API Documentation Issue - startTimestamp Parameter Format for Marketing Email Statistics Endpoint

Developer Support APIs & Integrations
1

Dear HubSpot Support Team,

I’m encountering an issue with the Marketing Email Statistics API endpoint and need clarification on the proper parameter format.

**API Endpoint:** GET /marketing/v3/emails/statistics/list
**Issue:** Unable to parse value for query parameter: startTimestamp
**Error Response:**
{
“correlationId”: “ff2b0f1e-288e-4384-abc0-78b98ac94ff2”,
“message”: “Unable to parse value for query parameter: startTimestamp”,
“status”: “error”
}

**Request Details:**
- URL: https://api.hubapi.com/marketing/v3/emails/statistics/list?startTimestamp=1640995200000
- startTimestamp value: 1640995200000 (Unix timestamp in milliseconds)

**Problems Identified:**
1. The API returns a parsing error even when sending the timestamp in milliseconds format
2. The API documentation lacks specific information about the expected format for the startTimestamp parameter

**Request for Support:**
Could you please provide:
1. The correct format for the startTimestamp parameter (Unix milliseconds, ISO 8601, etc.)
2. Example of a properly formatted request
3. Update the API documentation to include parameter format specifications

This information would help developers implement the endpoint correctly and avoid similar issues.

Thank you for your assistance.

Best regards,
Hirthikraj R

2

Hi @Hirthikraj,
Thank you for posting to the Community!
I’d like to tag in some of our Top Contributors that may have some experience with this endpoint to see if they have any insight regarding this!
Hi @Balaji_Mavlers1 @Anton and @FaramarKolivand Have any of you all utilized the Marketing Email Statistics API endpoint? If so, can you provide some tips on @Hirthikraj’s request above?
Thank you!
Cassie, Community Manager

3

Try using an ISO-8601 format for both ‘startTimestamp’ and ‘endTimestamp’ instead of Unix timestamp in milliseconds.

4

hi @Hirthikraj
The startTimestamp and endTimestamp parameters don’t accept Unix timestamps in milliseconds. Instead, you can use either:
Unix timestamp in seconds → e.g. 1640995200
ISO 8601 format → e.g. 2022-01-01T00:00:00Z
Both can work depending on the API, but if you send milliseconds, it will always give an error.