diff --git a/infrastructure/terraform/lambda/_template/main.tf b/infrastructure/terraform/lambda/_template/main.tf
index 81b1c7f1..1cd63ffe 100644
--- a/infrastructure/terraform/lambda/_template/main.tf
+++ b/infrastructure/terraform/lambda/_template/main.tf
@@ -36,6 +36,8 @@ module "lambda" {
   # Optional: Set maximum_concurrency to limit concurrent SQS-triggered invocations (2-1000)
   maximum_concurrency = var.maximum_concurrency
 
+  reserved_concurrent_executions = var.reserved_concurrent_executions
+
   batch_size = var.batch_size
 
   environment = {
diff --git a/infrastructure/terraform/lambda/_template/variables.tf b/infrastructure/terraform/lambda/_template/variables.tf
index 0a3092ee..daaa0b7c 100644
--- a/infrastructure/terraform/lambda/_template/variables.tf
+++ b/infrastructure/terraform/lambda/_template/variables.tf
@@ -23,6 +23,12 @@ variable "maximum_concurrency" {
   description = "Maximum number of concurrent Lambda invocations from SQS (2-1000). null = no limit."
 }
 
+variable "reserved_concurrent_executions" {
+  type        = number
+  default     = -1
+  description = "Reserved concurrency for the Lambda function. -1 = unreserved. 1+ = hard limit across all triggers."
+}
+
 variable "batch_size" {
   type    = number
   default = 1
diff --git a/infrastructure/terraform/lambda/pashub_to_ara/main.tf b/infrastructure/terraform/lambda/pashub_to_ara/main.tf
index 0c652dc4..ae719a99 100644
--- a/infrastructure/terraform/lambda/pashub_to_ara/main.tf
+++ b/infrastructure/terraform/lambda/pashub_to_ara/main.tf
@@ -26,6 +26,8 @@ module "lambda" {
   # Optional: Set maximum_concurrency to limit concurrent SQS-triggered invocations (2-1000)
   maximum_concurrency = var.maximum_concurrency
 
+  reserved_concurrent_executions = var.reserved_concurrent_executions
+
   batch_size = var.batch_size
 
   environment = {
diff --git a/infrastructure/terraform/lambda/pashub_to_ara/variables.tf b/infrastructure/terraform/lambda/pashub_to_ara/variables.tf
index f16b41ac..e68a26b6 100644
--- a/infrastructure/terraform/lambda/pashub_to_ara/variables.tf
+++ b/infrastructure/terraform/lambda/pashub_to_ara/variables.tf
@@ -23,6 +23,12 @@ variable "maximum_concurrency" {
   description = "Maximum number of concurrent Lambda invocations from SQS (2-1000). null = no limit."
 }
 
+variable "reserved_concurrent_executions" {
+  type        = number
+  default     = 1
+  description = "Reserved concurrency. Defaults to 1 to prevent concurrent Playwright browser collisions."
+}
+
 variable "batch_size" {
   type    = number
   default = 1
diff --git a/infrastructure/terraform/modules/lambda_service/main.tf b/infrastructure/terraform/modules/lambda_service/main.tf
index 8a159db1..3250110b 100644
--- a/infrastructure/terraform/modules/lambda_service/main.tf
+++ b/infrastructure/terraform/modules/lambda_service/main.tf
@@ -9,6 +9,8 @@ resource "aws_lambda_function" "this" {
   memory_size = var.memory_size
   publish     = true
 
+  reserved_concurrent_executions = var.reserved_concurrent_executions
+
   environment {
     variables = var.environment
   }
diff --git a/infrastructure/terraform/modules/lambda_service/variables.tf b/infrastructure/terraform/modules/lambda_service/variables.tf
index 43def6ad..46241f30 100644
--- a/infrastructure/terraform/modules/lambda_service/variables.tf
+++ b/infrastructure/terraform/modules/lambda_service/variables.tf
@@ -16,3 +16,9 @@ variable "environment" {
   type    = map(string)
   default = {}
 }
+
+variable "reserved_concurrent_executions" {
+  type        = number
+  default     = -1
+  description = "Reserved concurrency for the Lambda function. -1 = unreserved (default). 0 = throttle all. 1+ = hard limit."
+}
diff --git a/infrastructure/terraform/modules/lambda_with_sqs/main.tf b/infrastructure/terraform/modules/lambda_with_sqs/main.tf
index 35626487..97f86793 100644
--- a/infrastructure/terraform/modules/lambda_with_sqs/main.tf
+++ b/infrastructure/terraform/modules/lambda_with_sqs/main.tf
@@ -31,7 +31,8 @@ module "lambda" {
   timeout     = var.timeout
   memory_size = var.memory_size
 
-  environment = var.environment
+  environment                     = var.environment
+  reserved_concurrent_executions  = var.reserved_concurrent_executions
 }
 
 ############################################
diff --git a/infrastructure/terraform/modules/lambda_with_sqs/variables.tf b/infrastructure/terraform/modules/lambda_with_sqs/variables.tf
index 7c2832d2..90585e92 100644
--- a/infrastructure/terraform/modules/lambda_with_sqs/variables.tf
+++ b/infrastructure/terraform/modules/lambda_with_sqs/variables.tf
@@ -40,3 +40,9 @@ variable "maximum_concurrency" {
   default     = null
   description = "Maximum number of concurrent Lambda invocations from SQS. null = no limit."
 }
+
+variable "reserved_concurrent_executions" {
+  type        = number
+  default     = -1
+  description = "Reserved concurrency for the Lambda function. -1 = unreserved. 1 = single-threaded."
+}