Sends a reply email for a thread using the associated draft content. The message is sent via Gmail API and recorded in the database.
Authentication
Requires active session with elevated permissions.
Permission Level: send or admin required
Path Parameters
The unique identifier of the thread to send a reply for
Request Body
No request body required. The endpoint uses the existing draft content stored in the database.
Response
Returns a success confirmation with the Gmail message ID.
Always true when the send operation succeeds
The Gmail message ID returned by the Gmail API, or null if not available
Error Responses
Error message describing what went wrong
send or admin)
{
"error": "Insufficient permissions"
}
{
"error": "thread not found"
}
{
"error": "service account not found"
}
{
"error": "service gmail not connected"
}
{
"error": "draft is empty"
}
{
"error": "already_sent"
}
{
"error": "duplicate_send_blocked"
}
Behavior
Draft Usage
- Uses the draft content and subject stored in the
drafts table for the thread
- If no draft exists, sends an empty message (which will fail validation)
- Draft subject defaults to
Re: {original subject} if not explicitly set
Duplicate Prevention
- Checks if an identical outbound message was sent in the last 90 seconds
- Comparison is done on HTML-stripped content
- Returns
409 duplicate_send_blocked if duplicate detected
Database Updates
The send operation atomically:
- Updates thread status to
sent and marks as read
- Updates or creates draft record with
status: 'sent' and sentAt timestamp
- Inserts a new email record with
direction: 'outbound'
Gmail Integration
- Sends message as HTML MIME email via Gmail API
- Preserves thread continuity using Gmail thread ID
- Uses service account’s email address as sender
Examples
curl -X POST 'https://app.delightbridge.com/api/threads/thread_abc123/send' \
-H 'Cookie: session=...'
Response Example
{
"ok": true,
"gmailMessageId": "18d4f5c6a8b2e9f1"
}
Notes
- This endpoint requires
send or admin permission level, unlike other thread endpoints which allow view or edit
- The draft must have non-empty content (after HTML stripping) to be sent
- Sends are idempotent: if a draft hasn’t been modified since being sent, re-sending returns
already_sent error
- Duplicate detection prevents accidental double-sends within a 90-second window
- The message is sent from the service account’s email address to the thread’s
customerEmail
- All database operations (thread update, draft update, email insert) happen in a transaction