--- title: "Get aggregate email statistics" canonical: "https://bird.com/docs/api/reference/get-email-stats-summary" --- # Get aggregate email statistics `GET /v1/email/stats/summary` Returns a single-row aggregate across the requested period covering delivery, bounce, complaint, open, and click counts plus the derived rates, along with processing, delivery, and total latency percentiles (p50/p95/p99). Suitable for KPI tiles, campaign reports, and email digests; the daily and hourly endpoints have the same metrics per time bucket. The aggregate is computed against event time (not send time), so engagement received during the period for messages sent earlier is included. Rate fields are `null` when their denominator is zero. The window grain follows the form of `from` and `to`: calendar days (`YYYY-MM-DD`, up to 365 days) or RFC 3339 instants (hour grain, up to 720 hours, 30 days). A rolling window such as the last 24 hours is a single request. Mixing the two forms returns `422`. Set `timezone` to compute day and hour boundaries in a local zone instead of UTC, and `compare=previous_period` to include the preceding equal-length window in the same response. ## Code samples **TypeScript** ```ts const s = await bird.email.stats.summary({ from: "2026-05-01", to: "2026-05-31" }); console.log(s.sends_accepted, s.delivery.delivered); ``` Examples: [TypeScript](/docs/api/reference/get-email-stats-summary.ts.md) · [Python](/docs/api/reference/get-email-stats-summary.py.md) · [Go](/docs/api/reference/get-email-stats-summary.go.md) · [PHP](/docs/api/reference/get-email-stats-summary.php.md) · [CLI](/docs/api/reference/get-email-stats-summary.cli.md) · [MCP](/docs/api/reference/get-email-stats-summary.mcp.md) · [cURL](/docs/api/reference/get-email-stats-summary.curl.md) ## Example response `200` ```json { "period": { "from": "2026-05-01", "to": "2026-05-25", "data_as_of": "2026-05-25T14:03:10Z" }, "sends_accepted": 12410, "delivery": { "accepted": 14820, "processed": 14810, "delivered": 14720, "bounced": 90, "bounces": { "hard": 12410, "soft": 14290, "admin": 410, "block": 920, "undetermined": 80, "hard_rate": 0.454, "soft_rate": 0.523, "admin_rate": 0.015, "block_rate": 0.0337, "undetermined_rate": 0.0029 }, "complained": 3, "deferred": 14, "rejected": 10, "oob_bounces": 2, "effective_delivered": 14718, "all_bounces": 92, "oob_rate": 0.00014, "delivery_rate": 0.9939, "bounce_rate": 0.0061, "complaint_rate": 0.0002 }, "engagement": { "opens": 5420, "opens_non_prefetched": 3210, "unique_opens": 3640, "unique_opens_non_prefetched": 2480, "clicks": 924, "unique_clicks": 621, "unsubscribes": 12, "open_rate": 0.1683, "click_rate": 0.0422, "unsubscribe_rate": 0.0009 }, "latency": { "processing": { "p50_ms": 420, "p95_ms": 1820, "p99_ms": 4920 }, "delivery": { "p50_ms": 420, "p95_ms": 1820, "p99_ms": 4920 }, "total": { "p50_ms": 420, "p95_ms": 1820, "p99_ms": 4920 } }, "comparison": { "period": { "from": "2026-05-01", "to": "2026-05-25", "data_as_of": "2026-05-25T14:03:10Z" }, "sends_accepted": 8230, "delivery": { "accepted": 14820, "processed": 14810, "delivered": 14720, "bounced": 90, "bounces": { "hard": 12410, "soft": 14290, "admin": 410, "block": 920, "undetermined": 80, "hard_rate": 0.454, "soft_rate": 0.523, "admin_rate": 0.015, "block_rate": 0.0337, "undetermined_rate": 0.0029 }, "complained": 3, "deferred": 14, "rejected": 10, "oob_bounces": 2, "effective_delivered": 14718, "all_bounces": 92, "oob_rate": 0.00014, "delivery_rate": 0.9939, "bounce_rate": 0.0061, "complaint_rate": 0.0002 }, "engagement": { "opens": 5420, "opens_non_prefetched": 3210, "unique_opens": 3640, "unique_opens_non_prefetched": 2480, "clicks": 924, "unique_clicks": 621, "unsubscribes": 12, "open_rate": 0.1683, "click_rate": 0.0422, "unsubscribe_rate": 0.0009 }, "latency": { "processing": { "p50_ms": 420, "p95_ms": 1820, "p99_ms": 4920 }, "delivery": { "p50_ms": 420, "p95_ms": 1820, "p99_ms": 4920 }, "total": { "p50_ms": 420, "p95_ms": 1820, "p99_ms": 4920 } }, "delta": { "sends_accepted_pct_change": 0.508, "delivered_pct_change": 0.122, "bounced_pct_change": -0.031, "complained_pct_change": 0.018, "opened_pct_change": -0.046, "delivery_rate_pp": 0.004, "open_rate_pp": 0.005, "click_rate_pp": 0.002, "bounce_rate_pp": -0.0008, "complaint_rate_pp": 0.0001, "unsubscribe_rate_pp": -0.0001 } } } ``` ## Query parameters - `from` (string): Inclusive start of the window: a calendar day (`YYYY-MM-DD`) or an RFC 3339 instant (rounded down to the hour). Interpreted in `timezone` (a calendar day names a local day; an instant is rounded down to the local hour), or in UTC when `timezone` is omitted. A numeric UTC offset (for example `+05:45`) is rejected when `timezone` is set; use a calendar day or a `Z` (UTC) instant. Must use the same form as `to`. Defaults to 30 days before `to` for day windows, or 168 hours (7 days) before `to` for hour windows, when omitted. - `to` (string): Inclusive end of the window: a calendar day (`YYYY-MM-DD`) or an RFC 3339 instant (rounded down to the hour). Interpreted in `timezone` (a calendar day names a local day; an instant is rounded down to the local hour), or in UTC when `timezone` is omitted. A numeric UTC offset is rejected when `timezone` is set; use a calendar day or a `Z` (UTC) instant. Must use the same form as `from`. Defaults to today for day windows, or the current hour for hour windows, in that timezone, when omitted. Day windows may not exceed 365 days; hour windows may not exceed 720 hours (30 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): Restrict the statistics to a category or a comma-separated union of categories: `transactional` or `marketing`. Mutually exclusive with the other dimension filters; only one may be set per request. - `sending_domain` (string): Restrict the statistics to a sending domain or a comma-separated union of sending domains (the part of the From address after @). Mutually exclusive with the other dimension filters; only one may be set per request. - `tag` (string): Restrict the statistics to a tag. Use `name` to match any value of a tag, or `name:value` for a specific pair (for example `campaign:spring_launch`). To combine values of one tag name, separate complete pairs with commas, such as `campaign:spring,campaign:summer`. Different tag names cannot be combined. Mutually exclusive with the other dimension filters; only one may be set per request. - `sending_ip` (string): Restrict the statistics to a sending IP or a comma-separated union of IPs. Mutually exclusive with the other dimension filters; only one may be set per request. A sending IP is assigned only after a message reaches delivery, so this filter reports delivery-side metrics only. Accepted, processed, rejected, complaint, and engagement counts are `0`, and processing latency is `null`. Complaint, open, and click rates are `0` when deliveries exist and `null` otherwise. - `recipient_domain` (string): Restrict the statistics to a recipient mailbox domain or a comma-separated union of domains (the part of the recipient address after the `@`, for example `gmail.com`). Mutually exclusive with the other dimension filters; only one may be set per request. - `template` (string): Restricts the statistics to a template or a comma-separated union of templates, identified by ID (`emt_…`) or name. This parameter is mutually exclusive with other dimension filters. - `compare` (string) Set to `previous_period` to also include the same statistics for the immediately preceding window of equal length, plus the change between the two, so you can show "+X% vs last period" without a second request. Possible values: `previous_period` ## Response body - `period` (object, required): The window the response covers (echoed back from the request, day or hour grain), plus `data_as_of`, the freshness boundary the data is current to. - `period.from` (string, required): Inclusive start of the window the response covers. A calendar day (YYYY-MM-DD, in the requested `timezone`) for day windows. For hour windows, an RFC 3339 UTC instant marking the start of the first hour, which falls on a local hour boundary when `timezone` is set. - `period.to` (string, required): Inclusive end of the window the response covers. A calendar day (YYYY-MM-DD, in the requested `timezone`) for day windows. For hour windows, an RFC 3339 UTC instant marking the start of the last hour, which falls on a local hour boundary when `timezone` is set. - `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. - `sends_accepted` (integer, required): Distinct email messages accepted, counted at the message level (one per accepted send regardless of recipient count) across the whole requested period. This field counts messages. `delivery.accepted` counts recipients, so the two values are not comparable (a single message to 500 recipients is 1 here and up to 500 there). - `delivery` (object, required) - `delivery.accepted` (integer): Distinct recipients accepted for delivery after suppression filtering. Reported on time buckets and the period summary. Breakdown rows leave it out, because their rollups do not have it. - `delivery.processed` (integer, required): Distinct recipients whose message was processed and handed off for delivery. - `delivery.delivered` (integer, required): Distinct recipients whose message the receiving mail server accepted. - `delivery.bounced` (integer, required): Distinct recipients whose delivery failed. This is approximately the sum of the five `bounces.*` sub-counts (hard, soft, admin, block, undetermined). The two totals are worked out independently, so they can differ slightly. - `delivery.bounces` (object, required) - `delivery.bounces.hard` (integer, required): Distinct recipients with a permanent delivery failure (invalid address or non-existent domain). - `delivery.bounces.soft` (integer, required): Distinct recipients with a transient delivery failure (mailbox full or server temporarily unavailable). - `delivery.bounces.admin` (integer, required): Distinct recipients refused by a policy at the receiving end, such as relaying denied or a blocklisted domain. - `delivery.bounces.block` (integer, required): Distinct recipients bounced because the receiving mail server blocked the sending IP for reputation reasons. - `delivery.bounces.undetermined` (integer, required): Distinct recipients bounced where the receiving server's response did not allow precise classification. - `delivery.bounces.hard_rate` (nullable number, required): Fraction of bounced recipients that hard bounced, computed as `hard / bounced`. Null when `bounced` is zero. - `delivery.bounces.soft_rate` (nullable number, required): Fraction of bounced recipients that soft bounced, computed as `soft / bounced`. Null when `bounced` is zero. - `delivery.bounces.admin_rate` (nullable number, required): Fraction of bounced recipients that admin bounced, computed as `admin / bounced`. Null when `bounced` is zero. - `delivery.bounces.block_rate` (nullable number, required): Fraction of bounced recipients that block bounced, computed as `block / bounced`. Null when `bounced` is zero. - `delivery.bounces.undetermined_rate` (nullable number, required): Fraction of bounced recipients with undetermined classification, computed as `undetermined / bounced`. Null when `bounced` is zero. - `delivery.complained` (integer, required): Distinct recipients who reported the message as spam via a feedback loop. - `delivery.deferred` (integer, required): Distinct recipients whose delivery the receiving server temporarily delayed and is still being retried. - `delivery.rejected` (integer, required): Distinct recipients rejected before any delivery attempt. Includes recipients on the workspace suppression list, transmissions that could not be completed, message-generation failures, and recipients refused by sending policy. The per-recipient `rejection_reason` field on `GET /v1/email/messages/{message_id}/recipients` surfaces the specific cause. - `delivery.oob_bounces` (integer, required): Out-of-band bounce events: distinct failure notifications received after the receiving server had initially confirmed delivery. The count represents deduplicated events rather than unique recipients. - `delivery.effective_delivered` (integer, required): Recipients who remain delivered after all bounce signals resolve, computed as `delivered - oob_bounces`. Use this as the base for engagement-rate denominators. Clamped to 0 when `oob_bounces` exceeds `delivered`. - `delivery.all_bounces` (integer, required): Total recipients in this scope who did not receive the message, computed as `bounced + oob_bounces`. - `delivery.oob_rate` (nullable number, required): Share of this scope's delivery attempts that resulted in an out-of-band bounce, computed as `oob_bounces / (delivered + bounced)`. Null when there were no attempts. - `delivery.delivery_rate` (nullable number, required): Share of this scope's delivery attempts that remained delivered after all bounce signals, computed as `effective_delivered / (delivered + bounced)`. Null when there were no attempts. - `delivery.bounce_rate` (nullable number, required): Share of this scope's delivery attempts that ultimately failed (inband or out-of-band), computed as `all_bounces / (delivered + bounced)`. Because `oob_bounces` counts events rather than recipients, `all_bounces` can exceed the attempt count. The rate is clamped to 1. Null when there were no attempts. - `delivery.complaint_rate` (nullable number, required): Spam complaints in this scope relative to effectively delivered recipients, computed as `complained / effective_delivered`. Complaints are attributed by event time, so a scope can record more of them than it effectively delivered, pushing the rate above 1. Null when `effective_delivered` is zero. - `engagement` (object, required) - `engagement.opens` (integer, required): Distinct open events, counting repeat opens from the same recipient and opens auto-fetched by inbox privacy features (such as Apple Mail Privacy Protection and the Gmail image proxy). - `engagement.opens_non_prefetched` (integer, required): Distinct open events excluding those auto-fetched by inbox privacy features. Same event-counting semantics as `opens` (repeat opens from the same recipient count separately), with prefetched opens removed. - `engagement.unique_opens` (integer, required): Distinct recipients who opened at least once, including opens auto-fetched by inbox privacy features. - `engagement.unique_opens_non_prefetched` (integer, required): Distinct recipients who opened at least once, excluding opens auto-fetched by inbox privacy features. This is the numerator used for open rate, so iOS-heavy audiences (Apple Mail Privacy Protection and similar) do not inflate it. - `engagement.clicks` (integer, required): Distinct click events, counting repeat clicks from the same recipient. - `engagement.unique_clicks` (integer, required): Distinct recipients who clicked at least once. - `engagement.unsubscribes` (integer, required): Distinct unsubscribe events, recorded via the list-unsubscribe header or the footer link. - `engagement.open_rate` (nullable number, required): Distinct non-prefetched openers relative to effectively delivered recipients in the same scope, computed as `unique_opens_non_prefetched / delivery.effective_delivered`; on rows without an `effective_delivered` field (the mailbox-provider breakdowns) the denominator equals `delivery.delivered`. The numerator excludes opens auto-fetched by inbox privacy features. Opens are attributed by event time, so engagement earned by earlier deliveries can push the rate above 1. Null when the denominator is zero. - `engagement.click_rate` (nullable number, required): Distinct clickers relative to effectively delivered recipients in the same scope, computed as `unique_clicks / delivery.effective_delivered` (`delivery.delivered` on rows without an `effective_delivered` field). Clicks are attributed by event time, so engagement earned by earlier deliveries can push the rate above 1. Null when the denominator is zero. - `engagement.unsubscribe_rate` (nullable number, required): Unsubscribe events relative to effectively delivered recipients in the same scope, computed as `unsubscribes / delivery.effective_delivered` (`delivery.delivered` on rows without an `effective_delivered` field). Unsubscribes are attributed by event time, so the rate can exceed 1. Null when the denominator is zero. - `latency` (object, required) - `latency.processing` (object): Approximate p50, p95, and p99 latency percentiles in milliseconds for one latency family over the bucket. All three are null when no qualifying event contributed a measurement. - `latency.processing.p50_ms` (nullable integer, required): Median (50th percentile) latency in milliseconds. Null when no qualifying event contributed a measurement. - `latency.processing.p95_ms` (nullable integer, required): 95th percentile latency in milliseconds. Null when no qualifying event contributed a measurement. - `latency.processing.p99_ms` (nullable integer, required): 99th percentile latency in milliseconds. Null when no qualifying event contributed a measurement. - `latency.delivery` (object): Approximate p50, p95, and p99 latency percentiles in milliseconds for one latency family over the bucket. All three are null when no qualifying event contributed a measurement. - `latency.delivery.p50_ms` (nullable integer, required): Median (50th percentile) latency in milliseconds. Null when no qualifying event contributed a measurement. - `latency.delivery.p95_ms` (nullable integer, required): 95th percentile latency in milliseconds. Null when no qualifying event contributed a measurement. - `latency.delivery.p99_ms` (nullable integer, required): 99th percentile latency in milliseconds. Null when no qualifying event contributed a measurement. - `latency.total` (object): Approximate p50, p95, and p99 latency percentiles in milliseconds for one latency family over the bucket. All three are null when no qualifying event contributed a measurement. - `latency.total.p50_ms` (nullable integer, required): Median (50th percentile) latency in milliseconds. Null when no qualifying event contributed a measurement. - `latency.total.p95_ms` (nullable integer, required): 95th percentile latency in milliseconds. Null when no qualifying event contributed a measurement. - `latency.total.p99_ms` (nullable integer, required): 99th percentile latency in milliseconds. Null when no qualifying event contributed a measurement. - `comparison` (object) - `comparison.period` (object, required): The preceding window these comparison figures cover, the equal-length window ending immediately before the requested start (the prior day for day windows, the prior hour for hour windows). For a request covering 2026-05-01 to 2026-05-31, this is 2026-03-31 to 2026-04-30, both inclusive. - `comparison.period.from` (string, required): Inclusive start of the window the response covers. A calendar day (YYYY-MM-DD, in the requested `timezone`) for day windows. For hour windows, an RFC 3339 UTC instant marking the start of the first hour, which falls on a local hour boundary when `timezone` is set. - `comparison.period.to` (string, required): Inclusive end of the window the response covers. A calendar day (YYYY-MM-DD, in the requested `timezone`) for day windows. For hour windows, an RFC 3339 UTC instant marking the start of the last hour, which falls on a local hour boundary when `timezone` is set. - `comparison.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. - `comparison.sends_accepted` (integer, required): Distinct email messages accepted in the preceding period, counted at the message level. - `comparison.delivery` (object, required) - `comparison.delivery.accepted` (integer): Distinct recipients accepted for delivery after suppression filtering. Reported on time buckets and the period summary. Breakdown rows leave it out, because their rollups do not have it. - `comparison.delivery.processed` (integer, required): Distinct recipients whose message was processed and handed off for delivery. - `comparison.delivery.delivered` (integer, required): Distinct recipients whose message the receiving mail server accepted. - `comparison.delivery.bounced` (integer, required): Distinct recipients whose delivery failed. This is approximately the sum of the five `bounces.*` sub-counts (hard, soft, admin, block, undetermined). The two totals are worked out independently, so they can differ slightly. - `comparison.delivery.bounces` (object, required) - `comparison.delivery.bounces.hard` (integer, required): Distinct recipients with a permanent delivery failure (invalid address or non-existent domain). - `comparison.delivery.bounces.soft` (integer, required): Distinct recipients with a transient delivery failure (mailbox full or server temporarily unavailable). - `comparison.delivery.bounces.admin` (integer, required): Distinct recipients refused by a policy at the receiving end, such as relaying denied or a blocklisted domain. - `comparison.delivery.bounces.block` (integer, required): Distinct recipients bounced because the receiving mail server blocked the sending IP for reputation reasons. - `comparison.delivery.bounces.undetermined` (integer, required): Distinct recipients bounced where the receiving server's response did not allow precise classification. - `comparison.delivery.bounces.hard_rate` (nullable number, required): Fraction of bounced recipients that hard bounced, computed as `hard / bounced`. Null when `bounced` is zero. - `comparison.delivery.bounces.soft_rate` (nullable number, required): Fraction of bounced recipients that soft bounced, computed as `soft / bounced`. Null when `bounced` is zero. - `comparison.delivery.bounces.admin_rate` (nullable number, required): Fraction of bounced recipients that admin bounced, computed as `admin / bounced`. Null when `bounced` is zero. - `comparison.delivery.bounces.block_rate` (nullable number, required): Fraction of bounced recipients that block bounced, computed as `block / bounced`. Null when `bounced` is zero. - `comparison.delivery.bounces.undetermined_rate` (nullable number, required): Fraction of bounced recipients with undetermined classification, computed as `undetermined / bounced`. Null when `bounced` is zero. - `comparison.delivery.complained` (integer, required): Distinct recipients who reported the message as spam via a feedback loop. - `comparison.delivery.deferred` (integer, required): Distinct recipients whose delivery the receiving server temporarily delayed and is still being retried. - `comparison.delivery.rejected` (integer, required): Distinct recipients rejected before any delivery attempt. Includes recipients on the workspace suppression list, transmissions that could not be completed, message-generation failures, and recipients refused by sending policy. The per-recipient `rejection_reason` field on `GET /v1/email/messages/{message_id}/recipients` surfaces the specific cause. - `comparison.delivery.oob_bounces` (integer, required): Out-of-band bounce events: distinct failure notifications received after the receiving server had initially confirmed delivery. The count represents deduplicated events rather than unique recipients. - `comparison.delivery.effective_delivered` (integer, required): Recipients who remain delivered after all bounce signals resolve, computed as `delivered - oob_bounces`. Use this as the base for engagement-rate denominators. Clamped to 0 when `oob_bounces` exceeds `delivered`. - `comparison.delivery.all_bounces` (integer, required): Total recipients in this scope who did not receive the message, computed as `bounced + oob_bounces`. - `comparison.delivery.oob_rate` (nullable number, required): Share of this scope's delivery attempts that resulted in an out-of-band bounce, computed as `oob_bounces / (delivered + bounced)`. Null when there were no attempts. - `comparison.delivery.delivery_rate` (nullable number, required): Share of this scope's delivery attempts that remained delivered after all bounce signals, computed as `effective_delivered / (delivered + bounced)`. Null when there were no attempts. - `comparison.delivery.bounce_rate` (nullable number, required): Share of this scope's delivery attempts that ultimately failed (inband or out-of-band), computed as `all_bounces / (delivered + bounced)`. Because `oob_bounces` counts events rather than recipients, `all_bounces` can exceed the attempt count. The rate is clamped to 1. Null when there were no attempts. - `comparison.delivery.complaint_rate` (nullable number, required): Spam complaints in this scope relative to effectively delivered recipients, computed as `complained / effective_delivered`. Complaints are attributed by event time, so a scope can record more of them than it effectively delivered, pushing the rate above 1. Null when `effective_delivered` is zero. - `comparison.engagement` (object, required) - `comparison.engagement.opens` (integer, required): Distinct open events, counting repeat opens from the same recipient and opens auto-fetched by inbox privacy features (such as Apple Mail Privacy Protection and the Gmail image proxy). - `comparison.engagement.opens_non_prefetched` (integer, required): Distinct open events excluding those auto-fetched by inbox privacy features. Same event-counting semantics as `opens` (repeat opens from the same recipient count separately), with prefetched opens removed. - `comparison.engagement.unique_opens` (integer, required): Distinct recipients who opened at least once, including opens auto-fetched by inbox privacy features. - `comparison.engagement.unique_opens_non_prefetched` (integer, required): Distinct recipients who opened at least once, excluding opens auto-fetched by inbox privacy features. This is the numerator used for open rate, so iOS-heavy audiences (Apple Mail Privacy Protection and similar) do not inflate it. - `comparison.engagement.clicks` (integer, required): Distinct click events, counting repeat clicks from the same recipient. - `comparison.engagement.unique_clicks` (integer, required): Distinct recipients who clicked at least once. - `comparison.engagement.unsubscribes` (integer, required): Distinct unsubscribe events, recorded via the list-unsubscribe header or the footer link. - `comparison.engagement.open_rate` (nullable number, required): Distinct non-prefetched openers relative to effectively delivered recipients in the same scope, computed as `unique_opens_non_prefetched / delivery.effective_delivered`; on rows without an `effective_delivered` field (the mailbox-provider breakdowns) the denominator equals `delivery.delivered`. The numerator excludes opens auto-fetched by inbox privacy features. Opens are attributed by event time, so engagement earned by earlier deliveries can push the rate above 1. Null when the denominator is zero. - `comparison.engagement.click_rate` (nullable number, required): Distinct clickers relative to effectively delivered recipients in the same scope, computed as `unique_clicks / delivery.effective_delivered` (`delivery.delivered` on rows without an `effective_delivered` field). Clicks are attributed by event time, so engagement earned by earlier deliveries can push the rate above 1. Null when the denominator is zero. - `comparison.engagement.unsubscribe_rate` (nullable number, required): Unsubscribe events relative to effectively delivered recipients in the same scope, computed as `unsubscribes / delivery.effective_delivered` (`delivery.delivered` on rows without an `effective_delivered` field). Unsubscribes are attributed by event time, so the rate can exceed 1. Null when the denominator is zero. - `comparison.latency` (object, required) - `comparison.latency.processing` (object): Approximate p50, p95, and p99 latency percentiles in milliseconds for one latency family over the bucket. All three are null when no qualifying event contributed a measurement. - `comparison.latency.processing.p50_ms` (nullable integer, required): Median (50th percentile) latency in milliseconds. Null when no qualifying event contributed a measurement. - `comparison.latency.processing.p95_ms` (nullable integer, required): 95th percentile latency in milliseconds. Null when no qualifying event contributed a measurement. - `comparison.latency.processing.p99_ms` (nullable integer, required): 99th percentile latency in milliseconds. Null when no qualifying event contributed a measurement. - `comparison.latency.delivery` (object): Approximate p50, p95, and p99 latency percentiles in milliseconds for one latency family over the bucket. All three are null when no qualifying event contributed a measurement. - `comparison.latency.delivery.p50_ms` (nullable integer, required): Median (50th percentile) latency in milliseconds. Null when no qualifying event contributed a measurement. - `comparison.latency.delivery.p95_ms` (nullable integer, required): 95th percentile latency in milliseconds. Null when no qualifying event contributed a measurement. - `comparison.latency.delivery.p99_ms` (nullable integer, required): 99th percentile latency in milliseconds. Null when no qualifying event contributed a measurement. - `comparison.latency.total` (object): Approximate p50, p95, and p99 latency percentiles in milliseconds for one latency family over the bucket. All three are null when no qualifying event contributed a measurement. - `comparison.latency.total.p50_ms` (nullable integer, required): Median (50th percentile) latency in milliseconds. Null when no qualifying event contributed a measurement. - `comparison.latency.total.p95_ms` (nullable integer, required): 95th percentile latency in milliseconds. Null when no qualifying event contributed a measurement. - `comparison.latency.total.p99_ms` (nullable integer, required): 99th percentile latency in milliseconds. Null when no qualifying event contributed a measurement. - `comparison.delta` (object, required) - `comparison.delta.sends_accepted_pct_change` (nullable number, required): Relative change in accepted messages (the `sends_accepted` count) versus the previous period, as a signed fraction. Null when the previous period accepted none. - `comparison.delta.delivered_pct_change` (nullable number, required): Relative change in effectively delivered recipients (`delivery.effective_delivered`, the delivery-rate numerator) versus the previous period, as a signed fraction. Null when the previous period effectively delivered none. - `comparison.delta.bounced_pct_change` (nullable number, required): Relative change in total bounces including out-of-band (`delivery.all_bounces`, the bounce-rate numerator) versus the previous period, as a signed fraction. Null when the previous period had none. - `comparison.delta.complained_pct_change` (nullable number, required): Relative change in spam complaints (`delivery.complained`) versus the previous period, as a signed fraction. Null when the previous period had none. - `comparison.delta.opened_pct_change` (nullable number, required): Relative change in unique non-prefetched opens (`engagement.unique_opens_non_prefetched`, the same count the open rate uses) versus the previous period, as a signed fraction. Null when the previous period had none. - `comparison.delta.delivery_rate_pp` (nullable number, required): Signed difference between this period's and the previous period's delivery rate, both fractions in [0,1] (multiply by 100 for percentage points). Null when either period's delivery rate is undefined. - `comparison.delta.open_rate_pp` (nullable number, required): Signed difference between this period's and the previous period's open rate, both fractions (multiply by 100 for percentage points). Null when either period's open rate is undefined. - `comparison.delta.click_rate_pp` (nullable number, required): Signed difference between this period's and the previous period's click rate, both fractions (multiply by 100 for percentage points). Null when either period's click rate is undefined. - `comparison.delta.bounce_rate_pp` (nullable number, required): Signed difference between this period's and the previous period's bounce rate, both fractions in [0,1] (multiply by 100 for percentage points). Null when either period's bounce rate is undefined. - `comparison.delta.complaint_rate_pp` (nullable number, required): Signed difference between this period's and the previous period's complaint rate, both fractions (multiply by 100 for percentage points). Null when either period's complaint rate is undefined. - `comparison.delta.unsubscribe_rate_pp` (nullable number, required): Signed difference between this period's and the previous period's unsubscribe rate, both fractions (multiply by 100 for percentage points). Null when either period's unsubscribe rate is undefined. ## Related resources - [What is click-through rate for email and SMS?](/explained/engagement/what-is-click-through-rate) (answer) - [Email analytics](/email-api/features/analytics) (product) - [Email metrics](/docs/guides/email/tracking-and-metrics) (docs) [Get an implementation brief](/learn/workspace?topic=email-metrics)