid MX-API-Key or MX-Client-ID provided.


The request was made from a non-whitelisted address or the feature is not available to the client.

Not Found

Invalid item/id/URL requested.

Method Not Allowed

A constraint on the requested endpoint wasn’t met.

Not Acceptable

The request didn’t specify a valid API version.


1. An object with the given attributes already exists. 2. When attempting an aggregation on a member, the member already has an an aggregation of a different type running; e.g., calling the verify endpoint while a standard aggregation is already running, or calling fetch statements while an identification aggregation is already running.

Unprocessable Identity

The data provided cannot be processed.

5xx Responder error — which are rare

Server errors

Something went wrong with MX’s servers.

Service unavailable

The MX Platform is being updated.