I’ve been asked by a few people for more details on the API Nest Labs uses for their thermostats, especially regarding setting data (and not just polling).

The API uses mostly JSON formatted data POSTed to their web servers.

Authentication

To authenticate, POST the username and password, encoded as form url-encoded:

POST https://home.nest.com/user/login HTTP/1.1
Host: home.nest.com
Proxy-Connection: keep-alive
Accept-Encoding: gzip, deflate
Content-Type: application/x-www-form-urlencoded; charset=utf-8
Accept-Language: en-us
Content-Length: {Length}
Accept: */*
Connection: keep-alive
User-Agent: Nest/3.0.1.15 (iOS) os=6.0 platform=iPad3,1

username={email}&password={password}

Adjust the email and password, and the content length to fit. You may need to remove the Accept-Encoding header value if your client cannot accept gzip or deflated responses.

The server responds with a healthy set of basic information (in JSON format):

{
    "is_superuser": false,
    "is_staff": false,
    "urls": {
        "transport_url": "https://{subdomain}.transport.nest.com:443",
        "rubyapi_url": "https://home.nest.com/",
        "weather_url": "http://www.wunderground.com/auto/nestlabs/geo/current/i?query=",
        "support_url": "https://nest.secure.force.com/support/webapp?"
    },
    "limits": {
        "thermostats_per_structure": 10,
        "structures": 2,
        "thermostats": 10
    },
    "access_token": "GIANT TOKEN STRING==",
    "userid": "1234",
    "expires_in": "Wed, 07-Oct-2012 12:08:00 GMT",
    "email": "user@example.com",
    "user": "user.1234"
}

There are a few things you’ll need from the response:

  • transport_url : this is the address for all of the later request that are made. I’d speculate it’s just a specific server in a server farm (likely with server affinity/session)
  • access_token : this is the key for all later requests and grants access to the API
  • userid/user : a unique user ID
  • expires_in : this is the timestamp for when the access token expires

I’m not sure why the “limits” are being sent back to the client.

You can obtain the service URLs at any time:

POST https://home.nest.com/user/service_urls HTTP/1.1
Host: home.nest.com
Authorization: Basic GIANT TOKEN STRING==
Accept-Encoding: gzip, deflate
Accept: */*
Content-Length: 0
Accept-Language: en-us
Connection: keep-alive
Proxy-Connection: keep-alive
User-Agent: Nest/3.0.1.15 (iOS) os=6.0 platform=iPad3,1

Just insert an Authorization header with the access_token value.

The response:

{ "urls": { "transport_url": "https://{subdomain}.transport.nest.com:443", "rubyapi_url": "https://home.nest.com/", "weather_url": "http://www.wunderground.com/auto/nestlabs/geo/current/i?query=", "support_url": "https://nest.secure.force.com/support/webapp?" }, "limits": { "thermostats_per_structure": 10, "structures": 2, "thermostats": 10 } }

Nest labs has a special URL at wunderground.com to access the weather.

One of the first requests you might want to send is to get a complete picture of the system:

GET https://{subdomain}.transport.nest.com:443/v2/mobile/#USER.ID# HTTP/1.1
Host: {subdomain}.transport.nest.com:443
Authorization: Basic GIANT TOKEN STRING==
Accept: */*
Accept-Encoding: gzip, deflate
Accept-Language: en-us
Connection: keep-alive
X-nl-protocol-version: 1
X-nl-user-id: #USERID#
Proxy-Connection: keep-alive
User-Agent: Nest/3.0.1.15 (iOS) os=6.0 platform=iPad3,1

You’ll make the request to the transport_url and make sure that the Host, Authorization, and X-nl-user-id header values are set appropriately. The Url now must include though:

  • version
  • mobile
  • and the full user id (like user.1234)

So, it will look something like: /v2/mobile/user.1234

It will respond with the mother-load of all JSON payloads. I’ve trimmed the response for my house as I have three thermostats. But the pattern repeats exactly, so it’s easy to extrapolate how the pattern works:

{ "metadata": { "SERIALNUM1": { "$version": -1262653277, "$timestamp": 1349697004000, "last_connection": 1349697004683, "last_ip": "LAST.IP.ADDRESS" }, "SERIALNUM2": { "$version": -1868790132, "$timestamp": 1349696678000, "last_connection": 1349696678701, "last_ip": "LAST.IP.ADDRESS" }, "SERIALNUM3": { "$version": -1581663504, "$timestamp": 1349696680000, "last_connection": 1349696680647, "last_ip": "LAST.IP.ADDRESS" } }, "track": { "SERIALNUM2": { "$version": 1065037529, "$timestamp": 1349696725390, "online": true, "last_connection": 1349696725390, "last_ip": "LAST.IP.ADDRESS" }, "SERIALNUM3": { "$version": 981680556, "$timestamp": 1349696726266, "online": true, "last_connection": 1349696726266, "last_ip": "LAST.IP.ADDRESS" }, "SERIALNUM1": { "$version": 1421919505, "$timestamp": 1349697004728, "online": true, "last_connection": 1349697004728, "last_ip": "LAST.IP.ADDRESS" } }, "user_settings": { "#USERID#": { "$version": 370836640, "$timestamp": 1337481029003, "email_verified": true, "tos_accepted_version": 1319500800000, "receive_marketing_emails": true, "receive_nest_emails": true, "receive_support_emails": true, "max_structures": 2, "max_thermostats": 10, "max_thermostats_per_structure": 10, "tos_minimum_version": 1319500800000, "tos_current_version": 1319500800000, "lang": "en_US" } }, "structure": { "#STRUCTURE-UUID#": { "$version": 1797929878, "$timestamp": 1349689810000, "location": "Mount Horeb, WI", "renovation_date": "2000", "country_code": "US", "away_timestamp": 1349302501, "away": false, "house_type": "family", "name": "Home", "postal_code": "#POSTALCODE#", "creation_time": 1324159145719, "num_thermostats": "3", "devices": ["device.SERIALNUM3", "device.SERIALNUM1", "device.SERIALNUM2"], "user": "user.#USERID#", "away_setter": 1 } }, "link": { "SERIALNUM3": { "$version": 2122853931, "$timestamp": 1327246591000, "structure": "structure.#STRUCTURE-UUID#" }, "SERIALNUM2": { "$version": -1703839727, "$timestamp": 1324159215000, "structure": "structure.#STRUCTURE-UUID#" }, "SERIALNUM1": { "$version": -459415854, "$timestamp": 1325967612000, "structure": "structure.#STRUCTURE-UUID#" } }, "device": { "SERIALNUM1": { "$version": -81037153, "$timestamp": 1349696605000, "heatpump_setback_active": false, "emer_heat_enable": false, "local_ip": "LOCAL.IP.ADDRESS", "switch_system_off": false, "away_temperature_high": 27.778, "temperature_lock_high_temp": 22.222, "cooling_source": "electric", "leaf_threshold_cool": 0.0, "fan_cooling_state": false, "note_codes": [], "heater_source": "gas", "compressor_lockout_leaf": -17.8, "has_x3_heat": false, "target_humidity_enabled": false, "heat_x3_source": "gas", "alt_heat_delivery": "forced-air", "fan_mode": "auto", "has_x2_heat": false, "rssi": 67.0, "emer_heat_delivery": "forced-air", "heatpump_savings": "off", "pin_y2_description": "none", "filter_reminder_enabled": false, "capability_level": 3.0, "schedule_learning_reset": false, "has_x2_cool": false, "hvac_pins": "W1,Y1,C,Rc,G", "ob_orientation": "O", "range_enable": true, "auto_away_enable": true, "dual_fuel_breakpoint_override": "none", "lower_safety_temp_enabled": true, "has_fan": true, "dehumidifier_state": false, "range_mode": false, "nlclient_state": "", "emer_heat_source": "electric", "heatpump_ready": false, "available_locales": "en_US,fr_CA,es_US", "current_version": "3.0.1", "learning_state": "slow", "pin_ob_description": "none", "pin_rh_description": "none", "has_alt_heat": false, "pin_y1_description": "cool", "humidifier_state": false, "backplate_serial_number": "#BACKPLATE-SERIALNUMBER1#", "has_x2_alt_heat": false, "heat_x3_delivery": "forced-air", "leaf_threshold_heat": 19.336, "has_emer_heat": false, "learning_mode": true, "leaf_learning": "ready", "has_aux_heat": false, "aux_heat_source": "electric", "backplate_bsl_info": "BSL", "alt_heat_x2_source": "gas", "pin_c_description": "power", "humidifier_type": "unknown", "pin_w2aux_description": "none", "country_code": "US", "target_humidity": 35.0, "heat_x2_delivery": "forced-air", "lower_safety_temp": 4.444, "cooling_x2_source": "electric", "equipment_type": "gas", "heat_pump_aux_threshold": 10.0, "alt_heat_x2_delivery": "forced-air", "heat_pump_comp_threshold": -31.5, "learning_days_completed_cool": 116, "backplate_bsl_version": "1.1", "current_schedule_mode": "HEAT", "hvac_wires": "Heat,Cool,Fan,Common Wire,Rc", "leaf": false, "type": "TBD", "pin_g_description": "fan", "switch_preconditioning_control": false, "click_sound": "on", "aux_heat_delivery": "forced-air", "away_temperature_low_enabled": true, "heat_pump_comp_threshold_enabled": false, "preconditioning_ready": true, "has_dehumidifier": false, "fan_cooling_enabled": true, "leaf_away_high": 28.88, "fan_cooling_readiness": "ready", "device_locale": "en_US", "temperature_scale": "F", "error_code": "", "preconditioning_active": false, "battery_level": 3.93, "away_temperature_high_enabled": true, "learning_days_completed_heat": 149, "pin_star_description": "none", "upper_safety_temp_enabled": false, "preconditioning_enabled": true, "current_humidity": 45, "dual_fuel_breakpoint": -1.0, "postal_code": "#POSTALCODE#", "backplate_mono_version": "4.0.5", "alt_heat_source": "gas", "aux_lockout_leaf": 10.0, "has_heat_pump": false, "heater_delivery": "forced-air", "auto_away_reset": false, "away_temperature_low": 14.444, "radiant_control_enabled": false, "temperature_lock": false, "upper_safety_temp": 35.0, "time_to_target_training": "ready", "dehumidifier_type": "unknown", "target_time_confidence": 1.0, "temperature_lock_low_temp": 20.0, "pin_w1_description": "heat", "forced_air": true, "temperature_lock_pin_hash": "", "leaf_type": 1, "backplate_mono_info": "TFE (BP_DVT) 4.0.5 (root@bamboo) 2012-09-18 18:18:23", "has_dual_fuel": false, "learning_time": 2113, "creation_time": 1325966794212, "has_humidifier": false, "learning_days_completed_range": 0, "leaf_schedule_delta": 1.11, "user_brightness": "auto", "leaf_away_low": 13.92, "pin_rc_description": "power", "serial_number": "SERIALNUM1", "mac_address": "18b43004f391", "heat_x2_source": "gas", "time_to_target": 0, "backplate_model": "Backplate-1.9", "model_version": "Diamond-1.10", "heat_pump_aux_threshold_enabled": true }, "SERIALNUM3": { "$version": 2134103145, "$timestamp": 1349695665000, /* same as previous */ "backplate_model": "Backplate-1.9", "model_version": "Diamond-1.10", "heat_pump_aux_threshold_enabled": true }, "SERIALNUM2": { "$version": -1340728480, "$timestamp": 1349692217000, /* same as previous */ "backplate_model": "Backplate-1.9", "model_version": "Diamond-1.10", "heat_pump_aux_threshold_enabled": true } }, "schedule": { "SERIALNUM3": { "$version": -1130522241, "$timestamp": 1349692663000, "days": { "3": { "3": { "time": 74700, "entry_type": "setpoint", "temp": 20.0, "type": "HEAT" }, "2": { "time": 23400, "entry_type": "setpoint", "temp": 14.444, "type": "HEAT" }, "1": { "time": 19800, "entry_type": "setpoint", "temp": 17.222, "type": "HEAT" }, "0": { "touched_by": 1, "time": 0, "touched_tzo": -18000, "entry_type": "continuation", "temp": 14.444, "type": "HEAT", "touched_at": 1349285499 }, "4": { "time": 78300, "entry_type": "setpoint", "temp": 14.444, "type": "HEAT" } }, "2": { "3": { "time": 74700, "entry_type": "setpoint", "temp": 20.0, "type": "HEAT" }, "2": { "time": 23400, "entry_type": "setpoint", "temp": 14.444, "type": "HEAT" }, "1": { "time": 19800, "entry_type": "setpoint", "temp": 17.222, "type": "HEAT" }, "0": { "touched_by": 1, "time": 0, "touched_tzo": -18000, "entry_type": "continuation", "temp": 14.444, "type": "HEAT", "touched_at": 1349285499 }, "4": { "time": 78300, "entry_type": "setpoint", "temp": 14.444, "type": "HEAT" } }, "1": { "3": { "time": 74700, "entry_type": "setpoint", "temp": 20.0, "type": "HEAT" }, "2": { "time": 23400, "entry_type": "setpoint", "temp": 14.444, "type": "HEAT" }, "1": { "time": 19800, "entry_type": "setpoint", "temp": 17.222, "type": "HEAT" }, "0": { "touched_by": 1, "time": 0, "touched_tzo": -18000, "entry_type": "continuation", "temp": 14.444, "type": "HEAT", "touched_at": 1349285499 }, "4": { "time": 78300, "entry_type": "setpoint", "temp": 14.444, "type": "HEAT" } }, "0": { "3": { "time": 74700, "entry_type": "setpoint", "temp": 20.0, "type": "HEAT" }, "2": { "time": 23400, "entry_type": "setpoint", "temp": 14.444, "type": "HEAT" }, "1": { "time": 19800, "entry_type": "setpoint", "temp": 17.222, "type": "HEAT" }, "0": { "touched_by": 1, "time": 0, "touched_tzo": -18000, "entry_type": "continuation", "temp": 14.444, "type": "HEAT", "touched_at": 1349285499 }, "4": { "time": 78300, "entry_type": "setpoint", "temp": 14.444, "type": "HEAT" } }, "6": { "3": { "time": 67500, "entry_type": "setpoint", "temp": 18.333, "type": "HEAT" }, "2": { "time": 28800, "entry_type": "setpoint", "temp": 14.444, "type": "HEAT" }, "1": { "time": 24300, "entry_type": "setpoint", "temp": 17.222, "type": "HEAT" }, "0": { "touched_by": 1, "time": 0, "touched_tzo": -18000, "entry_type": "continuation", "temp": 14.444, "type": "HEAT", "touched_at": 1349285499 }, "4": { "time": 75600, "entry_type": "setpoint", "temp": 14.444, "type": "HEAT" } }, "5": { "3": { "time": 67500, "entry_type": "setpoint", "temp": 18.333, "type": "HEAT" }, "2": { "time": 28800, "entry_type": "setpoint", "temp": 14.444, "type": "HEAT" }, "1": { "time": 24300, "entry_type": "setpoint", "temp": 17.222, "type": "HEAT" }, "0": { "touched_by": 1, "time": 0, "touched_tzo": -18000, "entry_type": "continuation", "temp": 14.444, "type": "HEAT", "touched_at": 1349285499 }, "4": { "time": 75600, "entry_type": "setpoint", "temp": 14.444, "type": "HEAT" } }, "4": { "3": { "time": 74700, "entry_type": "setpoint", "temp": 20.0, "type": "HEAT" }, "2": { "time": 23400, "entry_type": "setpoint", "temp": 14.444, "type": "HEAT" }, "1": { "time": 19800, "entry_type": "setpoint", "temp": 17.222, "type": "HEAT" }, "0": { "touched_by": 1, "time": 0, "touched_tzo": -18000, "entry_type": "continuation", "temp": 14.444, "type": "HEAT", "touched_at": 1349285499 }, "4": { "time": 78300, "entry_type": "setpoint", "temp": 14.444, "type": "HEAT" } } }, "schedule_mode": "HEAT", "name": "Basement Current Schedule", "ver": 2 }, "SERIALNUM2": { "$version": -462155699, "$timestamp": 1349674697000, "days": { /* SAME AS ABOVE */ } }, "schedule_mode": "HEAT", "name": "Second Floor Current Schedule", "ver": 2 }, "SERIALNUM1": { "$version": 2014520777, "$timestamp": 1349695806000, "days": { /* SAME AS ABOVE */ } }, "schedule_mode": "HEAT", "name": "First Floor Current Schedule", "ver": 2 } }, "shared": { "SERIALNUM3": { "$version": -493517056, "$timestamp": 1349696367000, "auto_away": 0, "auto_away_learning": "training", "hvac_heat_x3_state": false, "hvac_alt_heat_state": false, "compressor_lockout_enabled": false, "target_temperature_type": "heat", "hvac_heater_state": false, "hvac_emer_heat_state": false, "can_heat": true, "compressor_lockout_timeout": 0, "hvac_cool_x2_state": false, "target_temperature_high": 24.0, "hvac_aux_heater_state": false, "hvac_heat_x2_state": false, "target_temperature_low": 20.0, "target_temperature": 14.444, "hvac_ac_state": false, "hvac_fan_state": false, "target_change_pending": false, "name": "Basement", "current_temperature": 18.11, "hvac_alt_heat_x2_state": false, "can_cool": true }, "SERIALNUM1": { "$version": -1432433268, "$timestamp": 1349696363000 /* SAME AS ABOVE */ }, "SERIALNUM2": { "$version": 2060664119, "$timestamp": 1349696709000 /* SAME AS ABOVE */ } }, "user_alert_dialog": { "#USERID#": { "$version": -1852987123, "$timestamp": 1327246591000, "dialog_data": "", "dialog_id": "confirm-pairing" } }, "user": { "#USERID#": { "$version": 209478897, "$timestamp": 1324159145000, "name": "EMAILADDRESS", "structures": ["structure.#STRUCTURE-UUID#"] } } }

Setting a Temperature

Changing a thermostat’s current set point is easy.

You’ll need the Serial Number (shown as SERIALNUM1 in the JSON above) of the thermostat.

POST https://275be85a.transport.nest.com:443/v2/put/shared.01AA01AB4611009P HTTP/1.1
Host: 275be85a.transport.nest.com:443
Accept-Language: en-us
User-Agent: Nest/3.0.1.15 (iOS) os=6.0 platform=iPad3,1
X-nl-base-version: 2060664119
Accept: */*
Content-Type: application/json
X-nl-protocol-version: 1
X-nl-user-id: 7236
X-nl-session-id: ios-7236-371385438.528577
Connection: keep-alive
X-nl-merge-payload: true
Authorization: Basic GIANT TOKEN STRING==
Content-Length: 60
Proxy-Connection: keep-alive
Accept-Encoding: gzip, deflate

{"target_change_pending":true,"target_temperature":16.11111}

Set the temperature in Celsius.

There’s also a polling subscription that happens. It’s extremely chatty and from the amount of polling it does, you’d think that the UI was doing live graphing of micro-temperature changes.

Essentially, the polling sends a series of keys, with timestamps, representing the various types of data being requested.

It looks something like this:

{ "keys": [{ "key": "user.#USERID#", "version": 209478897, "timestamp": 1324159145000 }, { "key": "user_settings.#USERID#", "version": 370836640, "timestamp": 1337481029003 }, { "key": "user_alert_dialog.#USERID#", "version": -1852987123, "timestamp": 1327246591000 }, { 

It repeats for sections such as “shared”, “message”, “device”, “track”, and more. For my purposes, shared is the winner as it contains the current temperature.

 

Node API

I decided to write a new demonstration application and polish it up a bit, this time using Node.

I’m not going to document the API that I created here (not right now), but here’s a sample of how it can be used:

var username = process.argv[2];
var password = process.argv[3];

if (username && password) {
    username = trimQuotes(username);
    password = trimQuotes(password);
    nest.login(username, password, function (data) {
        if (!data) {
            console.log('Login failed.');
            process.exit(1);
            return;
        }
        console.log('Logged in.');
        nest.fetchStatus(function (data) {
            for (var deviceId in data.device) {
                if (data.device.hasOwnProperty(deviceId)) {
                    var device = data.shared[deviceId];

                    console.log(util.format("%s [%s], Current temperature = %d F target=%d",
                        device.name, deviceId,
                        nest.ctof(device.current_temperature),
                        nest.ctof(device.target_temperature)));
                }
            }
            subscribe();
        });
    });
}

function subscribe() {
    nest.subscribe(subscribeDone);
}

function subscribeDone(deviceId, data) {
    if (deviceId) {
        console.log('Device: ' + deviceId)
        console.log(JSON.stringify(data));
    }
    setTimeout(subscribe, 2000);
}

The example code runs forever. Smile

I’ve included two methods in the API, “get” and “post” which make it simple to call additional web services that I haven’t yet provided.

Find the code here: https://github.com/wiredprairie/unofficial_nodejs_nest.

Update: there’s a npm as well now (Dec 20, 2012)

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