diff --git a/lib/towerops/proto/agent.pb.ex b/lib/towerops/proto/agent.pb.ex
new file mode 100644
index 00000000..195e666f
--- /dev/null
+++ b/lib/towerops/proto/agent.pb.ex
@@ -0,0 +1,173 @@
+defmodule Towerops.Agent.AgentConfig do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.AgentConfig",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :version, 1, type: :string
+  field :poll_interval_seconds, 2, type: :uint32, json_name: "pollIntervalSeconds"
+  field :equipment, 3, repeated: true, type: Towerops.Agent.Equipment
+end
+
+defmodule Towerops.Agent.Equipment do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.Equipment",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :id, 1, type: :string
+  field :name, 2, type: :string
+  field :ip_address, 3, type: :string, json_name: "ipAddress"
+  field :snmp, 4, type: Towerops.Agent.SnmpConfig
+  field :poll_interval_seconds, 5, type: :uint32, json_name: "pollIntervalSeconds"
+  field :sensors, 6, repeated: true, type: Towerops.Agent.Sensor
+  field :interfaces, 7, repeated: true, type: Towerops.Agent.Interface
+end
+
+defmodule Towerops.Agent.SnmpConfig do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.SnmpConfig",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :enabled, 1, type: :bool
+  field :version, 2, type: :string
+  field :community, 3, type: :string
+  field :port, 4, type: :uint32
+end
+
+defmodule Towerops.Agent.Sensor.MetadataEntry do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.Sensor.MetadataEntry",
+    map: true,
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :key, 1, type: :string
+  field :value, 2, type: :string
+end
+
+defmodule Towerops.Agent.Sensor do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.Sensor",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :id, 1, type: :string
+  field :type, 2, type: :string
+  field :oid, 3, type: :string
+  field :divisor, 4, type: :double
+  field :unit, 5, type: :string
+  field :metadata, 6, repeated: true, type: Towerops.Agent.Sensor.MetadataEntry, map: true
+end
+
+defmodule Towerops.Agent.Interface do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.Interface",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :id, 1, type: :string
+  field :if_index, 2, type: :uint32, json_name: "ifIndex"
+  field :if_name, 3, type: :string, json_name: "ifName"
+end
+
+defmodule Towerops.Agent.MetricBatch do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.MetricBatch",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :metrics, 1, repeated: true, type: Towerops.Agent.Metric
+end
+
+defmodule Towerops.Agent.Metric do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.Metric",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  oneof(:metric_type, 0)
+
+  field :sensor_reading, 1,
+    type: Towerops.Agent.SensorReading,
+    json_name: "sensorReading",
+    oneof: 0
+
+  field :interface_stat, 2,
+    type: Towerops.Agent.InterfaceStat,
+    json_name: "interfaceStat",
+    oneof: 0
+end
+
+defmodule Towerops.Agent.SensorReading do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.SensorReading",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :sensor_id, 1, type: :string, json_name: "sensorId"
+  field :value, 2, type: :double
+  field :status, 3, type: :string
+  field :timestamp, 4, type: :int64
+end
+
+defmodule Towerops.Agent.InterfaceStat do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.InterfaceStat",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :interface_id, 1, type: :string, json_name: "interfaceId"
+  field :if_in_octets, 2, type: :int64, json_name: "ifInOctets"
+  field :if_out_octets, 3, type: :int64, json_name: "ifOutOctets"
+  field :if_in_errors, 4, type: :int64, json_name: "ifInErrors"
+  field :if_out_errors, 5, type: :int64, json_name: "ifOutErrors"
+  field :if_in_discards, 6, type: :int64, json_name: "ifInDiscards"
+  field :if_out_discards, 7, type: :int64, json_name: "ifOutDiscards"
+  field :timestamp, 8, type: :int64
+end
+
+defmodule Towerops.Agent.HeartbeatMetadata do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.HeartbeatMetadata",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :version, 1, type: :string
+  field :hostname, 2, type: :string
+  field :uptime_seconds, 3, type: :uint64, json_name: "uptimeSeconds"
+end
+
+defmodule Towerops.Agent.HeartbeatResponse do
+  @moduledoc false
+
+  use Protobuf,
+    full_name: "towerops.agent.HeartbeatResponse",
+    protoc_gen_elixir_version: "0.16.0",
+    syntax: :proto3
+
+  field :status, 1, type: :string
+end
diff --git a/lib/towerops_web/controllers/api/agent_controller.ex b/lib/towerops_web/controllers/api/agent_controller.ex
index 78a1ec13..67274106 100644
--- a/lib/towerops_web/controllers/api/agent_controller.ex
+++ b/lib/towerops_web/controllers/api/agent_controller.ex
@@ -10,6 +10,7 @@ defmodule ToweropsWeb.Api.AgentController do
 
   use ToweropsWeb, :controller
 
+  alias Towerops.Agent.MetricBatch
   alias Towerops.Agents
   alias Towerops.Snmp
 
@@ -35,10 +36,24 @@ defmodule ToweropsWeb.Api.AgentController do
   POST /api/v1/agent/metrics
 
   Accepts a batch of metrics from the agent and processes them asynchronously.
+  Supports both JSON (legacy) and Protocol Buffers (efficient).
   """
-  def submit_metrics(conn, %{"metrics" => metrics}) when is_list(metrics) do
+  def submit_metrics(conn, params) do
     agent_token = conn.assigns.current_agent_token
 
+    metrics =
+      case get_req_header(conn, "content-type") do
+        ["application/x-protobuf" | _] ->
+          # Decode protobuf
+          {:ok, body, _conn} = Plug.Conn.read_body(conn)
+          batch = MetricBatch.decode(body)
+          convert_protobuf_metrics(batch.metrics)
+
+        _ ->
+          # JSON format (fallback)
+          Map.get(params, "metrics", [])
+      end
+
     Task.start(fn ->
       process_metrics(agent_token, metrics)
     end)
@@ -148,8 +163,47 @@ defmodule ToweropsWeb.Api.AgentController do
     end)
   end
 
+  defp convert_protobuf_metrics(metrics) do
+    metrics
+    |> Enum.map(fn metric ->
+      case metric.metric_type do
+        {:sensor_reading, sr} ->
+          %{
+            "type" => "sensor_reading",
+            "sensor_id" => sr.sensor_id,
+            "value" => sr.value,
+            "status" => sr.status,
+            "timestamp" => sr.timestamp
+          }
+
+        {:interface_stat, is} ->
+          %{
+            "type" => "interface_stat",
+            "interface_id" => is.interface_id,
+            "if_in_octets" => is.if_in_octets,
+            "if_out_octets" => is.if_out_octets,
+            "if_in_errors" => is.if_in_errors,
+            "if_out_errors" => is.if_out_errors,
+            "if_in_discards" => is.if_in_discards,
+            "if_out_discards" => is.if_out_discards,
+            "timestamp" => is.timestamp
+          }
+
+        _ ->
+          nil
+      end
+    end)
+    |> Enum.reject(&is_nil/1)
+  end
+
   defp parse_timestamp(nil), do: DateTime.truncate(DateTime.utc_now(), :second)
 
+  defp parse_timestamp(ts) when is_integer(ts) do
+    ts
+    |> DateTime.from_unix!(:second)
+    |> DateTime.truncate(:second)
+  end
+
   defp parse_timestamp(ts) when is_binary(ts) do
     case DateTime.from_iso8601(ts) do
       {:ok, dt, _} -> DateTime.truncate(dt, :second)
diff --git a/mix.exs b/mix.exs
index f173072c..54eaa8fa 100644
--- a/mix.exs
+++ b/mix.exs
@@ -59,6 +59,7 @@ defmodule Towerops.MixProject do
       {:ex_aws, "~> 2.5"},
       {:ex_aws_ses, "~> 2.4"},
       {:cbor, "~> 1.0"},
+      {:protobuf, "~> 0.12"},
       {:req, "~> 0.5"},
       {:snmpkit, "~> 1.3"},
       {:yaml_elixir, "~> 2.9"},
diff --git a/mix.lock b/mix.lock
index 61811fb0..49f1e416 100644
--- a/mix.lock
+++ b/mix.lock
@@ -48,6 +48,7 @@
   "plug": {:hex, :plug, "1.19.1", "09bac17ae7a001a68ae393658aa23c7e38782be5c5c00c80be82901262c394c0", [:mix], [{:mime, "~> 1.0 or ~> 2.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2 or ~> 2.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4.3 or ~> 1.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "560a0017a8f6d5d30146916862aaf9300b7280063651dd7e532b8be168511e62"},
   "plug_crypto": {:hex, :plug_crypto, "2.1.1", "19bda8184399cb24afa10be734f84a16ea0a2bc65054e23a62bb10f06bc89491", [:mix], [], "hexpm", "6470bce6ffe41c8bd497612ffde1a7e4af67f36a15eea5f921af71cf3e11247c"},
   "postgrex": {:hex, :postgrex, "0.21.1", "2c5cc830ec11e7a0067dd4d623c049b3ef807e9507a424985b8dcf921224cd88", [:mix], [{:db_connection, "~> 2.1", [hex: :db_connection, repo: "hexpm", optional: false]}, {:decimal, "~> 1.5 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:table, "~> 0.1.0", [hex: :table, repo: "hexpm", optional: true]}], "hexpm", "27d8d21c103c3cc68851b533ff99eef353e6a0ff98dc444ea751de43eb48bdac"},
+  "protobuf": {:hex, :protobuf, "0.16.0", "d1878725105d49162977cf3408ccc3eac4f3532e26e5a9e250f2c624175d10f6", [:mix], [{:jason, "~> 1.2", [hex: :jason, repo: "hexpm", optional: true]}], "hexpm", "f0d0d3edd8768130f24cc2cfc41320637d32c80110e80d13f160fa699102c828"},
   "req": {:hex, :req, "0.5.17", "0096ddd5b0ed6f576a03dde4b158a0c727215b15d2795e59e0916c6971066ede", [:mix], [{:brotli, "~> 0.3.1", [hex: :brotli, repo: "hexpm", optional: true]}, {:ezstd, "~> 1.0", [hex: :ezstd, repo: "hexpm", optional: true]}, {:finch, "~> 0.17", [hex: :finch, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}, {:mime, "~> 2.0.6 or ~> 2.1", [hex: :mime, repo: "hexpm", optional: false]}, {:nimble_csv, "~> 1.0", [hex: :nimble_csv, repo: "hexpm", optional: true]}, {:plug, "~> 1.0", [hex: :plug, repo: "hexpm", optional: true]}], "hexpm", "0b8bc6ffdfebbc07968e59d3ff96d52f2202d0536f10fef4dc11dc02a2a43e39"},
   "snmpkit": {:hex, :snmpkit, "1.3.19", "b09c38cea619a0a67d4fb0f3bfa3b9b749d42c400c2e7bd9446fef82f0d728a7", [:mix], [{:jason, "~> 1.4", [hex: :jason, repo: "hexpm", optional: false]}, {:telemetry, "~> 1.0", [hex: :telemetry, repo: "hexpm", optional: true]}, {:yaml_elixir, "~> 2.9", [hex: :yaml_elixir, repo: "hexpm", optional: true]}], "hexpm", "b05c1f3911204c4d781234187a6f1350c369fcffe2058a85b49735b1259eb973"},
   "sobelow": {:hex, :sobelow, "0.14.1", "2f81e8632f15574cba2402bcddff5497b413c01e6f094bc0ab94e83c2f74db81", [:mix], [{:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "8fac9a2bd90fdc4b15d6fca6e1608efb7f7c600fa75800813b794ee9364c87f2"},
diff --git a/priv/proto/agent.proto b/priv/proto/agent.proto
new file mode 100644
index 00000000..bacdbce5
--- /dev/null
+++ b/priv/proto/agent.proto
@@ -0,0 +1,83 @@
+syntax = "proto3";
+
+package towerops.agent;
+
+// Configuration received from the API
+message AgentConfig {
+  string version = 1;
+  uint32 poll_interval_seconds = 2;
+  repeated Equipment equipment = 3;
+}
+
+message Equipment {
+  string id = 1;
+  string name = 2;
+  string ip_address = 3;
+  SnmpConfig snmp = 4;
+  uint32 poll_interval_seconds = 5;
+  repeated Sensor sensors = 6;
+  repeated Interface interfaces = 7;
+}
+
+message SnmpConfig {
+  bool enabled = 1;
+  string version = 2;
+  string community = 3;
+  uint32 port = 4;
+}
+
+message Sensor {
+  string id = 1;
+  string type = 2;
+  string oid = 3;
+  double divisor = 4;
+  string unit = 5;
+  map<string, string> metadata = 6;
+}
+
+message Interface {
+  string id = 1;
+  uint32 if_index = 2;
+  string if_name = 3;
+}
+
+// Metrics submitted to the API
+message MetricBatch {
+  repeated Metric metrics = 1;
+}
+
+message Metric {
+  oneof metric_type {
+    SensorReading sensor_reading = 1;
+    InterfaceStat interface_stat = 2;
+  }
+}
+
+message SensorReading {
+  string sensor_id = 1;
+  double value = 2;
+  string status = 3;
+  int64 timestamp = 4; // Unix timestamp in seconds
+}
+
+message InterfaceStat {
+  string interface_id = 1;
+  int64 if_in_octets = 2;
+  int64 if_out_octets = 3;
+  int64 if_in_errors = 4;
+  int64 if_out_errors = 5;
+  int64 if_in_discards = 6;
+  int64 if_out_discards = 7;
+  int64 timestamp = 8; // Unix timestamp in seconds
+}
+
+// Heartbeat metadata
+message HeartbeatMetadata {
+  string version = 1;
+  string hostname = 2;
+  uint64 uptime_seconds = 3;
+}
+
+message HeartbeatResponse {
+  string status = 1;
+}
diff --git a/test/towerops_web/controllers/api/agent_controller_test.exs b/test/towerops_web/controllers/api/agent_controller_test.exs
index 86c90e0a..73814c7e 100644
--- a/test/towerops_web/controllers/api/agent_controller_test.exs
+++ b/test/towerops_web/controllers/api/agent_controller_test.exs
@@ -3,6 +3,10 @@ defmodule ToweropsWeb.Api.AgentControllerTest do
 
   import Towerops.AccountsFixtures
 
+  alias Towerops.Agent.InterfaceStat
+  alias Towerops.Agent.Metric
+  alias Towerops.Agent.MetricBatch
+  alias Towerops.Agent.SensorReading
   alias Towerops.Agents
   alias Towerops.Repo
   alias Towerops.Snmp.Device
@@ -164,6 +168,45 @@ defmodule ToweropsWeb.Api.AgentControllerTest do
 
       assert %{"status" => "accepted", "received" => 2} = json_response(conn, 200)
     end
+
+    test "accepts protobuf metrics", %{conn: conn, token: token} do
+      # Create protobuf metrics
+      sensor_reading = %SensorReading{
+        sensor_id: Ecto.UUID.generate(),
+        value: 45.5,
+        status: "ok",
+        timestamp: DateTime.to_unix(DateTime.utc_now())
+      }
+
+      interface_stat = %InterfaceStat{
+        interface_id: Ecto.UUID.generate(),
+        if_in_octets: 1_234_567,
+        if_out_octets: 9_876_543,
+        if_in_errors: 0,
+        if_out_errors: 0,
+        if_in_discards: 0,
+        if_out_discards: 0,
+        timestamp: DateTime.to_unix(DateTime.utc_now())
+      }
+
+      batch = %MetricBatch{
+        metrics: [
+          %Metric{metric_type: {:sensor_reading, sensor_reading}},
+          %Metric{metric_type: {:interface_stat, interface_stat}}
+        ]
+      }
+
+      # Encode to protobuf binary
+      encoded = MetricBatch.encode(batch)
+
+      conn =
+        conn
+        |> put_req_header("authorization", "Bearer #{token}")
+        |> put_req_header("content-type", "application/x-protobuf")
+        |> post(~p"/api/v1/agent/metrics", encoded)
+
+      assert %{"status" => "accepted", "received" => 2} = json_response(conn, 200)
+    end
   end
 
   describe "POST /api/v1/agent/heartbeat" do