diff --git a/app.js b/app.js
index 9e6b70e..17ce22a 100644
--- a/app.js
+++ b/app.js
@@ -7,6 +7,7 @@ const authRoutes = require('./src/routes/authRoutes');
 const profileRoutes = require('./src/routes/profileRoutes');
 const tripsRoutes = require('./src/routes/tripsRoutes');
 const driverLicenseRoutes = require('./src/routes/driverLicenseRoutes');
+const availabilityRoutes = require('./src/routes/availabilityRoutes');
 const { appendPostLog } = require('./src/utils/postLog');
 
 dotenv.config({ path: path.resolve(__dirname, '.env'), override: true });
@@ -107,6 +108,7 @@ app.use('/', authRoutes);
 app.use('/', profileRoutes);
 app.use('/', require('./src/routes/locationRoutes'));
 app.use('/api', require('./src/routes/stressRoutes')); // Stress Test Endpoint
+app.use('/api', availabilityRoutes);
 app.use('/api', tripsRoutes);
 app.use('/api', driverLicenseRoutes);
 
diff --git a/src/controllers/availabilityController.js b/src/controllers/availabilityController.js
new file mode 100644
index 0000000..ab40d48
--- /dev/null
+++ b/src/controllers/availabilityController.js
@@ -0,0 +1,102 @@
+const db = require('../config/db');
+
+const getCoordinatesFromBody = (body) => {
+    const lat = body?.latitud ?? body?.latitude;
+    const lng = body?.longitud ?? body?.longitude;
+
+    if (lat === undefined || lat === null || lng === undefined || lng === null) {
+        return null;
+    }
+
+    return { lat, lng };
+};
+
+const upsertOnlineAvailability = async (dni, lat, lng) => {
+    const [rows] = await db.query(
+        `SELECT id_usuario
+        FROM c_trazabilidad_online
+        WHERE id_usuario = ?
+        LIMIT 1`,
+        [dni]
+    );
+
+    if (rows.length > 0) {
+        await db.query(
+            `UPDATE c_trazabilidad_online
+            SET latitud = ?, longitud = ?, fecha = NOW()
+            WHERE id_usuario = ?`,
+            [String(lat), String(lng), dni]
+        );
+        return;
+    }
+
+    await db.query(
+        `INSERT INTO c_trazabilidad_online
+            (latitud, longitud, id_usuario, fecha)
+        VALUES (?, ?, ?, NOW())`,
+        [String(lat), String(lng), dni]
+    );
+};
+
+const getAvailability = async (req, res) => {
+    try {
+        const dni = String(req.user.dni);
+        const [rows] = await db.query(
+            `SELECT COUNT(*) AS total
+            FROM c_trazabilidad_online
+            WHERE id_usuario = ?`,
+            [dni]
+        );
+
+        return res.json({
+            success: true,
+            available: Number(rows[0]?.total || 0) > 0
+        });
+    } catch (error) {
+        console.error('Error getting availability:', error);
+        return res.status(500).json({ success: false, error: error.message });
+    }
+};
+
+const setAvailability = async (req, res) => {
+    try {
+        const coords = getCoordinatesFromBody(req.body);
+
+        if (!coords) {
+            return res.status(400).json({
+                success: false,
+                error: 'missing_coords',
+                message: 'latitud/longitud or latitude/longitude are required'
+            });
+        }
+
+        await upsertOnlineAvailability(String(req.user.dni), coords.lat, coords.lng);
+
+        return res.json({ success: true, available: true });
+    } catch (error) {
+        console.error('Error setting availability:', error);
+        return res.status(500).json({ success: false, error: error.message });
+    }
+};
+
+const deleteAvailability = async (req, res) => {
+    try {
+        await db.query(
+            `DELETE FROM c_trazabilidad_online
+            WHERE id_usuario = ?`,
+            [String(req.user.dni)]
+        );
+
+        return res.json({ success: true, available: false });
+    } catch (error) {
+        console.error('Error deleting availability:', error);
+        return res.status(500).json({ success: false, error: error.message });
+    }
+};
+
+module.exports = {
+    deleteAvailability,
+    getAvailability,
+    setAvailability,
+    upsertOnlineAvailability
+};
diff --git a/src/controllers/locationController.js b/src/controllers/locationController.js
index 3174ad8..c4652f9 100644
--- a/src/controllers/locationController.js
+++ b/src/controllers/locationController.js
@@ -1,5 +1,6 @@
 const db = require('../config/db');
 const agheeraPushClient = require('../services/agheeraPushClient');
+const { upsertOnlineAvailability } = require('./availabilityController');
 
 const AGHEERA_CLIENT_ID = 532;
 
@@ -73,6 +74,22 @@ const getTripIdFromLocation = (locationData) => {
     return null;
 };
 
+const isAvailabilityModeEnabled = (value) =>
+    value === true || value === 'true' || value === 1 || value === '1';
+
+const hasAvailabilityModeEnabled = (data, loc) => {
+    const candidates = [
+        data?.availability_mode,
+        data?.params?.availability_mode,
+        data?.extras?.availability_mode,
+        loc?.availability_mode,
+        loc?.params?.availability_mode,
+        loc?.extras?.availability_mode
+    ];
+
+    return candidates.some(isAvailabilityModeEnabled);
+};
+
 const getRawTimestampFromLocation = (locationData) => {
     const candidates = [
         locationData?.timestamp,
@@ -241,6 +258,7 @@ const saveLocation = async (req, res) => {
 
         const rowsToInsert = [];
         const locationsToPush = [];
+        const onlineAvailabilityUpdates = [];
 
         for (const loc of locations) {
             const coords = getCoordinatesFromLocation(loc);
@@ -274,6 +292,13 @@ const saveLocation = async (req, res) => {
                     tripId,
                     measurementTime: persistedTimestamp.value
                 });
+                if (dni && hasAvailabilityModeEnabled(data, loc)) {
+                    onlineAvailabilityUpdates.push({
+                        dni,
+                        lat: coords.lat,
+                        lng: coords.lng
+                    });
+                }
             }
         }
 
@@ -293,6 +318,11 @@ const saveLocation = async (req, res) => {
         );
 
         const agheeraResults = await pushLocationsToAgheera(locationsToPush);
+
+        for (const update of onlineAvailabilityUpdates) {
+            await upsertOnlineAvailability(update.dni, update.lat, update.lng);
+        }
+
         const responseBody = {
             success: true,
             count: rowsToInsert.length,
diff --git a/src/routes/availabilityRoutes.js b/src/routes/availabilityRoutes.js
new file mode 100644
index 0000000..42b0c80
--- /dev/null
+++ b/src/routes/availabilityRoutes.js
@@ -0,0 +1,11 @@
+const express = require('express');
+const availabilityController = require('../controllers/availabilityController');
+const authenticateDevice = require('../middleware/auth');
+
+const router = express.Router();
+
+router.get('/availability', authenticateDevice, availabilityController.getAvailability);
+router.post('/availability', authenticateDevice, availabilityController.setAvailability);
+router.delete('/availability', authenticateDevice, availabilityController.deleteAvailability);
+
+module.exports = router;
diff --git a/test/availability.integration.test.js b/test/availability.integration.test.js
new file mode 100644
index 0000000..d2ed0d0
--- /dev/null
+++ b/test/availability.integration.test.js
@@ -0,0 +1,360 @@
+const assert = require('node:assert/strict');
+const http = require('node:http');
+const test = require('node:test');
+const jwt = require('jsonwebtoken');
+
+const app = require('../app');
+const db = require('../src/config/db');
+
+const TEST_JWT_SECRET = 'test-jwt-secret';
+
+let originalQuery;
+let originalJwtSecret;
+
+const createToken = (payload = {}) =>
+    jwt.sign(
+        {
+            id: 1,
+            dni: '58045340X',
+            id_proveedor: 675,
+            ...payload
+        },
+        TEST_JWT_SECRET,
+        { expiresIn: '1h' }
+    );
+
+const withServer = async (callback) =>
+    new Promise((resolve, reject) => {
+        const server = app.listen(0, '127.0.0.1');
+
+        server.on('error', reject);
+        server.on('listening', async () => {
+            try {
+                const result = await callback(server);
+                server.close((closeError) => {
+                    if (closeError) {
+                        reject(closeError);
+                        return;
+                    }
+                    resolve(result);
+                });
+            } catch (error) {
+                server.close(() => reject(error));
+            }
+        });
+    });
+
+const requestJson = async ({ port, method, path, authorization, body }) =>
+    new Promise((resolve, reject) => {
+        const rawBody = body === undefined ? null : JSON.stringify(body);
+        const headers = {};
+
+        if (authorization) {
+            headers.authorization = authorization;
+        }
+
+        if (rawBody !== null) {
+            headers['Content-Type'] = 'application/json';
+            headers['Content-Length'] = Buffer.byteLength(rawBody);
+        }
+
+        const req = http.request(
+            {
+                hostname: '127.0.0.1',
+                port,
+                method,
+                path,
+                headers
+            },
+            (res) => {
+                let responseBody = '';
+
+                res.on('data', (chunk) => {
+                    responseBody += chunk;
+                });
+
+                res.on('end', () => {
+                    resolve({
+                        statusCode: res.statusCode,
+                        body: responseBody ? JSON.parse(responseBody) : null
+                    });
+                });
+            }
+        );
+
+        req.on('error', reject);
+        if (rawBody !== null) {
+            req.write(rawBody);
+        }
+        req.end();
+    });
+
+test.before(() => {
+    originalQuery = db.query;
+    originalJwtSecret = process.env.JWT_SECRET;
+});
+
+test.after(() => {
+    db.query = originalQuery;
+    process.env.JWT_SECRET = originalJwtSecret;
+});
+
+test.afterEach(() => {
+    db.query = originalQuery;
+});
+
+test('GET /api/availability devuelve available false si no hay fila', async () => {
+    process.env.JWT_SECRET = TEST_JWT_SECRET;
+
+    db.query = async (sql, params) => {
+        assert.match(sql, /COUNT\(\*\) AS total/);
+        assert.match(sql, /FROM c_trazabilidad_online/);
+        assert.deepEqual(params, ['58045340X']);
+        return [[{ total: 0 }]];
+    };
+
+    const response = await withServer((server) =>
+        requestJson({
+            port: server.address().port,
+            method: 'GET',
+            path: '/api/availability',
+            authorization: `Bearer ${createToken()}`
+        })
+    );
+
+    assert.equal(response.statusCode, 200);
+    assert.deepEqual(response.body, { success: true, available: false });
+});
+
+test('GET /api/availability devuelve available true si hay fila', async () => {
+    process.env.JWT_SECRET = TEST_JWT_SECRET;
+
+    db.query = async (sql, params) => {
+        assert.match(sql, /COUNT\(\*\) AS total/);
+        assert.match(sql, /FROM c_trazabilidad_online/);
+        assert.deepEqual(params, ['58045340X']);
+        return [[{ total: 1 }]];
+    };
+
+    const response = await withServer((server) =>
+        requestJson({
+            port: server.address().port,
+            method: 'GET',
+            path: '/api/availability',
+            authorization: `Bearer ${createToken()}`
+        })
+    );
+
+    assert.equal(response.statusCode, 200);
+    assert.deepEqual(response.body, { success: true, available: true });
+});
+
+test('POST /api/availability hace INSERT si no existe', async () => {
+    process.env.JWT_SECRET = TEST_JWT_SECRET;
+
+    let step = 0;
+    db.query = async (sql, params) => {
+        step += 1;
+
+        if (step === 1) {
+            assert.match(sql, /SELECT id_usuario/);
+            assert.match(sql, /FROM c_trazabilidad_online/);
+            assert.deepEqual(params, ['58045340X']);
+            return [[]];
+        }
+
+        assert.match(sql, /INSERT INTO c_trazabilidad_online/);
+        assert.deepEqual(params, ['40.416775', '-3.70379', '58045340X']);
+        return [{ affectedRows: 1 }];
+    };
+
+    const response = await withServer((server) =>
+        requestJson({
+            port: server.address().port,
+            method: 'POST',
+            path: '/api/availability',
+            authorization: `Bearer ${createToken()}`,
+            body: {
+                latitud: 40.416775,
+                longitud: -3.70379,
+                usuario: 'OTHER'
+            }
+        })
+    );
+
+    assert.equal(step, 2);
+    assert.equal(response.statusCode, 200);
+    assert.deepEqual(response.body, { success: true, available: true });
+});
+
+test('POST /api/availability hace UPDATE si existe', async () => {
+    process.env.JWT_SECRET = TEST_JWT_SECRET;
+
+    let step = 0;
+    db.query = async (sql, params) => {
+        step += 1;
+
+        if (step === 1) {
+            assert.match(sql, /SELECT id_usuario/);
+            assert.deepEqual(params, ['58045340X']);
+            return [[{ id_usuario: '58045340X' }]];
+        }
+
+        assert.match(sql, /UPDATE c_trazabilidad_online/);
+        assert.deepEqual(params, ['40.416775', '-3.70379', '58045340X']);
+        return [{ affectedRows: 1 }];
+    };
+
+    const response = await withServer((server) =>
+        requestJson({
+            port: server.address().port,
+            method: 'POST',
+            path: '/api/availability',
+            authorization: `Bearer ${createToken()}`,
+            body: {
+                latitude: 40.416775,
+                longitude: -3.70379
+            }
+        })
+    );
+
+    assert.equal(step, 2);
+    assert.equal(response.statusCode, 200);
+    assert.deepEqual(response.body, { success: true, available: true });
+});
+
+test('DELETE /api/availability borra la fila', async () => {
+    process.env.JWT_SECRET = TEST_JWT_SECRET;
+
+    db.query = async (sql, params) => {
+        assert.match(sql, /DELETE FROM c_trazabilidad_online/);
+        assert.deepEqual(params, ['58045340X']);
+        return [{ affectedRows: 1 }];
+    };
+
+    const response = await withServer((server) =>
+        requestJson({
+            port: server.address().port,
+            method: 'DELETE',
+            path: '/api/availability',
+            authorization: `Bearer ${createToken()}`
+        })
+    );
+
+    assert.equal(response.statusCode, 200);
+    assert.deepEqual(response.body, { success: true, available: false });
+});
+
+test('POST /api/locations con availability_mode true actualiza disponibilidad online', async () => {
+    process.env.JWT_SECRET = TEST_JWT_SECRET;
+
+    let step = 0;
+    db.query = async (sql, params) => {
+        step += 1;
+
+        if (step === 1) {
+            assert.match(sql, /INSERT INTO c_trazabilidad_transportista/);
+            assert.equal(params[0].length, 1);
+            assert.deepEqual(params[0][0].slice(0, 3), ['40.416775', '-3.70379', '58045340X']);
+            return [{ affectedRows: 1 }];
+        }
+
+        if (step === 2) {
+            assert.match(sql, /SELECT id_usuario/);
+            assert.match(sql, /FROM c_trazabilidad_online/);
+            assert.deepEqual(params, ['58045340X']);
+            return [[{ id_usuario: '58045340X' }]];
+        }
+
+        assert.match(sql, /UPDATE c_trazabilidad_online/);
+        assert.deepEqual(params, ['40.416775', '-3.70379', '58045340X']);
+        return [{ affectedRows: 1 }];
+    };
+
+    const response = await withServer((server) =>
+        requestJson({
+            port: server.address().port,
+            method: 'POST',
+            path: '/api/locations',
+            authorization: `Bearer ${createToken()}`,
+            body: {
+                location: [
+                    {
+                        coords: {
+                            latitude: 40.416775,
+                            longitude: -3.70379
+                        },
+                        params: {
+                            availability_mode: 'true'
+                        },
+                        timestamp: '2026-06-01T13:20:00Z'
+                    }
+                ]
+            }
+        })
+    );
+
+    assert.equal(step, 3);
+    assert.equal(response.statusCode, 200);
+    assert.deepEqual(response.body, {
+        success: true,
+        count: 1,
+        message: 'Locations saved'
+    });
+});
+
+test('POST /api/locations sin availability_mode no toca disponibilidad online', async () => {
+    process.env.JWT_SECRET = TEST_JWT_SECRET;
+
+    let calls = 0;
+    db.query = async (sql, params) => {
+        calls += 1;
+        assert.match(sql, /INSERT INTO c_trazabilidad_transportista/);
+        assert.deepEqual(params[0][0].slice(0, 3), ['40.416775', '-3.70379', '58045340X']);
+        return [{ affectedRows: 1 }];
+    };
+
+    const response = await withServer((server) =>
+        requestJson({
+            port: server.address().port,
+            method: 'POST',
+            path: '/api/locations',
+            authorization: `Bearer ${createToken()}`,
+            body: {
+                latitude: 40.416775,
+                longitude: -3.70379,
+                timestamp: '2026-06-01T13:20:00Z'
+            }
+        })
+    );
+
+    assert.equal(calls, 1);
+    assert.equal(response.statusCode, 200);
+    assert.deepEqual(response.body, {
+        success: true,
+        count: 1,
+        message: 'Locations saved'
+    });
+});
+
+test('todas las rutas nuevas requieren JWT valido', async () => {
+    process.env.JWT_SECRET = TEST_JWT_SECRET;
+
+    db.query = async () => {
+        throw new Error('db.query should not be called without token');
+    };
+
+    const responses = await withServer(async (server) => {
+        const port = server.address().port;
+        return Promise.all([
+            requestJson({ port, method: 'GET', path: '/api/availability' }),
+            requestJson({ port, method: 'POST', path: '/api/availability', body: { latitude: 1, longitude: 2 } }),
+            requestJson({ port, method: 'DELETE', path: '/api/availability' })
+        ]);
+    });
+
+    assert.deepEqual(
+        responses.map((response) => response.statusCode),
+        [401, 401, 401]
+    );
+});