diff --git a/frontend/i18n/locales/fr.json b/frontend/i18n/locales/fr.json
index e7c2342..ebce0f0 100644
--- a/frontend/i18n/locales/fr.json
+++ b/frontend/i18n/locales/fr.json
@@ -63,5 +63,10 @@
         "created": "Utilisateur créé avec succès.",
         "updated": "Utilisateur mis à jour avec succès.",
         "deleted": "Utilisateur supprimé avec succès."
+    },
+    "timeEntries": {
+        "created": "Temps enregistré",
+        "updated": "Temps modifié",
+        "deleted": "Temps supprimé"
     }
 }
diff --git a/frontend/services/dto/task.ts b/frontend/services/dto/task.ts
index 8b103b4..f3e47f2 100644
--- a/frontend/services/dto/task.ts
+++ b/frontend/services/dto/task.ts
@@ -4,6 +4,7 @@ import type { TaskPriority } from './task-priority'
 import type { TaskType } from './task-type'
 import type { TaskGroup } from './task-group'
 import type { UserData } from './user-data'
+import type { Project } from './project'
 
 export type Task = {
     id: number
@@ -15,6 +16,7 @@ export type Task = {
     priority: TaskPriority | null
     assignee: UserData | null
     group: TaskGroup | null
+    project: Project | null
     types: TaskType[]
 }
 
diff --git a/frontend/services/dto/time-entry.ts b/frontend/services/dto/time-entry.ts
new file mode 100644
index 0000000..9b3fb84
--- /dev/null
+++ b/frontend/services/dto/time-entry.ts
@@ -0,0 +1,28 @@
+import type { UserData } from './user-data'
+import type { Project } from './project'
+import type { Task } from './task'
+import type { TaskType } from './task-type'
+
+export type TimeEntry = {
+    id: number
+    '@id'?: string
+    title: string | null
+    description: string | null
+    startedAt: string
+    stoppedAt: string | null
+    user: UserData
+    project: Project | null
+    task: Task | null
+    types: TaskType[]
+}
+
+export type TimeEntryWrite = {
+    title?: string | null
+    description?: string | null
+    startedAt: string
+    stoppedAt?: string | null
+    user: string
+    project?: string | null
+    task?: string | null
+    types?: string[]
+}
diff --git a/frontend/services/time-entries.ts b/frontend/services/time-entries.ts
new file mode 100644
index 0000000..a37d766
--- /dev/null
+++ b/frontend/services/time-entries.ts
@@ -0,0 +1,53 @@
+import type { TimeEntry, TimeEntryWrite } from './dto/time-entry'
+import type { HydraCollection } from '~/utils/api'
+import { extractHydraMembers } from '~/utils/api'
+
+export function useTimeEntryService() {
+    const api = useApi()
+
+    async function getByDateRange(params: {
+        after: string
+        before: string
+        user?: number
+        types?: number[]
+    }): Promise<TimeEntry[]> {
+        const query: Record<string, unknown> = {
+            'startedAt[after]': params.after,
+            'startedAt[before]': params.before,
+        }
+        if (params.user) {
+            query.user = `/api/users/${params.user}`
+        }
+        const data = await api.get<HydraCollection<TimeEntry>>('/time_entries', query)
+        return extractHydraMembers(data)
+    }
+
+    async function getActive(): Promise<TimeEntry | null> {
+        try {
+            const result = await api.get<TimeEntry | null>('/time_entries/active', {}, { toast: false })
+            return result ?? null
+        } catch {
+            return null
+        }
+    }
+
+    async function create(payload: TimeEntryWrite): Promise<TimeEntry> {
+        return api.post<TimeEntry>('/time_entries', payload as Record<string, unknown>, {
+            toastSuccessKey: 'timeEntries.created',
+        })
+    }
+
+    async function update(id: number, payload: Partial<TimeEntryWrite>): Promise<TimeEntry> {
+        return api.patch<TimeEntry>(`/time_entries/${id}`, payload as Record<string, unknown>, {
+            toastSuccessKey: 'timeEntries.updated',
+        })
+    }
+
+    async function remove(id: number): Promise<void> {
+        await api.delete(`/time_entries/${id}`, {}, {
+            toastSuccessKey: 'timeEntries.deleted',
+        })
+    }
+
+    return { getByDateRange, getActive, create, update, remove }
+}
diff --git a/frontend/stores/timer.ts b/frontend/stores/timer.ts
new file mode 100644
index 0000000..463b4c0
--- /dev/null
+++ b/frontend/stores/timer.ts
@@ -0,0 +1,109 @@
+import { defineStore } from 'pinia'
+import type { TimeEntry } from '~/services/dto/time-entry'
+import type { Task } from '~/services/dto/task'
+import { useTimeEntryService } from '~/services/time-entries'
+
+export const useTimerStore = defineStore('timer', () => {
+    const activeEntry = ref<TimeEntry | null>(null)
+    const now = ref(Date.now())
+    let intervalId: ReturnType<typeof setInterval> | null = null
+
+    const isRunning = computed(() => activeEntry.value !== null)
+
+    const elapsed = computed(() => {
+        if (!activeEntry.value) return 0
+        const start = new Date(activeEntry.value.startedAt).getTime()
+        return Math.floor((now.value - start) / 1000)
+    })
+
+    const elapsedFormatted = computed(() => {
+        const total = elapsed.value
+        const h = Math.floor(total / 3600)
+        const m = Math.floor((total % 3600) / 60)
+        const s = total % 60
+        return [h, m, s].map((v) => String(v).padStart(2, '0')).join(':')
+    })
+
+    function startTicking() {
+        stopTicking()
+        now.value = Date.now()
+        intervalId = setInterval(() => {
+            now.value = Date.now()
+        }, 1000)
+    }
+
+    function stopTicking() {
+        if (intervalId) {
+            clearInterval(intervalId)
+            intervalId = null
+        }
+    }
+
+    async function fetchActive() {
+        const { getActive } = useTimeEntryService()
+        activeEntry.value = await getActive()
+        if (activeEntry.value) {
+            startTicking()
+        } else {
+            stopTicking()
+        }
+    }
+
+    async function start() {
+        const authStore = useAuthStore()
+        if (!authStore.user) return
+
+        if (isRunning.value) {
+            await stop()
+        }
+
+        const { create } = useTimeEntryService()
+        activeEntry.value = await create({
+            startedAt: new Date().toISOString(),
+            user: `/api/users/${authStore.user.id}`,
+        })
+        startTicking()
+    }
+
+    async function startFromTask(task: Task) {
+        const authStore = useAuthStore()
+        if (!authStore.user) return
+
+        if (isRunning.value) {
+            await stop()
+        }
+
+        const { create } = useTimeEntryService()
+        activeEntry.value = await create({
+            startedAt: new Date().toISOString(),
+            user: `/api/users/${authStore.user.id}`,
+            title: task.title,
+            project: task.project?.['@id'] ?? `/api/projects/${task.project?.id}`,
+            task: task['@id'] ?? `/api/tasks/${task.id}`,
+            types: task.types.map((t) => t['@id'] ?? `/api/task_types/${t.id}`),
+        })
+        startTicking()
+    }
+
+    async function stop() {
+        if (!activeEntry.value) return
+
+        const { update } = useTimeEntryService()
+        await update(activeEntry.value.id, {
+            stoppedAt: new Date().toISOString(),
+        })
+        activeEntry.value = null
+        stopTicking()
+    }
+
+    return {
+        activeEntry,
+        isRunning,
+        elapsed,
+        elapsedFormatted,
+        fetchActive,
+        start,
+        startFromTask,
+        stop,
+    }
+})