# Message observability

Source: https://joinsimplesms.com/changelog/2026-10-01-message-observability
Index: https://joinsimplesms.com/llms.txt

October 1, 2026

- **Message timeline**: every message records each step with a timestamp
  (`accepted` → `validated` → `queued` → `sent_to_carrier` →
  `carrier_accepted` → `delivered`/`failed`; inbound: `received`) as
  `timeline` on `GET /v1/messages/{id}`.
- **`segments`, `encoding`, `price`, `destination_carrier`** on every message.
- **Readable failures**: failed messages, `message.failed` events, and
  refused sends (opt-out, content block, rate limit, spend limit) carry a
  `failure` object with a stable code, a plain explanation, and what to do.
  See [delivery failures](/docs/errors#delivery-failures).
- **List filters**: `status`, `direction`, `to`, `from`, `created_after`,
  `created_before` (alongside `customer_id`) on `GET /v1/messages`, with
  full pages. Automatic carrier retries show up on the timeline per attempt.
- **Sandbox numbers** for every failure, opt-out, rate limiting, and a really
  delayed delivery. The happy-path number now settles to `delivered` instead of
  staying `sent`.
- **Idempotency-Key** now applies to scheduled sends too.
- **Console**: message filters and a message inspector (timeline latencies,
  cost, failure, related webhook events).