diff --git a/docs/API.md b/docs/API.md
index fbc6235..4357769 100644
--- a/docs/API.md
+++ b/docs/API.md
@@ -8,6 +8,12 @@ Default AP address:
 http://192.168.4.1
 ```
 
+Current API base path:
+
+```text
+/api/v1
+```
+
 All documented endpoints are local-first and must continue to work without internet access. Consumers should ignore unknown response fields for forward compatibility.
 
 Current firmware version:
@@ -20,34 +26,36 @@ Current firmware version:
 
 ```text
 GET  /
-GET  /status
-GET  /config
+GET  /api/v1/status
+GET  /api/v1/config
 
-POST /relay/set
+POST /api/v1/relay/set
 
-POST /config/device
-POST /config/relay
-POST /config/temp
-POST /config/bms
-POST /config/save
-POST /config/factory-reset
+POST /api/v1/config/device
+POST /api/v1/config/relay
+POST /api/v1/config/temp
+POST /api/v1/config/bms
+POST /api/v1/config/save
+POST /api/v1/config/factory-reset
 
-GET  /config/wifi
-POST /config/wifi
-POST /wifi/connect
-POST /wifi/clear
+GET  /api/v1/config/wifi
+POST /api/v1/config/wifi
+POST /api/v1/wifi/connect
+POST /api/v1/wifi/clear
 
-POST /temps/scan
-POST /temps/assign
-POST /temps/clear
+POST /api/v1/temps/scan
+POST /api/v1/temps/assign
+POST /api/v1/temps/clear
 
-POST /bms/setup/enter
-POST /bms/setup/exit
-POST /bms/scan
-POST /bms/select
+POST /api/v1/bms/setup/enter
+POST /api/v1/bms/setup/exit
+POST /api/v1/bms/scan
+POST /api/v1/bms/select
 ```
 
-Legacy relay routes remain available:
+Pre-versioned root routes remain registered as compatibility aliases for existing local clients. New clients should use `/api/v1`.
+
+Legacy GET relay routes remain available only as root compatibility aliases:
 
 ```text
 GET /relay/relay_1/on
@@ -61,15 +69,15 @@ GET /relay/relay_2/off
 The Waveshare ESP32-S3 dashboard MVP should use only:
 
 ```text
-GET  /status
-POST /relay/set
+GET  /api/v1/status
+POST /api/v1/relay/set
 ```
 
 The dashboard is a client only. It may cache last-known values for display, but the Cargo ESP32 remains the source of truth for relay state, BMS state, alarms, and configuration.
 
 ## Status
 
-### GET /status
+### GET /api/v1/status
 
 Returns complete controller status.
 
@@ -144,7 +152,7 @@ Fields:
 | `online` | Current sensor detection state |
 | `temperature_f` | Current Fahrenheit value, or `null` when offline |
 
-Config supports `temp_1` through `temp_8`. Current `/status` runtime output is limited to the configured count capped at four sensors.
+Config supports `temp_1` through `temp_8`. Current `/api/v1/status` runtime output is limited to the configured count capped at four sensors.
 
 ### relays
 
@@ -228,11 +236,11 @@ The AP remains enabled even when STA WiFi is configured or connected.
 
 ### config
 
-`/status.config` embeds the same core configuration model used by `GET /config`.
+`/api/v1/status.config` embeds the same core configuration model used by `GET /api/v1/config`.
 
 ## Configuration
 
-### GET /config
+### GET /api/v1/config
 
 Returns saved controller configuration.
 
@@ -264,9 +272,9 @@ Returns saved controller configuration.
 }
 ```
 
-Note: current `GET /config` omits the `weather` field, while `/status.config.temperature_sensors[]` includes it.
+Note: current `GET /api/v1/config` omits the `weather` field, while `/api/v1/status.config.temperature_sensors[]` includes it.
 
-### POST /config/device
+### POST /api/v1/config/device
 
 Updates the controller display name.
 
@@ -278,7 +286,7 @@ Updates the controller display name.
 
 Returns the updated config.
 
-### POST /config/relay
+### POST /api/v1/config/relay
 
 Updates relay configuration.
 
@@ -300,7 +308,7 @@ Fields:
 
 Returns the updated config.
 
-### POST /config/temp
+### POST /api/v1/config/temp
 
 Updates temperature sensor configuration.
 
@@ -326,7 +334,7 @@ Fields:
 
 Returns the updated config.
 
-### POST /config/bms
+### POST /api/v1/config/bms
 
 Updates BMS configuration.
 
@@ -348,13 +356,13 @@ random
 
 Returns the updated config.
 
-### POST /config/save
+### POST /api/v1/config/save
 
 Persists the current active configuration.
 
 Returns the current config.
 
-### POST /config/factory-reset
+### POST /api/v1/config/factory-reset
 
 Clears saved configuration and restores firmware defaults.
 
@@ -362,7 +370,7 @@ Returns the reset config.
 
 ## Relay Control
 
-### POST /relay/set
+### POST /api/v1/relay/set
 
 Preferred relay command endpoint.
 
@@ -407,7 +415,7 @@ Response:
 
 ## WiFi
 
-### GET /config/wifi
+### GET /api/v1/config/wifi
 
 Returns AP/STA WiFi configuration status. Passwords are not returned.
 
@@ -435,7 +443,7 @@ Returns AP/STA WiFi configuration status. Passwords are not returned.
 }
 ```
 
-### POST /config/wifi
+### POST /api/v1/config/wifi
 
 Preferred multi-network request:
 
@@ -473,13 +481,13 @@ Runtime behavior:
 - Lower priority numbers are tried first.
 - If STA disconnects, saved networks are retried by priority.
 
-### POST /wifi/connect
+### POST /api/v1/wifi/connect
 
 Attempts STA connection using saved networks by priority.
 
 Returns WiFi config status.
 
-### POST /wifi/clear
+### POST /api/v1/wifi/clear
 
 Clears saved STA WiFi networks.
 
@@ -487,7 +495,7 @@ Returns WiFi config status.
 
 ## Temperature Probe Setup
 
-### POST /temps/scan
+### POST /api/v1/temps/scan
 
 Scans the DS18B20 bus and returns unassigned probe addresses.
 
@@ -506,7 +514,7 @@ Scans the DS18B20 bus and returns unassigned probe addresses.
 
 Already-assigned probe addresses are hidden from scan results until cleared.
 
-### POST /temps/assign
+### POST /api/v1/temps/assign
 
 Assigns a scanned probe to a logical temperature slot.
 
@@ -530,7 +538,7 @@ By slot number:
 
 Returns the updated config.
 
-### POST /temps/clear
+### POST /api/v1/temps/clear
 
 Clears one or all temperature assignments.
 
@@ -560,7 +568,7 @@ Returns the updated config.
 
 These endpoints are for BMS discovery and selection. Do not change JBD/Xiaoxiang BLE behavior without explicit approval.
 
-### POST /bms/setup/enter
+### POST /api/v1/bms/setup/enter
 
 Enters BMS setup mode.
 
@@ -574,7 +582,7 @@ Response:
 }
 ```
 
-### POST /bms/setup/exit
+### POST /api/v1/bms/setup/exit
 
 Exits BMS setup mode.
 
@@ -588,7 +596,7 @@ Response:
 }
 ```
 
-### POST /bms/scan
+### POST /api/v1/bms/scan
 
 Scans for BLE devices.
 
@@ -610,7 +618,7 @@ Response:
 
 Some BMS devices advertise intermittently. Repeated scans may be needed.
 
-### POST /bms/select
+### POST /api/v1/bms/select
 
 Selects a BMS from the most recent scan result.
 
@@ -676,9 +684,9 @@ Some serial/UART errors use `message` instead of `error`; HTTP clients should re
 
 ## Compatibility
 
-Current stable route prefix is the root API path, for example `GET /status`.
+Current stable API prefix is `/api/v1`, for example `GET /api/v1/status`.
 
-Future versioning may move to `/api/v1`. Do not introduce versioned routes until consumers and docs are updated together.
+Pre-versioned root routes remain registered as local compatibility aliases. Do not add new root-only HTTP API routes.
 
 New fields may be added to existing JSON objects. Consumers should ignore unknown fields.
 
@@ -687,8 +695,8 @@ New fields may be added to existing JSON objects. Consumers should ignore unknow
 These routes are not part of the current registered HTTP API:
 
 ```text
-POST /bms/reconnect
-POST /system/restart
+POST /api/v1/bms/reconnect
+POST /api/v1/system/restart
 ```
 
 If added later, update this document and add contract tests.
diff --git a/docs/ARCHITECTURE.md b/docs/ARCHITECTURE.md
index 99bffa4..7b61e3e 100644
--- a/docs/ARCHITECTURE.md
+++ b/docs/ARCHITECTURE.md
@@ -93,11 +93,11 @@ HTTP is the primary integration contract for:
 
 Preferred direction:
 
-    GET  /status
-    GET  /config
-    POST /relay/set
+    GET  /api/v1/status
+    GET  /api/v1/config
+    POST /api/v1/relay/set
 
-Future versioning may move to /api/v1.
+Pre-versioned root routes remain registered as compatibility aliases for existing local clients.
 
 ## Generic IDs
 
diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index c0db0aa..d1dad89 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -21,7 +21,7 @@
 - WiFi priority and runtime reconnect behavior.
 - HTTP/UART/USB serial command parity documentation.
 - DS18B20 configurable temperature probe support.
-- Preferred relay command endpoint: `POST /relay/set`.
+- Preferred relay command endpoint: `POST /api/v1/relay/set`.
 
 ### Changed
 
diff --git a/docs/CONFIGURATION.md b/docs/CONFIGURATION.md
index 88f3148..92af0ce 100644
--- a/docs/CONFIGURATION.md
+++ b/docs/CONFIGURATION.md
@@ -38,7 +38,7 @@ Serial command:
 
 HTTP endpoint:
 
-    POST /config/device
+    POST /api/v1/config/device
 
 ## Relay Configuration
 
@@ -67,7 +67,7 @@ Serial commands:
 
 HTTP endpoint:
 
-    POST /config/relay
+    POST /api/v1/config/relay
 
 ## Temperature Sensor Configuration
 
@@ -102,7 +102,7 @@ Serial commands:
 
 HTTP endpoint:
 
-    POST /config/temp
+    POST /api/v1/config/temp
 
 ## BMS Configuration
 
@@ -127,7 +127,7 @@ Serial commands:
 
 HTTP endpoint:
 
-    POST /config/bms
+    POST /api/v1/config/bms
 
 ## BMS Setup Mode
 
@@ -157,7 +157,7 @@ Serial command:
 
 HTTP endpoint:
 
-    POST /config/factory-reset
+    POST /api/v1/config/factory-reset
 
 After factory reset:
 
diff --git a/docs/PARITY_MATRIX.md b/docs/PARITY_MATRIX.md
index d35c779..7084c70 100644
--- a/docs/PARITY_MATRIX.md
+++ b/docs/PARITY_MATRIX.md
@@ -12,14 +12,14 @@ Control surfaces:
 
 | Feature | USB Serial | UART JSON | HTTP API | Notes |
 |---|---:|---:|---:|---|
-| Status | Yes | Yes | Yes | `/status` equals `status_request` |
-| Config view | Yes | Yes | Yes | `/config` equals `config_request` |
-| Relay control | Yes | Yes | Yes | Preferred HTTP endpoint is `POST /relay/set` |
-| Device name config | Yes | Yes | Yes | `devicename`, `config_device`, `/config/device` |
-| Relay config | Yes | Yes | Yes | `relayname`, `config_relay`, `/config/relay` |
-| Temperature config | Yes | Yes | Yes | `tempname`, `config_temp`, `/config/temp` |
-| BMS config | Yes | Yes | Yes | `bmsname`/`bmsaddr`, `config_bms`, `/config/bms` |
-| Save config | Yes | Yes | Yes | `save`, `save_config`, `/config/save` |
+| Status | Yes | Yes | Yes | `/api/v1/status` equals `status_request` |
+| Config view | Yes | Yes | Yes | `/api/v1/config` equals `config_request` |
+| Relay control | Yes | Yes | Yes | Preferred HTTP endpoint is `POST /api/v1/relay/set` |
+| Device name config | Yes | Yes | Yes | `devicename`, `config_device`, `/api/v1/config/device` |
+| Relay config | Yes | Yes | Yes | `relayname`, `config_relay`, `/api/v1/config/relay` |
+| Temperature config | Yes | Yes | Yes | `tempname`, `config_temp`, `/api/v1/config/temp` |
+| BMS config | Yes | Yes | Yes | `bmsname`/`bmsaddr`, `config_bms`, `/api/v1/config/bms` |
+| Save config | Yes | Yes | Yes | `save`, `save_config`, `/api/v1/config/save` |
 | Factory reset | Yes | Yes | Yes | AP remains recovery path |
 | BMS setup enter | Yes | Yes | Yes | Setup pauses normal BMS reconnect behavior |
 | BMS setup exit | Yes | Yes | Yes | Returns to normal mode |
@@ -58,9 +58,9 @@ Legacy UART relay fields may still be accepted:
 
 Preferred HTTP relay endpoint:
 
-    POST /relay/set
+    POST /api/v1/relay/set
 
-Legacy HTTP relay routes may remain for compatibility:
+Legacy root HTTP relay routes remain for compatibility:
 
     GET /relay/relay_1/on
     GET /relay/relay_1/off
diff --git a/docs/dashboard-esp32s3.md b/docs/dashboard-esp32s3.md
index 148f39d..184499d 100644
--- a/docs/dashboard-esp32s3.md
+++ b/docs/dashboard-esp32s3.md
@@ -47,15 +47,15 @@ All grounds remain common.
 ## API endpoints consumed
 
 Minimum dashboard MVP:
-- GET /status
-- POST /relay/set
+- GET /api/v1/status
+- POST /api/v1/relay/set
 
 Potential later use:
-- GET /config
-- POST /config/save
-- POST /temps/scan
-- POST /temps/assign
-- POST /temps/clear
+- GET /api/v1/config
+- POST /api/v1/config/save
+- POST /api/v1/temps/scan
+- POST /api/v1/temps/assign
+- POST /api/v1/temps/clear
 
 ## MVP Display Goals
 
@@ -120,10 +120,10 @@ Then interactive:
 
 1. Dashboard boots.
 2. Connects to cargo ESP32 AP.
-3. Polls GET /status.
+3. Polls GET /api/v1/status.
 4. Shows disconnected state until valid JSON is received.
 5. Updates dashboard on a fixed interval.
-6. Relay buttons call POST /relay/set.
+6. Relay buttons call POST /api/v1/relay/set.
 
 ## Polling Guidance
 
diff --git a/firmware/esp32/overland-controller/overland-controller.ino b/firmware/esp32/overland-controller/overland-controller.ino
index c684ea2..dab79f9 100644
--- a/firmware/esp32/overland-controller/overland-controller.ino
+++ b/firmware/esp32/overland-controller/overland-controller.ino
@@ -209,7 +209,6 @@ input{width:100%;border:1px solid var(--line);border-radius:12px;padding:12px;ba
           </div>
           <div class="btnrow">
             <button onclick="setBmsEnabled(true)">Enable BMS</button>
-            <button onclick="reconnectBms()">Reconnect BMS</button>
           </div>
         </div>
       </section>
@@ -218,7 +217,6 @@ input{width:100%;border:1px solid var(--line);border-radius:12px;padding:12px;ba
         <div class="label">System Actions</div>
         <div class="sub">Use carefully. Factory reset clears install-specific configuration.</div>
         <div class="btnrow">
-          <button onclick="restartController()">Restart</button>
           <button class="off" onclick="factoryReset()">Factory Reset</button>
         </div>
       </section>
@@ -240,6 +238,8 @@ input{width:100%;border:1px solid var(--line);border-radius:12px;padding:12px;ba
 </div>
 
 <script>
+const API_BASE="/api/v1";
+function api(path){return API_BASE+path;}
 const $=id=>document.getElementById(id);
 function fmt(n,d=1){return typeof n==="number"?n.toFixed(d):"--"}
 function temp(v){return typeof v==="number"?fmt(v,1)+"°F":"Offline"}
@@ -323,12 +323,12 @@ function showTab(name){
   });
 }
 async function setBmsEnabled(enabled){
-  await fetch("/config/bms",{method:"POST",headers:{"Content-Type":"application/json"},body:JSON.stringify({enabled})});
-  await fetch("/config/save",{method:"POST"});
+  await fetch(api("/config/bms"),{method:"POST",headers:{"Content-Type":"application/json"},body:JSON.stringify({enabled})});
+  await fetch(api("/config/save"),{method:"POST"});
   await load();
 }
 async function relay(id,on){
-  await fetch("/relay/set",{method:"POST",headers:{"Content-Type":"application/json"},body:JSON.stringify({id,state:on})});
+  await fetch(api("/relay/set"),{method:"POST",headers:{"Content-Type":"application/json"},body:JSON.stringify({id,state:on})});
   await load();
 }
 function render(data){
@@ -411,13 +411,13 @@ async function saveDeviceConfig(){
   const name=$("deviceNameInput")?.value.trim();
   if(!name){ alert("Device name is required"); return; }
 
-  await fetch("/config/device",{
+  await fetch(api("/config/device"),{
     method:"POST",
     headers:{"Content-Type":"application/json"},
     body:JSON.stringify({device_name:name})
   });
 
-  await fetch("/config/save",{method:"POST"});
+  await fetch(api("/config/save"),{method:"POST"});
   await load();
   alert("Device name saved");
 }
@@ -432,7 +432,7 @@ async function saveBmsFullConfig(){
     return;
   }
 
-  await fetch("/config/bms",{
+  await fetch(api("/config/bms"),{
     method:"POST",
     headers:{"Content-Type":"application/json"},
     body:JSON.stringify({
@@ -443,22 +443,16 @@ async function saveBmsFullConfig(){
     })
   });
 
-  await fetch("/config/save",{method:"POST"});
-  await reconnectBms(false);
+  await fetch(api("/config/save"),{method:"POST"});
   await load();
   alert("BMS config saved");
 }
 
-async function reconnectBms(showAlert=true){
-  await fetch("/bms/reconnect",{method:"POST"});
-  if(showAlert) alert("BMS reconnect requested");
-}
-
 async function scanTemps(){
   const box=$("tempScanResults");
   if(box) box.innerHTML=`<div class="item"><span>Scanning...</span><strong class="muted">wait</strong></div>`;
 
-  const r=await fetch("/temps/scan",{method:"POST"});
+  const r=await fetch(api("/temps/scan"),{method:"POST"});
   const d=await r.json();
   const devices=d.devices||[];
 
@@ -487,13 +481,13 @@ async function scanTemps(){
 }
 
 async function assignTemp(id,index){
-  await fetch("/temps/assign",{
+  await fetch(api("/temps/assign"),{
     method:"POST",
     headers:{"Content-Type":"application/json"},
     body:JSON.stringify({id:id,index:index})
   });
 
-  await fetch("/config/save",{method:"POST"});
+  await fetch(api("/config/save"),{method:"POST"});
   await load();
   alert("Temp probe assigned to "+id);
 }
@@ -501,7 +495,7 @@ async function assignTemp(id,index){
 async function clearTempAssignment(id){
   if(!confirm("Clear probe assignment for "+id+"?")) return;
 
-  const r=await fetch("/temps/clear",{
+  const r=await fetch(api("/temps/clear"),{
     method:"POST",
     headers:{"Content-Type":"application/json"},
     body:JSON.stringify({id:id})
@@ -517,17 +511,11 @@ async function clearTempAssignment(id){
   alert("Temp probe assignment cleared for "+id);
 }
 
-async function restartController(){
-  if(!confirm("Restart the controller now?")) return;
-  await fetch("/system/restart",{method:"POST"});
-  alert("Restart requested");
-}
-
 async function factoryReset(){
   if(!confirm("Factory reset all controller configuration?")) return;
   if(!confirm("This clears WiFi/BMS/relay/temp config. Continue?")) return;
 
-  await fetch("/config/factory-reset",{method:"POST"});
+  await fetch(api("/config/factory-reset"),{method:"POST"});
   alert("Factory reset requested. Reconnect to the controller AP if needed.");
 }
 
@@ -574,7 +562,7 @@ function renderConfigControls(data){
 }
 
 async function saveRelayConfig(){
-  const r=await fetch("/status",{cache:"no-store"});
+  const r=await fetch(api("/status"),{cache:"no-store"});
   const data=await r.json();
   const relays=data.config?.relays||[];
 
@@ -582,7 +570,7 @@ async function saveRelayConfig(){
     const name=$("relayName"+i)?.value.trim();
     if(!name) continue;
 
-    await fetch("/config/relay",{
+    await fetch(api("/config/relay"),{
       method:"POST",
       headers:{"Content-Type":"application/json"},
       body:JSON.stringify({
@@ -593,13 +581,13 @@ async function saveRelayConfig(){
     });
   }
 
-  await fetch("/config/save",{method:"POST"});
+  await fetch(api("/config/save"),{method:"POST"});
   await load();
   alert("Relay names saved");
 }
 
 async function saveTempConfig(){
-  const r=await fetch("/status",{cache:"no-store"});
+  const r=await fetch(api("/status"),{cache:"no-store"});
   const data=await r.json();
   const temps=data.config?.temperature_sensors||[];
 
@@ -613,7 +601,7 @@ async function saveTempConfig(){
     const enabled=$("tempEnabled"+i)?.checked || false;
     const weather=$("tempWeather"+i)?.checked || false;
 
-    await fetch("/config/temp",{
+    await fetch(api("/config/temp"),{
       method:"POST",
       headers:{"Content-Type":"application/json"},
       body:JSON.stringify({
@@ -621,20 +609,19 @@ async function saveTempConfig(){
         name:name,
         address:temps[i].address||"",
         enabled:enabled,
-        weather:weather,
         weather:weather
       })
     });
   }
 
-  await fetch("/config/save",{method:"POST"});
+  await fetch(api("/config/save"),{method:"POST"});
   await load();
   alert("Temperature config saved");
 }
 
 async function loadWifiConfig(){
   try{
-    const r=await fetch("/config/wifi",{cache:"no-store"});
+    const r=await fetch(api("/config/wifi"),{cache:"no-store"});
     const d=await r.json();
     const nets=d.wifi?.networks||[];
     for(let i=0;i<3;i++){
@@ -652,17 +639,17 @@ async function saveWifi(){
     const priority=parseInt($("w"+i+"r").value||i,10);
     if(ssid) networks.push({ssid,password,priority});
   }
-  await fetch("/config/wifi",{method:"POST",headers:{"Content-Type":"application/json"},body:JSON.stringify({networks})});
+  await fetch(api("/config/wifi"),{method:"POST",headers:{"Content-Type":"application/json"},body:JSON.stringify({networks})});
   await loadWifiConfig();
   await load();
 }
 async function connectWifi(){
-  await fetch("/wifi/connect",{method:"POST"});
+  await fetch(api("/wifi/connect"),{method:"POST"});
   await load();
 }
 async function load(){
   try{
-    const r=await fetch("/status",{cache:"no-store"});
+    const r=await fetch(api("/status"),{cache:"no-store"});
     render(await r.json());
   }catch(e){
     $("conn").textContent="Offline";
@@ -678,6 +665,8 @@ setInterval(load,3000);
 )rawliteral";
 
 WebServer server(80);
+
+#define API_V1(path) "/api/v1" path
 HardwareSerial DashboardSerial(2);
 
 String uartLineBuffer;
@@ -2445,6 +2434,32 @@ void setup() {
         server.send_P(200, "text/html", INDEX_HTML);
     });
 
+    server.on(API_V1("/status"), handleStatus);
+    server.on(API_V1("/relay/set"), HTTP_POST, handleSetRelayPost);
+
+    server.on(API_V1("/config"), HTTP_GET, handleGetConfig);
+    server.on(API_V1("/config/wifi"), HTTP_GET, handleGetWifiConfig);
+    server.on(API_V1("/config/wifi"), HTTP_POST, handleUpdateWifiConfig);
+    server.on(API_V1("/wifi/connect"), HTTP_POST, handleWifiConnect);
+    server.on(API_V1("/wifi/clear"), HTTP_POST, handleWifiClear);
+
+    server.on(API_V1("/config/device"), HTTP_POST, handleUpdateDeviceConfig);
+    server.on(API_V1("/config/relay"), HTTP_POST, handleUpdateRelayConfig);
+    server.on(API_V1("/config/bms"), HTTP_POST, handleUpdateBmsConfig);
+    server.on(API_V1("/config/temp"), HTTP_POST, handleUpdateTempSensorConfig);
+    server.on(API_V1("/config/factory-reset"), HTTP_POST, handleFactoryResetConfig);
+    server.on(API_V1("/config/save"), HTTP_POST, handleSaveConfig);
+
+    server.on(API_V1("/temps/scan"), HTTP_POST, handleTempScan);
+    server.on(API_V1("/temps/assign"), HTTP_POST, handleTempAssign);
+    server.on(API_V1("/temps/clear"), HTTP_POST, handleTempClear);
+
+    server.on(API_V1("/bms/setup/enter"), HTTP_POST, handleEnterBmsSetup);
+    server.on(API_V1("/bms/setup/exit"), HTTP_POST, handleExitBmsSetup);
+    server.on(API_V1("/bms/scan"), HTTP_POST, handleBleScan);
+    server.on(API_V1("/bms/select"), HTTP_POST, handleSelectBms);
+
+    // Compatibility aliases for pre-versioned local clients.
     server.on("/status", handleStatus);
     server.on("/relay/set", HTTP_POST, handleSetRelayPost);
     server.on("/relay/relay_1/on", HTTP_GET, handleGenericRelayRoute);
diff --git a/pico-dashboard/comms/http_client.py b/pico-dashboard/comms/http_client.py
index 0cc45d0..4442fab 100644
--- a/pico-dashboard/comms/http_client.py
+++ b/pico-dashboard/comms/http_client.py
@@ -1,16 +1,17 @@
-import json
-
-
 class HttpClient:
     def __init__(self, requests_module, base_url="http://192.168.4.1"):
         self.requests = requests_module
         self.base_url = base_url.rstrip("/")
+        if not self.base_url.endswith("/api/v1"):
+            self.base_url = f"{self.base_url}/api/v1"
 
     def get_status(self):
         response = self.requests.get(f"{self.base_url}/status")
         return response.json()
 
     def set_relay(self, relay, enabled):
-        state = "on" if enabled else "off"
-        response = self.requests.get(f"{self.base_url}/relay/{relay}/{state}")
+        response = self.requests.post(
+            f"{self.base_url}/relay/set",
+            json={"id": relay, "state": enabled},
+        )
         return response.json()
diff --git a/pico-dashboard/state/app_state.py b/pico-dashboard/state/app_state.py
index e19a05d..1bf8d60 100644
--- a/pico-dashboard/state/app_state.py
+++ b/pico-dashboard/state/app_state.py
@@ -24,6 +24,8 @@ class AppState:
         }
 
         self.relays = {
+            "relay_1": False,
+            "relay_2": False,
             "starlink": False,
             "fridge": False,
         }
@@ -51,8 +53,8 @@ class AppState:
         self.network.update(message.get("network", {}))
 
     def update_from_relay_response(self, message):
-        relay = message.get("relay")
-        enabled = message.get("enabled")
+        relay = message.get("relay", message.get("id"))
+        enabled = message.get("enabled", message.get("state"))
 
         if relay in self.relays and enabled is not None:
             self.relays[relay] = bool(enabled)
diff --git a/tests/test_http_api_contract.py b/tests/test_http_api_contract.py
index 095074c..db9d45b 100644
--- a/tests/test_http_api_contract.py
+++ b/tests/test_http_api_contract.py
@@ -22,14 +22,41 @@ def assert_keys(payload, keys):
 
 
 def registered_routes():
-    pattern = re.compile(r'server\.on\("([^"]+)"(?:,\s*(HTTP_[A-Z]+))?')
-    return {(match.group(1), match.group(2) or "ANY") for match in pattern.finditer(firmware_source())}
+    source = firmware_source()
+    literal_pattern = re.compile(r'server\.on\("([^"]+)"(?:,\s*(HTTP_[A-Z]+))?')
+    macro_pattern = re.compile(r'server\.on\(API_V1\("([^"]+)"\)(?:,\s*(HTTP_[A-Z]+))?')
+
+    routes = {(match.group(1), match.group(2) or "ANY") for match in literal_pattern.finditer(source)}
+    routes.update({
+        (f"/api/v1{match.group(1)}", match.group(2) or "ANY")
+        for match in macro_pattern.finditer(source)
+    })
+    return routes
 
 
 def test_firmware_registers_current_http_contract_routes():
     routes = registered_routes()
 
     expected_routes = {
+        ("/api/v1/status", "ANY"),
+        ("/api/v1/config", "HTTP_GET"),
+        ("/api/v1/relay/set", "HTTP_POST"),
+        ("/api/v1/config/wifi", "HTTP_GET"),
+        ("/api/v1/config/wifi", "HTTP_POST"),
+        ("/api/v1/wifi/connect", "HTTP_POST"),
+        ("/api/v1/wifi/clear", "HTTP_POST"),
+        ("/api/v1/temps/scan", "HTTP_POST"),
+        ("/api/v1/temps/assign", "HTTP_POST"),
+        ("/api/v1/temps/clear", "HTTP_POST"),
+    }
+
+    assert expected_routes <= routes
+
+
+def test_firmware_keeps_root_compatibility_aliases():
+    routes = registered_routes()
+
+    compatibility_routes = {
         ("/status", "ANY"),
         ("/config", "HTTP_GET"),
         ("/relay/set", "HTTP_POST"),
@@ -42,7 +69,21 @@ def test_firmware_registers_current_http_contract_routes():
         ("/temps/clear", "HTTP_POST"),
     }
 
-    assert expected_routes <= routes
+    assert compatibility_routes <= routes
+
+
+def test_embedded_webui_uses_versioned_api_routes():
+    source = firmware_source()
+
+    assert 'const API_BASE="/api/v1";' in source
+    assert 'fetch(api("' in source
+    assert 'fetch("/status"' not in source
+    assert 'fetch("/config' not in source
+    assert 'fetch("/relay' not in source
+    assert 'fetch("/temps' not in source
+    assert 'fetch("/wifi' not in source
+    assert "/bms/reconnect" not in source
+    assert "/system/restart" not in source
 
 
 def test_status_fixture_matches_dashboard_contract_shape():
diff --git a/tests/test_pico_core.py b/tests/test_pico_core.py
index be00744..1d795b9 100644
--- a/tests/test_pico_core.py
+++ b/tests/test_pico_core.py
@@ -241,6 +241,7 @@ class FakeResponse:
 class FakeRequests:
     def __init__(self):
         self.urls = []
+        self.posts = []
         self.responses = []
 
     def get(self, url):
@@ -251,6 +252,15 @@ class FakeRequests:
 
         return FakeResponse({"ok": True})
 
+    def post(self, url, json=None):
+        self.urls.append(url)
+        self.posts.append({"url": url, "json": json})
+
+        if self.responses:
+            return FakeResponse(self.responses.pop(0))
+
+        return FakeResponse({"ok": True})
+
 
 def test_http_client_get_status():
     from comms.http_client import HttpClient
@@ -264,7 +274,7 @@ def test_http_client_get_status():
 
     payload = client.get_status()
 
-    assert fake_requests.urls == ["http://192.168.4.1/status"]
+    assert fake_requests.urls == ["http://192.168.4.1/api/v1/status"]
     assert payload["type"] == "status_response"
     assert payload["battery"]["soc"] == 82
 
@@ -275,9 +285,13 @@ def test_http_client_set_relay_on():
     fake_requests = FakeRequests()
     client = HttpClient(fake_requests)
 
-    payload = client.set_relay("starlink", True)
+    payload = client.set_relay("relay_1", True)
 
-    assert fake_requests.urls == ["http://192.168.4.1/relay/starlink/on"]
+    assert fake_requests.urls == ["http://192.168.4.1/api/v1/relay/set"]
+    assert fake_requests.posts == [{
+        "url": "http://192.168.4.1/api/v1/relay/set",
+        "json": {"id": "relay_1", "state": True},
+    }]
     assert payload == {"ok": True}
 
 
@@ -287,9 +301,13 @@ def test_http_client_set_relay_off():
     fake_requests = FakeRequests()
     client = HttpClient(fake_requests)
 
-    payload = client.set_relay("fridge", False)
+    payload = client.set_relay("relay_2", False)
 
-    assert fake_requests.urls == ["http://192.168.4.1/relay/fridge/off"]
+    assert fake_requests.urls == ["http://192.168.4.1/api/v1/relay/set"]
+    assert fake_requests.posts == [{
+        "url": "http://192.168.4.1/api/v1/relay/set",
+        "json": {"id": "relay_2", "state": False},
+    }]
     assert payload == {"ok": True}
 
 
@@ -317,7 +335,7 @@ def test_communication_service_http_fallback_status():
     assert response["type"] == "status_response"
     assert state.battery["soc"] == 66
     assert fake_uart.writes == []
-    assert fake_requests.urls == ["http://192.168.4.1/status"]
+    assert fake_requests.urls == ["http://192.168.4.1/api/v1/status"]
 
 
 def test_communication_service_http_fallback_relay():
@@ -330,8 +348,8 @@ def test_communication_service_http_fallback_relay():
     fake_requests.responses = [
         {
             "type": "relay_response",
-            "relay": "fridge",
-            "enabled": True,
+            "id": "relay_1",
+            "state": True,
             "ok": True,
         }
     ]
@@ -344,12 +362,16 @@ def test_communication_service_http_fallback_relay():
     )
 
     service.enable_http_fallback()
-    response = service.set_relay("fridge", True)
+    response = service.set_relay("relay_1", True)
 
     assert response["type"] == "relay_response"
-    assert state.relays["fridge"] is True
+    assert state.relays["relay_1"] is True
     assert fake_uart.writes == []
-    assert fake_requests.urls == ["http://192.168.4.1/relay/fridge/on"]
+    assert fake_requests.urls == ["http://192.168.4.1/api/v1/relay/set"]
+    assert fake_requests.posts == [{
+        "url": "http://192.168.4.1/api/v1/relay/set",
+        "json": {"id": "relay_1", "state": True},
+    }]
 
 
 def test_communication_service_marks_uart_connected_on_status():