---
"@context": https://schema.org
"@type": TechArticle
"@id": https://www.twilio.com/docs/api/errors/57018#article
headline: "57018: 'Event' value type must be Map"
url: https://www.twilio.com/docs/api/errors/57018
inLanguage: en
dateModified: 2026-03-25T13:47:45.000Z
author:
  "@type": Organization
  name: Twilio Developer Education Team
publisher:
  "@type": Organization
  name: Twilio
---

# 57018: 'Event' value type must be Map

Log Type: APPLICATION

Log Level: ERROR

## Description

Your request sent the `Event` field with the wrong type. Twilio expects `Event` to be a map, so this error appears when the request includes a non-object value. Messaging event payloads in Event Streams are published as JSON objects with nested `data` objects.

### Possible causes

* You sent `Event` as a string, array, number, or other non-map value.
* The request body does not match the JSON object structure used by Messaging event payloads.

### Possible solutions

* Send `Event` as a JSON object/map with key-value pairs, not as a scalar or array.
* Compare your payload with the published Event Streams examples and correct any field types before you retry the request.
* Use the debugging guide to inspect the request body and confirm the `Event` field is being serialized correctly.

#### Additional resources

* [Set Up A2P 10DLC Event Streams](/docs/messaging/compliance/a2p-10dlc/event-streams-setup)
* [Debugging Your Twilio Application](/docs/usage/troubleshooting/debugging-your-application)