diff --git a/engine/packages/pegboard/src/ops/runner_config/upsert.rs b/engine/packages/pegboard/src/ops/runner_config/upsert.rs
index 51eb91ff94..094b68e16c 100644
--- a/engine/packages/pegboard/src/ops/runner_config/upsert.rs
+++ b/engine/packages/pegboard/src/ops/runner_config/upsert.rs
@@ -29,6 +29,7 @@ pub async fn pegboard_runner_config_upsert(ctx: &OperationCtx, input: &Input) ->
 		RunnerConfigKind::Serverless {
 			url,
 			headers,
+			request_lifespan,
 			drain_grace_period,
 			slots_per_runner,
 			..
@@ -81,6 +82,15 @@ pub async fn pegboard_runner_config_upsert(ctx: &OperationCtx, input: &Input) ->
 				.build());
 			}
 
+			if *drain_grace_period >= *request_lifespan {
+				return Err(errors::RunnerConfig::Invalid {
+					reason: format!(
+						"`drain_grace_period` must be less than `request_lifespan` ({drain_grace_period}s >= {request_lifespan}s)"
+					),
+				}
+				.build());
+			}
+
 			let actor_stop_threshold_ms = ctx.config().pegboard().actor_stop_threshold();
 			let drain_grace_period_ms = i64::from(*drain_grace_period) * 1000;
 			if drain_grace_period_ms > actor_stop_threshold_ms {