400 Error When Updating Contact Properties

[JaymeAlann]

We’re encountering a recurring 400 Bad Request error when attempting to update contact properties using the Mailjet API. The error consistently returns "Invalid key name" despite the fact that the property exists in our system. This issue appeared to resolve itself over the weekend—allowing us to successfully sync over 21,000 candidates—but as of this morning, the 400 error has resumed.

createdate is a static string property

Error Message

Failed to update properties: Unsuccessful: Status Code: "400" Message: "Invalid key name: "createdate""

Observed Behavior
The request fails with a 400 status and the message "Invalid key name: "createdate" even though:

• The property "createdate" exists in our account metadata.
• It works for most candidates, then randomly starts throwing errors.

Environment

• Mailjet API version: v3
• Language: TypeScript / Node.js
• Endpoint: https://api.mailjet.com/v3/REST/contactdata/{Contact_ID}

Code where error is occuring

const dataArray = Object.entries(properties)
      .filter(([, v]) => v != null && v !== "")
      .map(([Name, Value]) => ({ Name, Value }));

    try {
      await this.mailjet
        .put("contactdata", { version: "v3" })
        .id(contactId)
        .request({
          Data: dataArray,
        });
    } catch (err) {
      throw new Error(`Failed to update properties: ${err.message}`);
    }

[JaymeAlann]

Example Payload:

await mailjet
.put("contactdata", { version: "v3" })
.id(contactId)
.request({
Data: [
{ Name: "first_name", Value: "xxxxx" },
{ Name: "last_name", Value: "xxxxx" },
{ Name: "phone", Value: "xxxxx" },
{ Name: "tenstreet_status", Value: "Potential Lead" },
{ Name: "token", Value: "…JWT…" },
{ Name: "recruiter", Value: "xxxxx" },
{ Name: "worklist", Value: "xxxxxx" },
{ Name: "state", Value: "xxxxxx" },
{ Name: "appdate", Value: "2025-01-06T03:24:27Z" },
{ Name: "createdate", Value: "2025-01-09T10:31:12Z" }
]
});