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-code

curl -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": "2026-05-01",
    "to": "2026-05-25",
    "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,
  "next_cursor": "eyJ2IjoxLCJzIjoiXCIyMDI2LTA1LTI1VDE0OjAzOjEwWlwiIiwiaSI6IjAxOTJmM2IxLTRjN2UtN2EyYi05ZDYxLThmM2E1YzJlN2I0MCJ9",
  "prev_cursor": null,
  "refresh_cursor": "eyJ2IjoxLCJzIjoiXCIyMDI2LTA1LTI1VDE2OjQyOjAxWlwiIiwiaSI6IjAxOTJmM2IxLTllMDQtN2NkMy1iODE3LTJhNmY0ZDFjOGUwOSJ9"
}

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 paginated with 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

starting_afterstring

Cursor from the next_cursor field of a previous list response. Returns items immediately after the cursor position in the current sort order.

ending_beforestring

Cursor from the prev_cursor or refresh_cursor field of a previous list response. Returns items immediately before the cursor position in the current sort order. prev_cursor returns the preceding page. refresh_cursor anchors at the first row of that response, which on a newest-first sort is how to fetch the items that have appeared since.

fromstring

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.

tostring

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.

timezonestring

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.

categorystring

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.

sortstring

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

limitinteger

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. Pass next_cursor as starting_after to request the next page.

next_cursor

nullable string

required

Cursor for the next page. Pass back as starting_after to advance forward. null when no next page exists.

prev_cursor

nullable string

required

Cursor for the previous page. Pass back as ending_before to step backward. null when no previous page exists.

refresh_cursor

nullable string

required

Refresh anchor, the first row of this response. Pass back as ending_before to fetch what precedes it in the current sort order. On a newest-first sort those are the items that have appeared since; on any other sort they are the items that sort earlier, so refreshing such a list means re-fetching it instead. Non-null whenever data is non-empty; null only on an empty page. Distinct from prev_cursor.

Continue with the documentation, guides and examples for this topic.

Get an implementation brief

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-code

curl -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": "2026-05-01",
    "to": "2026-05-25",
    "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,
  "next_cursor": "eyJ2IjoxLCJzIjoiXCIyMDI2LTA1LTI1VDE0OjAzOjEwWlwiIiwiaSI6IjAxOTJmM2IxLTRjN2UtN2EyYi05ZDYxLThmM2E1YzJlN2I0MCJ9",
  "prev_cursor": null,
  "refresh_cursor": "eyJ2IjoxLCJzIjoiXCIyMDI2LTA1LTI1VDE2OjQyOjAxWlwiIiwiaSI6IjAxOTJmM2IxLTllMDQtN2NkMy1iODE3LTJhNmY0ZDFjOGUwOSJ9"
}

Get bounces by SMTP error code

Query Parameters

Response Payload

Related resources