diff --git a/src/routes/dashboard/billing/invoices-table.svelte b/src/routes/dashboard/billing/invoices-table.svelte
index 5cc5e84..e085bcc 100644
--- a/src/routes/dashboard/billing/invoices-table.svelte
+++ b/src/routes/dashboard/billing/invoices-table.svelte
@@ -1,6 +1,10 @@
 <script lang="ts">
-	/* eslint-disable @typescript-eslint/no-explicit-any */
+	import ExternalLinkIcon from '@lucide/svelte/icons/external-link';
+	import { resolve } from '$app/paths';
+	import { Badge, type BadgeVariant } from '$lib/components/ui/badge/index.js';
 	import * as Table from '$lib/components/ui/table/index.js';
+	import type { PageData } from './$types';
+
 	let {
 		data,
 		formatValue,
@@ -8,12 +12,19 @@
 		formatMoney,
 		relationLabel
 	}: {
-		data: any;
-		formatValue: any;
-		formatDate: any;
-		formatMoney: any;
-		relationLabel: any;
+		data: Pick<PageData, 'records'>;
+		formatValue: (value: unknown) => string;
+		formatDate: (value: unknown) => string;
+		formatMoney: (value: unknown) => string;
+		relationLabel: (value: unknown, optionsKey: 'clients') => string;
 	} = $props();
+
+	function statusVariant(status: string): BadgeVariant {
+		if (status === 'paid') return 'default';
+		if (status === 'void') return 'destructive';
+		if (status === 'draft') return 'outline';
+		return 'secondary';
+	}
 </script>
 
 {#if data.records.length > 0}
@@ -23,6 +34,7 @@
 				<Table.Row>
 					<Table.Head>Invoice #</Table.Head>
 					<Table.Head>Client</Table.Head>
+					<Table.Head>Status</Table.Head>
 					<Table.Head>Issued</Table.Head>
 					<Table.Head>Due</Table.Head>
 					<Table.Head>Total</Table.Head>
@@ -31,8 +43,19 @@
 			<Table.Body>
 				{#each data.records as record (record.id)}
 					<Table.Row>
-						<Table.Cell class="font-medium">{formatValue(record.invoiceNumber)}</Table.Cell>
+						<Table.Cell class="font-medium"
+							><a
+								class="inline-flex items-center gap-2 underline-offset-4 hover:text-primary hover:underline"
+								href={resolve('/dashboard/invoices/[id]', { id: record.id })}
+								>{formatValue(record.invoiceNumber)}<ExternalLinkIcon class="size-3.5" /></a
+							></Table.Cell
+						>
 						<Table.Cell class="">{relationLabel(record.clientId, 'clients')}</Table.Cell>
+						<Table.Cell
+							><Badge variant={statusVariant(record.status)} class="capitalize"
+								>{formatValue(record.status)}</Badge
+							></Table.Cell
+						>
 						<Table.Cell class="">{formatDate(record.issueDate)}</Table.Cell>
 						<Table.Cell class="">{formatDate(record.dueDate)}</Table.Cell>
 						<Table.Cell class="">{formatMoney(record.totalGbp)}</Table.Cell>
diff --git a/src/routes/dashboard/clients/[id]/invoices/invoices-table.svelte b/src/routes/dashboard/clients/[id]/invoices/invoices-table.svelte
index e1a83c2..7bdbaf6 100644
--- a/src/routes/dashboard/clients/[id]/invoices/invoices-table.svelte
+++ b/src/routes/dashboard/clients/[id]/invoices/invoices-table.svelte
@@ -1,17 +1,28 @@
 <script lang="ts">
-	/* eslint-disable @typescript-eslint/no-explicit-any */
+	import ExternalLinkIcon from '@lucide/svelte/icons/external-link';
+	import { resolve } from '$app/paths';
+	import { Badge, type BadgeVariant } from '$lib/components/ui/badge/index.js';
 	import * as Table from '$lib/components/ui/table/index.js';
+	import type { PageData } from './$types';
+
 	let {
 		data,
 		formatValue,
 		formatDate,
 		formatMoney
 	}: {
-		data: any;
-		formatValue: any;
-		formatDate: any;
-		formatMoney: any;
+		data: Pick<PageData, 'records'>;
+		formatValue: (value: unknown) => string;
+		formatDate: (value: unknown) => string;
+		formatMoney: (value: unknown) => string;
 	} = $props();
+
+	function statusVariant(status: string): BadgeVariant {
+		if (status === 'paid') return 'default';
+		if (status === 'void') return 'destructive';
+		if (status === 'draft') return 'outline';
+		return 'secondary';
+	}
 </script>
 
 {#if data.records.length > 0}
@@ -20,6 +31,7 @@
 			<Table.Header>
 				<Table.Row>
 					<Table.Head>Invoice #</Table.Head>
+					<Table.Head>Status</Table.Head>
 					<Table.Head>Issued</Table.Head>
 					<Table.Head>Due</Table.Head>
 					<Table.Head>Total</Table.Head>
@@ -28,7 +40,18 @@
 			<Table.Body>
 				{#each data.records as record (record.id)}
 					<Table.Row>
-						<Table.Cell class="font-medium">{formatValue(record.invoiceNumber)}</Table.Cell>
+						<Table.Cell class="font-medium"
+							><a
+								class="inline-flex items-center gap-2 underline-offset-4 hover:text-primary hover:underline"
+								href={resolve('/dashboard/invoices/[id]', { id: record.id })}
+								>{formatValue(record.invoiceNumber)}<ExternalLinkIcon class="size-3.5" /></a
+							></Table.Cell
+						>
+						<Table.Cell
+							><Badge variant={statusVariant(record.status)} class="capitalize"
+								>{formatValue(record.status)}</Badge
+							></Table.Cell
+						>
 						<Table.Cell class="">{formatDate(record.issueDate)}</Table.Cell>
 						<Table.Cell class="">{formatDate(record.dueDate)}</Table.Cell>
 						<Table.Cell class="">{formatMoney(record.totalGbp)}</Table.Cell>
diff --git a/src/routes/dashboard/invoices/[id]/+page.server.ts b/src/routes/dashboard/invoices/[id]/+page.server.ts
new file mode 100644
index 0000000..29d09c4
--- /dev/null
+++ b/src/routes/dashboard/invoices/[id]/+page.server.ts
@@ -0,0 +1,129 @@
+import { error, fail } from '@sveltejs/kit';
+import { and, asc, eq, isNull } from 'drizzle-orm';
+import { db } from '$lib/server/db';
+import { clients, invoiceLines, invoices } from '$lib/server/db/schema';
+import { loadOrganizationContext } from '$lib/server/organizations';
+import type { Actions, PageServerLoad } from './$types';
+
+type InvoiceStatus = 'draft' | 'sent' | 'paid' | 'void';
+type Transition = 'send' | 'markPaid' | 'void';
+
+const allowedTransitions: Record<Transition, InvoiceStatus[]> = {
+	send: ['draft'],
+	markPaid: ['sent'],
+	void: ['draft', 'sent']
+};
+
+const transitionStatus: Record<Transition, InvoiceStatus> = {
+	send: 'sent',
+	markPaid: 'paid',
+	void: 'void'
+};
+
+const transitionMessages: Record<Transition, string> = {
+	send: 'Only draft invoices can be marked as sent.',
+	markPaid: 'Only sent invoices can be marked as paid.',
+	void: 'Only draft or sent invoices can be voided.'
+};
+
+async function loadInvoice(organizationId: string, invoiceId: string) {
+	const [invoice] = await db
+		.select({
+			id: invoices.id,
+			organizationId: invoices.organizationId,
+			clientId: invoices.clientId,
+			clientName: clients.name,
+			invoiceNumber: invoices.invoiceNumber,
+			status: invoices.status,
+			sentAt: invoices.sentAt,
+			paidAt: invoices.paidAt,
+			voidedAt: invoices.voidedAt,
+			issueDate: invoices.issueDate,
+			dueDate: invoices.dueDate,
+			subtotalGbp: invoices.subtotalGbp,
+			taxGbp: invoices.taxGbp,
+			totalGbp: invoices.totalGbp,
+			notes: invoices.notes,
+			createdAt: invoices.createdAt,
+			updatedAt: invoices.updatedAt
+		})
+		.from(invoices)
+		.innerJoin(clients, eq(invoices.clientId, clients.id))
+		.where(
+			and(
+				eq(invoices.id, invoiceId),
+				eq(invoices.organizationId, organizationId),
+				isNull(invoices.archivedAt)
+			)
+		)
+		.limit(1);
+
+	if (!invoice) error(404, 'Invoice not found.');
+	return invoice;
+}
+
+async function transitionInvoice(
+	organizationId: string,
+	invoiceId: string,
+	transition: Transition
+) {
+	const invoice = await loadInvoice(organizationId, invoiceId);
+
+	if (!allowedTransitions[transition].includes(invoice.status)) {
+		return fail(400, { message: transitionMessages[transition] });
+	}
+
+	const now = new Date();
+	const nextStatus = transitionStatus[transition];
+
+	await db
+		.update(invoices)
+		.set({
+			status: nextStatus,
+			sentAt: transition === 'send' ? now : invoice.sentAt,
+			paidAt: transition === 'markPaid' ? now : invoice.paidAt,
+			voidedAt: transition === 'void' ? now : invoice.voidedAt,
+			updatedAt: now
+		})
+		.where(and(eq(invoices.id, invoiceId), eq(invoices.organizationId, organizationId)));
+
+	return { message: `Invoice ${invoice.invoiceNumber} marked as ${nextStatus}.` };
+}
+
+export const load: PageServerLoad = async ({ locals, params, parent }) => {
+	const { activeOrganizationId } = await loadOrganizationContext(locals);
+	const layoutData = await parent();
+	const invoice = await loadInvoice(activeOrganizationId, params.id);
+	const lines = await db
+		.select()
+		.from(invoiceLines)
+		.where(
+			and(
+				eq(invoiceLines.invoiceId, invoice.id),
+				eq(invoiceLines.organizationId, activeOrganizationId),
+				isNull(invoiceLines.archivedAt)
+			)
+		)
+		.orderBy(asc(invoiceLines.periodStart), asc(invoiceLines.description));
+
+	return {
+		invoice,
+		lines,
+		organization: layoutData.activeOrganization
+	};
+};
+
+export const actions: Actions = {
+	send: async ({ locals, params }) => {
+		const { activeOrganizationId } = await loadOrganizationContext(locals);
+		return transitionInvoice(activeOrganizationId, params.id, 'send');
+	},
+	markPaid: async ({ locals, params }) => {
+		const { activeOrganizationId } = await loadOrganizationContext(locals);
+		return transitionInvoice(activeOrganizationId, params.id, 'markPaid');
+	},
+	void: async ({ locals, params }) => {
+		const { activeOrganizationId } = await loadOrganizationContext(locals);
+		return transitionInvoice(activeOrganizationId, params.id, 'void');
+	}
+};
diff --git a/src/routes/dashboard/invoices/[id]/+page.svelte b/src/routes/dashboard/invoices/[id]/+page.svelte
new file mode 100644
index 0000000..b285117
--- /dev/null
+++ b/src/routes/dashboard/invoices/[id]/+page.svelte
@@ -0,0 +1,238 @@
+<script lang="ts">
+	import ArrowLeftIcon from '@lucide/svelte/icons/arrow-left';
+	import BanIcon from '@lucide/svelte/icons/ban';
+	import CheckCircle2Icon from '@lucide/svelte/icons/check-circle-2';
+	import PrinterIcon from '@lucide/svelte/icons/printer';
+	import SendIcon from '@lucide/svelte/icons/send';
+	import { resolve } from '$app/paths';
+	import { Badge, type BadgeVariant } from '$lib/components/ui/badge/index.js';
+	import { Button } from '$lib/components/ui/button/index.js';
+	import * as Table from '$lib/components/ui/table/index.js';
+	import type { ActionData, PageData } from './$types';
+
+	let { data, form }: { data: PageData; form: ActionData } = $props();
+
+	const canSend = $derived(data.invoice.status === 'draft');
+	const canMarkPaid = $derived(data.invoice.status === 'sent');
+	const canVoid = $derived(data.invoice.status === 'draft' || data.invoice.status === 'sent');
+
+	const lifecycleItems = $derived(
+		[
+			{ label: 'Sent', value: data.invoice.sentAt },
+			{ label: 'Paid', value: data.invoice.paidAt },
+			{ label: 'Voided', value: data.invoice.voidedAt }
+		].filter((item) => item.value)
+	);
+
+	function formatValue(value: unknown) {
+		if (value === null || value === undefined || value === '') return 'Not set';
+		return String(value);
+	}
+
+	function formatStatus(value: string) {
+		return value.replace('-', ' ');
+	}
+
+	function statusVariant(status: string): BadgeVariant {
+		if (status === 'paid') return 'default';
+		if (status === 'void') return 'destructive';
+		if (status === 'draft') return 'outline';
+		return 'secondary';
+	}
+
+	function formatMoney(value: unknown) {
+		const amount = typeof value === 'number' ? value : Number(value ?? 0);
+		return new Intl.NumberFormat('en-GB', { style: 'currency', currency: 'GBP' }).format(amount);
+	}
+
+	function formatDate(value: unknown, withTime = false) {
+		if (!value) return 'Not set';
+		const date = value instanceof Date ? value : new Date(String(value));
+		if (Number.isNaN(date.getTime())) return String(value);
+		return new Intl.DateTimeFormat('en-GB', {
+			day: '2-digit',
+			month: 'short',
+			year: 'numeric',
+			...(withTime ? { hour: '2-digit', minute: '2-digit' } : {})
+		}).format(date);
+	}
+
+	function printInvoice() {
+		window.print();
+	}
+</script>
+
+<svelte:head>
+	<title>{data.invoice.invoiceNumber} | Clearity</title>
+</svelte:head>
+
+<div class="flex flex-col gap-6">
+	<div class="no-print flex flex-col gap-3 sm:flex-row sm:items-center sm:justify-between">
+		<Button variant="ghost" href="/dashboard/billing" class="w-fit">
+			<ArrowLeftIcon data-icon="inline-start" />Billing
+		</Button>
+
+		<div class="flex flex-wrap gap-2">
+			<Button type="button" variant="outline" onclick={printInvoice}>
+				<PrinterIcon data-icon="inline-start" />Print
+			</Button>
+			<form method="POST" action="?/send">
+				<Button type="submit" disabled={!canSend}>
+					<SendIcon data-icon="inline-start" />Mark sent
+				</Button>
+			</form>
+			<form method="POST" action="?/markPaid">
+				<Button type="submit" variant="secondary" disabled={!canMarkPaid}>
+					<CheckCircle2Icon data-icon="inline-start" />Mark paid
+				</Button>
+			</form>
+			<form method="POST" action="?/void">
+				<Button type="submit" variant="destructive" disabled={!canVoid}>
+					<BanIcon data-icon="inline-start" />Void
+				</Button>
+			</form>
+		</div>
+	</div>
+
+	{#if form?.message}
+		<div class="no-print rounded-lg border border-border bg-muted/40 px-4 py-3 text-sm">
+			{form.message}
+		</div>
+	{/if}
+
+	<section class="grid gap-6 lg:grid-cols-[1fr_18rem]">
+		<div class="space-y-5">
+			<div class="flex flex-col gap-3 sm:flex-row sm:items-start sm:justify-between">
+				<div>
+					<p class="text-sm text-muted-foreground">Invoice</p>
+					<h1 class="text-2xl font-semibold tracking-tight">{data.invoice.invoiceNumber}</h1>
+				</div>
+				<Badge variant={statusVariant(data.invoice.status)} class="capitalize">
+					{formatStatus(data.invoice.status)}
+				</Badge>
+			</div>
+
+			<div class="grid gap-3 sm:grid-cols-3">
+				<div>
+					<p class="text-xs font-medium text-muted-foreground">Issued</p>
+					<p class="text-sm">{formatDate(data.invoice.issueDate)}</p>
+				</div>
+				<div>
+					<p class="text-xs font-medium text-muted-foreground">Due</p>
+					<p class="text-sm">{formatDate(data.invoice.dueDate)}</p>
+				</div>
+				<div>
+					<p class="text-xs font-medium text-muted-foreground">Updated</p>
+					<p class="text-sm">{formatDate(data.invoice.updatedAt, true)}</p>
+				</div>
+			</div>
+
+			{#if lifecycleItems.length > 0}
+				<div class="grid gap-3 sm:grid-cols-3">
+					{#each lifecycleItems as item (item.label)}
+						<div>
+							<p class="text-xs font-medium text-muted-foreground">{item.label}</p>
+							<p class="text-sm">{formatDate(item.value, true)}</p>
+						</div>
+					{/each}
+				</div>
+			{/if}
+		</div>
+
+		<div class="space-y-2 rounded-lg border border-border p-4">
+			<div class="flex justify-between gap-4 text-sm">
+				<span class="text-muted-foreground">Subtotal</span>
+				<span>{formatMoney(data.invoice.subtotalGbp)}</span>
+			</div>
+			<div class="flex justify-between gap-4 text-sm">
+				<span class="text-muted-foreground">Tax</span>
+				<span>{formatMoney(data.invoice.taxGbp)}</span>
+			</div>
+			<div class="flex justify-between gap-4 border-t border-border pt-3 text-base font-semibold">
+				<span>Total</span>
+				<span>{formatMoney(data.invoice.totalGbp)}</span>
+			</div>
+		</div>
+	</section>
+
+	<section class="grid gap-4 lg:grid-cols-2">
+		<div class="rounded-lg border border-border p-4">
+			<h2 class="text-sm font-semibold">Client</h2>
+			<a
+				class="mt-2 inline-flex text-sm underline-offset-4 hover:text-primary hover:underline"
+				href={resolve('/dashboard/clients/[id]/invoices', { id: data.invoice.clientId })}
+			>
+				{data.invoice.clientName}
+			</a>
+		</div>
+
+		<div class="rounded-lg border border-border p-4">
+			<h2 class="text-sm font-semibold">Payment</h2>
+			<div class="mt-2 grid gap-1 text-sm">
+				<p>{data.organization.name}</p>
+				<p>{formatValue(data.organization.bankName)}</p>
+				<p>{formatValue(data.organization.bankAccountName)}</p>
+				<p>
+					{formatValue(data.organization.bankSortCode)} / {formatValue(
+						data.organization.bankAccountNumber
+					)}
+				</p>
+				{#if data.organization.bankIban}
+					<p>IBAN {data.organization.bankIban}</p>
+				{/if}
+				{#if data.organization.bankSwift}
+					<p>SWIFT {data.organization.bankSwift}</p>
+				{/if}
+			</div>
+		</div>
+	</section>
+
+	<section class="overflow-hidden rounded-lg border border-border">
+		<Table.Root>
+			<Table.Header>
+				<Table.Row>
+					<Table.Head>Description</Table.Head>
+					<Table.Head>Period</Table.Head>
+					<Table.Head class="text-right">Qty</Table.Head>
+					<Table.Head class="text-right">Unit</Table.Head>
+					<Table.Head class="text-right">Total</Table.Head>
+				</Table.Row>
+			</Table.Header>
+			<Table.Body>
+				{#each data.lines as line (line.id)}
+					<Table.Row>
+						<Table.Cell class="font-medium">{line.description}</Table.Cell>
+						<Table.Cell>{formatDate(line.periodStart)} - {formatDate(line.periodEnd)}</Table.Cell>
+						<Table.Cell class="text-right">{line.quantity}</Table.Cell>
+						<Table.Cell class="text-right">{formatMoney(line.unitPriceGbp)}</Table.Cell>
+						<Table.Cell class="text-right">{formatMoney(line.totalGbp)}</Table.Cell>
+					</Table.Row>
+				{/each}
+			</Table.Body>
+		</Table.Root>
+	</section>
+
+	{#if data.invoice.notes}
+		<section class="rounded-lg border border-border p-4">
+			<h2 class="text-sm font-semibold">Notes</h2>
+			<p class="mt-2 whitespace-pre-wrap text-sm text-muted-foreground">{data.invoice.notes}</p>
+		</section>
+	{/if}
+</div>
+
+<style>
+	@media print {
+		.no-print {
+			display: none !important;
+		}
+
+		:global([data-slot='sidebar']),
+		:global([data-slot='breadcrumb']) {
+			display: none !important;
+		}
+
+		:global(body) {
+			background: white;
+		}
+	}
+</style>