> ## Documentation Index
> Fetch the complete documentation index at: https://docs.sentvia.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Threads & messages

> How SentVia groups a back-and-forth into a single conversation.

A **thread** is one conversation. SentVia reconstructs threads from RFC-5322
headers (`Message-ID`, `In-Reply-To`, `References`), so an exchange between your
agent and a customer stays together — and threads correctly in their mail client too.

## List threads

```bash theme={null}
curl "https://…/v1/threads?inbox_id=INBOX_ID&limit=25" -H "Authorization: Bearer sv_live_…"
```

```json theme={null}
{ "threads": [
  { "id": "t_…", "inbox_id": "…", "subject": "Order #4821", "last_message_at": "2026-06-26T…" }
] }
```

## Read a thread

`GET /threads/{id}` returns the full conversation, oldest first, with bodies and
attachments inlined:

```json theme={null}
{
  "id": "t_…",
  "subject": "Order #4821",
  "messages": [
    { "id": "m_1", "direction": "inbound",  "from_addr": "jane@acme.com",
      "body_text": "Where's my order?", "attachments": [] },
    { "id": "m_2", "direction": "outbound", "from_addr": "support-bot@mail.sentvia.ai",
      "body_text": "On its way — tracking attached.", "attachments": [ … ] }
  ]
}
```

## Single message

`GET /messages/{id}` returns one message with its `delivery_status`, attachments
(with signed URLs), and any [labels](/api-reference/labels/get).

## Keep replies in-thread

When you [reply or forward](/concepts/sending), SentVia sets the threading headers
for you. If you send a fresh `POST /messages` that should join an existing thread,
pass `in_reply_to` (and optionally `references`) from the message you're answering.