Date and Time
FutureSMS API timestamps are UTC date-time values. Responses serialize date and time values with the Z suffix, and documented range filters should be sent in the same format.
Timestamp format
Use ISO 8601 UTC strings with a trailing Z.
{
"created_at": "2026-03-25T10:30:00Z",
"updated_at": "2026-03-25T10:31:48Z"
}
| Rule | Meaning |
|---|---|
| Time zone | UTC only. |
| Suffix | Use Z, not a local offset. |
| Date and time separator | Use T. |
| Storage meaning | Returned timestamps describe the platform event time, not the viewer's local time. |
Display conversion belongs in your client. Keep API requests and stored integration state in UTC so retries, reconciliation, and support checks all use the same clock.
Range filters
List endpoints that support time filtering use explicit *_from and *_to parameters.
{
"created_at_from": "2026-04-01T00:00:00Z",
"created_at_to": "2026-04-01T23:59:59Z"
}
| Pattern | Meaning |
|---|---|
created_at_from | Return records created at or after this time. |
created_at_to | Return records created at or before this time. |
updated_at_from | Return records updated at or after this time. |
updated_at_to | Return records updated at or before this time. |
Other timestamp fields follow the same suffix pattern when an endpoint exposes them, such as started_at_from, completed_at_to, or reviewed_at_from.
Common fields
| Field | Typical meaning |
|---|---|
created_at | When the resource or event was first recorded. |
updated_at | When the resource was last changed. |
started_at | When an asynchronous job or process began. |
completed_at | When an asynchronous job or process finished. |
last_attempt_at | When the latest delivery or callback attempt happened. |
Not every endpoint exposes every field. Check the endpoint schema before adding a filter to production traffic.
Validation
Strict UTC endpoints reject ambiguous time values. Send 2026-04-01T00:00:00Z, not 2026-04-01 00:00:00, 2026-04-01T00:00:00+08:00, or a browser-local timestamp.
{
"error_code": "VALIDATION_ERROR",
"reason": null,
"message": "Validation failed",
"details": "datetime must use UTC timezone suffix Z",
"path": "/api/v1/sms/bulk-jobs",
"timestamp": "2026-04-01T00:00:01Z",
"request_id": "req_20260401_demo_0001"
}