Get bounces by SMTP error code
GET
/v1/email/stats/bounce-codes
const { data } = await bird.email.stats.byBounceCode({
from: "2026-05-01",
to: "2026-05-31",
sort: "bounced",
limit: 25,
});
for (const row of data) console.log(row.smtp_error_code, row.bounced);stats = client.email.stats.by_bounce_code(from_="2026-05-01", to="2026-05-25")
for row in stats.data:
print(row)stats, err := client.Email.Stats.ByBounceCode(context.Background(), bird.EmailStatsByBounceCodeParams{})
if err != nil {
log.Fatal(err)
}
fmt.Println(stats.Data)$stats = $bird->email->stats->byBounceCode([
'from' => '2026-05-01',
'to' => '2026-05-31',
'sort' => 'bounced',
'limit' => 25,
]);
foreach ($stats->getData() ?? [] as $row) {
echo $row->getSmtpErrorCode(), ' ', $row->getBounced(), "\n";
}bird email stats by-bounce-codecurl -X GET "https://us1.platform.bird.com/v1/email/stats/bounce-codes" \
-H "Authorization: Bearer $TOKEN" \
--url-query "sort=bounced" \
--url-query "limit=50"Response200
{
"period": {
"from": "2026-05-01T00:00:00Z",
"to": "2026-05-25T00:00:00Z",
"data_as_of": "2026-05-25T14:03:10Z"
},
"data": [
{
"smtp_error_code": "5.1.1",
"bounced": 1240,
"bounces": {
"hard": 42,
"soft": 48,
"admin": 4,
"block": 6,
"undetermined": 1
}
}
],
"total": 17
}
Returns bounce counts for the requested period, grouped by the SMTP error code the receiving mail server returned. It answers the question of which SMTP responses are driving your bounces. Each row reports how many recipients bounced with that code, plus the hard, soft, admin, block, and undetermined split for that code.
This failure-only breakdown omits delivered, open, click, and rate fields because bounce codes occur only on bounce events.
Rows are ranked by the sort metric, bounced by default, and capped at the requested limit (50 by default, 200 at most). They are computed against event time rather than send time. The window can span at most 365 days. Ask for more and you get a 422.
Query Parameters
from
string
Start date (inclusive) in YYYY-MM-DD, interpreted as a calendar day in timezone (a UTC day when timezone is omitted). Defaults to 30 days before to when omitted.
to
string
End date (inclusive) in YYYY-MM-DD, interpreted as a calendar day in timezone (a UTC day when timezone is omitted). Defaults to today in that timezone when omitted. Window may not exceed 365 days.
timezone
string
IANA timezone identifier used to group statistics, for example Asia/Kathmandu. The default is UTC. Day and hour boundaries, including the default window when from and to are omitted, follow this timezone. When this parameter is set, pass from and to as calendar days or Z instants instead of timestamps with explicit UTC offsets.
category
string
Not supported on breakdown endpoints. Supplying it returns 422. To compare categories, use GET /v1/email/stats/categories. The summary, daily, and hourly statistics accept category as a filter.
sort
string
Metric to rank rows by, applied descending. It defaults to bounced. Only the bounce counts are sortable here, because this breakdown has no rate fields.
Possible values: bounced, bounces.hard, bounces.soft, bounces.admin, bounces.block, bounces.undetermined
limit
integer
Maximum number of bounce-code rows to return, ranked by the sort field descending.
Response Payload
period
object
required
The date range the response covers (echoed back from the request), plus data_as_of, the freshness boundary the data is current to.
Show child attributes
period.from
string
required
Inclusive start date the response covers (YYYY-MM-DD).
period.to
string
required
Inclusive end date the response covers (YYYY-MM-DD).
period.data_as_of
nullable string
The instant the statistics in this response are current to: events recorded up to roughly this time are reflected, while more recent events may not be yet. Statistics are served from a rolling aggregation that refreshes every few seconds, so a response reflects data from up to a few seconds ago. Use this field to label data freshness (for example "as of 14:03") rather than assuming the numbers are to-the-second. Null when the freshness boundary is not being reported.
data
array of object
required
Bounce-code breakdown rows, ranked by the sort metric (default bounced) descending. Empty when no bounces occurred in the period.
Show child attributes
data.smtp_error_code
string
required
The SMTP error code the receiving mail server returned for these bounces, as reported by that server (for example 5.1.1 for an unknown recipient, 4.2.2 for a full mailbox). The form varies by server, and the set of codes is open.
data.bounced
integer
required
Distinct recipients whose delivery failed with this SMTP status code, approximately equal to the sum of the five bounces.* sub-counts. The two are computed independently, so they can differ slightly because of approximation.
data.bounces
object
required
Show child attributes
data.bounces.hard
integer
required
Distinct recipients with a permanent delivery failure (invalid address or non-existent domain). The address is automatically added to the suppression list.
data.bounces.soft
integer
required
Distinct recipients with a transient delivery failure (mailbox full or server temporarily unavailable). Delivery was retried.
data.bounces.admin
integer
required
Distinct recipients refused by a policy at the receiving end, such as relaying denied or a blocklisted domain. Fix these by changing your content or sender configuration. Cleaning the recipient list does not usually help.
data.bounces.block
integer
required
Distinct recipients bounced because the receiving mail server blocked the sending IP for reputation reasons (mail block, spam block, spam content). Triage usually focuses on IP reputation and sending volume.
data.bounces.undetermined
integer
required
Distinct recipients bounced where the receiving server's response did not allow precise classification.
total
integer
required
Total number of distinct SMTP error codes with activity in the period, regardless of limit. When it exceeds the number of rows returned, the ranking was capped. Raise limit (up to 200) or narrow the window to see more.