diff --git a/hive-c0re/src/audit_log.rs b/hive-c0re/src/audit_log.rs
index 4a64efa7..43f1772a 100644
--- a/hive-c0re/src/audit_log.rs
+++ b/hive-c0re/src/audit_log.rs
@@ -89,6 +89,7 @@ impl AuditOutcome {
 #[derive(Debug, Clone, Serialize)]
 pub struct AuditEntry {
     pub id: i64,
+    #[serde(with = "hive_sh4re::wire_time::iso")]
     pub ts_unix: i64,
     /// Agent on whose behalf the action was taken.
     pub agent: String,
diff --git a/hive-c0re/src/broker.rs b/hive-c0re/src/broker.rs
index b2caef09..aedf314f 100644
--- a/hive-c0re/src/broker.rs
+++ b/hive-c0re/src/broker.rs
@@ -74,7 +74,9 @@ pub struct PendingReminder {
     pub message: String,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub file_path: Option<String>,
+    #[serde(with = "hive_sh4re::wire_time::iso")]
     pub due_at: i64,
+    #[serde(with = "hive_sh4re::wire_time::iso")]
     pub created_at: i64,
     /// Most recent delivery failure for this row, if any. Cleared
     /// to NULL on operator retry. Surfaced inline in the dashboard
diff --git a/hive-c0re/src/dashboard.rs b/hive-c0re/src/dashboard.rs
index 61d8dd49..5a0399e7 100644
--- a/hive-c0re/src/dashboard.rs
+++ b/hive-c0re/src/dashboard.rs
@@ -432,7 +432,8 @@ struct ApprovalHistoryView {
     sha_short: Option<String>,
     /// `approved` / `denied` / `failed`.
     status: &'static str,
-    /// Unix seconds. Renders as a relative time on the dashboard.
+    /// RFC 3339 UTC. Renders as a relative time on the dashboard.
+    #[serde(with = "hive_sh4re::wire_time::iso")]
     resolved_at: i64,
     /// Operator-supplied deny reason (for `denied`) or build error
     /// (for `failed`). None on `approved`.
@@ -471,8 +472,10 @@ struct ApprovalView {
     /// `None` for every other kind.
     #[serde(skip_serializing_if = "Option::is_none")]
     commit_ref: Option<String>,
-    /// Unix seconds the approval was queued. Rendered as a relative
-    /// time on the card so the operator can spot a stale request.
+    /// RFC 3339 UTC time the approval was queued. Rendered as a
+    /// relative time on the card so the operator can spot a stale
+    /// request.
+    #[serde(with = "hive_sh4re::wire_time::iso")]
     requested_at: i64,
 }
 
@@ -1373,7 +1376,7 @@ async fn api_operator_inbox(State(state): State<AppState>) -> Response {
                             "id": id,
                             "from": from,
                             "body": body,
-                            "at": at,
+                            "at": hive_sh4re::wire_time::to_iso(at),
                             "in_reply_to": in_reply_to,
                             "file_refs": file_refs,
                         }))
diff --git a/hive-c0re/src/dashboard_events.rs b/hive-c0re/src/dashboard_events.rs
index 13307bcb..48610473 100644
--- a/hive-c0re/src/dashboard_events.rs
+++ b/hive-c0re/src/dashboard_events.rs
@@ -38,6 +38,7 @@ pub enum DashboardEvent {
         from: String,
         to: String,
         body: String,
+        #[serde(with = "hive_sh4re::wire_time::iso")]
         at: i64,
         #[serde(default, skip_serializing_if = "Option::is_none")]
         in_reply_to: Option<i64>,
@@ -53,6 +54,7 @@ pub enum DashboardEvent {
         from: String,
         to: String,
         body: String,
+        #[serde(with = "hive_sh4re::wire_time::iso")]
         at: i64,
         #[serde(default, skip_serializing_if = "Option::is_none")]
         in_reply_to: Option<i64>,
@@ -95,6 +97,7 @@ pub enum DashboardEvent {
         sha_short: Option<String>,
         /// `"approved"` / `"denied"` / `"failed"`.
         status: &'static str,
+        #[serde(with = "hive_sh4re::wire_time::iso")]
         resolved_at: i64,
         note: Option<String>,
         description: Option<String>,
@@ -111,7 +114,9 @@ pub enum DashboardEvent {
         question: String,
         options: Vec<String>,
         multi: bool,
+        #[serde(with = "hive_sh4re::wire_time::iso")]
         asked_at: i64,
+        #[serde(with = "hive_sh4re::wire_time::iso_opt")]
         deadline_at: Option<i64>,
         target: Option<String>,
         /// Verified file-path tokens that appear in `question`.
@@ -130,6 +135,7 @@ pub enum DashboardEvent {
         id: i64,
         answer: String,
         answerer: String,
+        #[serde(with = "hive_sh4re::wire_time::iso")]
         answered_at: i64,
         cancelled: bool,
         target: Option<String>,
diff --git a/hive-c0re/src/operator_questions.rs b/hive-c0re/src/operator_questions.rs
index 1dcf14ad..ab51e9f0 100644
--- a/hive-c0re/src/operator_questions.rs
+++ b/hive-c0re/src/operator_questions.rs
@@ -74,11 +74,14 @@ pub struct OpQuestion {
     pub question: String,
     pub options: Vec<String>,
     pub multi: bool,
+    #[serde(with = "hive_sh4re::wire_time::iso")]
     pub asked_at: i64,
-    /// Absolute unix-seconds deadline after which a watchdog auto-
-    /// resolves the question with answer `[expired]`. `None` = no
-    /// expiry. Surfaced on the dashboard as a remaining-time chip.
+    /// Deadline after which a watchdog auto-resolves the question with
+    /// answer `[expired]`. `None` = no expiry. Surfaced on the
+    /// dashboard as a remaining-time chip.
+    #[serde(with = "hive_sh4re::wire_time::iso_opt")]
     pub deadline_at: Option<i64>,
+    #[serde(with = "hive_sh4re::wire_time::iso_opt")]
     pub answered_at: Option<i64>,
     pub answer: Option<String>,
     /// Recipient of the question. `None` = the operator (dashboard
diff --git a/hive-sh4re/src/wire_time.rs b/hive-sh4re/src/wire_time.rs
index 680eaa87..cbc3dae7 100644
--- a/hive-sh4re/src/wire_time.rs
+++ b/hive-sh4re/src/wire_time.rs
@@ -16,7 +16,7 @@
 //! (keep the usual `default` + `skip_serializing_if` attributes).
 
 use chrono::{DateTime, SecondsFormat, Utc};
-use serde::{Deserialize, Deserializer};
+use serde::Deserialize;
 
 /// Format unix-epoch seconds as an RFC 3339 UTC string with a `Z`
 /// suffix. Out-of-range values (never produced by our clocks) clamp to