apps/api/src/routes/invoices.ts

@@ -42,6 +42,13 @@ const updateInvoiceSchema = z.object({
   taxCents: z.number().int().nonnegative().optional(),
   tipCents: z.number().int().nonnegative().optional(),
   notes: z.string().max(2000).nullable().optional(),
+  tipSplits: z.array(
+    z.object({
+      staffId: z.string().uuid().nullable(),
+      staffName: z.string().min(1).max(200),
+      sharePct: z.number().min(0).max(100),
+    })
+  ).optional(),
 });
 
 // List invoices
@@ -334,7 +341,30 @@ invoicesRouter.patch(
       }
     }
 
-    const update: Record<string, unknown> = { ...body, updatedAt: new Date() };
+    // Tip split validation when marking as paid with a tip
+    const effectiveTipCents = body.tipCents ?? current.tipCents;
+    if (body.status === "paid" && effectiveTipCents > 0) {
+      if (body.tipSplits !== undefined) {
+        if (body.tipSplits.length === 0) {
+          return c.json({ error: "Tip splits required when tip amount is greater than zero" }, 422);
+        }
+        const totalBps = body.tipSplits.reduce((sum, s) => sum + Math.round(s.sharePct * 100), 0);
+        if (totalBps !== 10000) {
+          return c.json({ error: "Split percentages must sum to 100" }, 422);
+        }
+      } else {
+        const existingSplits = await db
+          .select({ id: invoiceTipSplits.id })
+          .from(invoiceTipSplits)
+          .where(eq(invoiceTipSplits.invoiceId, id));
+        if (existingSplits.length === 0) {
+          return c.json({ error: "Tip splits required when tip amount is greater than zero" }, 422);
+        }
+      }
+    }
+
+    const { tipSplits: incomingTipSplits, ...bodyWithoutSplits } = body;
+    const update: Record<string, unknown> = { ...bodyWithoutSplits, updatedAt: new Date() };
 
     // Auto-set paidAt when marking as paid
     if (body.status === "paid" && !body.paidAt && !current.paidAt) {
@@ -348,11 +378,41 @@ invoicesRouter.patch(
       update.totalCents = current.subtotalCents + newTaxCents + newTipCents;
     }
 
-    const [updated] = await db
-      .update(invoices)
-      .set(update)
-      .where(eq(invoices.id, id))
-      .returning();
+    const [updated] = await db.transaction(async (tx) => {
+      const [upd] = await tx
+        .update(invoices)
+        .set(update)
+        .where(eq(invoices.id, id))
+        .returning();
+
+      // Atomically save tip splits when marking paid with provided splits
+      if (
+        body.status === "paid" &&
+        effectiveTipCents > 0 &&
+        incomingTipSplits !== undefined &&
+        incomingTipSplits.length > 0
+      ) {
+        await tx.delete(invoiceTipSplits).where(eq(invoiceTipSplits.invoiceId, id));
+
+        let remaining = effectiveTipCents;
+        const rows = incomingTipSplits.map((s, i) => {
+          const isLast = i === incomingTipSplits.length - 1;
+          const shareCents = isLast ? remaining : Math.round((s.sharePct / 100) * effectiveTipCents);
+          if (!isLast) remaining -= shareCents;
+          return {
+            invoiceId: id,
+            staffId: s.staffId,
+            staffName: s.staffName,
+            sharePct: s.sharePct.toFixed(2),
+            shareCents,
+          };
+        });
+
+        await tx.insert(invoiceTipSplits).values(rows);
+      }
+
+      return [upd];
+    });
 
     const lineItems = await db
       .select()

apps/web/src/pages/Clients.tsx

@@ -857,12 +857,56 @@ export function ClientsPage() {
 // ─── Shared UI ───────────────────────────────────────────────────────────────
 
 function Modal({ children, onClose }: { children: React.ReactNode; onClose: () => void }) {
+  const modalRef = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    const previouslyFocused = document.activeElement as HTMLElement;
+    const focusableSelectors = 'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])';
+    const focusableElements = modalRef.current?.querySelectorAll<HTMLElement>(focusableSelectors);
+    const firstFocusable = focusableElements?.[0];
+    firstFocusable?.focus();
+
+    function handleKeyDown(e: KeyboardEvent) {
+      if (e.key === "Escape") {
+        onClose();
+        return;
+      }
+      if (e.key !== "Tab") return;
+      if (!modalRef.current) return;
+      const focusables = modalRef.current.querySelectorAll<HTMLElement>(focusableSelectors);
+      const first = focusables[0];
+      const last = focusables[focusables.length - 1];
+      if (e.shiftKey) {
+        if (document.activeElement === first) {
+          e.preventDefault();
+          last?.focus();
+        }
+      } else {
+        if (document.activeElement === last) {
+          e.preventDefault();
+          first?.focus();
+        }
+      }
+    }
+
+    document.addEventListener("keydown", handleKeyDown);
+    return () => {
+      document.removeEventListener("keydown", handleKeyDown);
+      previouslyFocused?.focus();
+    };
+  }, [onClose]);
+
   return (
     <div
+      role="dialog"
+      aria-modal="true"
       style={{ position: "fixed", inset: 0, background: "rgba(0,0,0,0.45)", display: "flex", alignItems: "center", justifyContent: "center", zIndex: 100 }}
       onClick={(e) => { if (e.target === e.currentTarget) onClose(); }}
     >
-      <div style={{ background: "#fff", borderRadius: 8, padding: "1.5rem", maxWidth: 480, width: "calc(100% - 2rem)", maxHeight: "90vh", overflowY: "auto", boxShadow: "0 20px 60px rgba(0,0,0,0.3)" }}>
+      <div
+        ref={modalRef}
+        style={{ background: "#fff", borderRadius: 8, padding: "1.5rem", maxWidth: 480, width: "calc(100% - 2rem)", maxHeight: "90vh", overflowY: "auto", boxShadow: "0 20px 60px rgba(0,0,0,0.3)" }}
+      >
         {children}
       </div>
     </div>

apps/web/src/pages/Invoices.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useState } from "react";
+import { useEffect, useState, useRef } from "react";
 import type { Invoice, Client, Appointment, Service, Staff, InvoiceTipSplit } from "@groombook/types";
 
 // ─── Types ────────────────────────────────────────────────────────────────────
@@ -221,35 +221,31 @@ function InvoiceDetailModal({
       }
     }
     try {
+      const patchBody: {
+        status: string;
+        paymentMethod: string;
+        tipCents: number;
+        tipSplits?: Array<{ staffId: string | null; staffName: string; sharePct: number }>;
+      } = { status: "paid", paymentMethod, tipCents };
+
+      if (showSplits && tipCents > 0 && tipSplits.length > 0) {
+        patchBody.tipSplits = tipSplits.map((r) => ({
+          staffId: r.staffId,
+          staffName: r.staffName,
+          sharePct: r.pct,
+        }));
+      }
+
       const res = await fetch(`/api/invoices/${invoice.id}`, {
         method: "PATCH",
         headers: { "Content-Type": "application/json" },
-        body: JSON.stringify({ status: "paid", paymentMethod, tipCents }),
+        body: JSON.stringify(patchBody),
       });
       if (!res.ok) {
         const err = (await res.json()) as { error?: string };
         throw new Error(err.error ?? `HTTP ${res.status}`);
       }
 
-      // Save tip splits if applicable and tip > 0
-      if (showSplits && tipCents > 0 && tipSplits.length > 0) {
-        const totalPct = tipSplits.reduce((s, r) => s + r.pct, 0);
-        if (Math.abs(totalPct - 100) < 0.01) {
-          const splitsRes = await fetch(`/api/invoices/${invoice.id}/tip-splits`, {
-            method: "POST",
-            headers: { "Content-Type": "application/json" },
-            body: JSON.stringify({
-              splits: tipSplits.map((r) => ({
-                staffId: r.staffId,
-                staffName: r.staffName,
-                sharePct: r.pct,
-              })),
-            }),
-          });
-          if (!splitsRes.ok) console.warn("Tip split save failed (non-blocking)");
-        }
-      }
-
       onUpdated();
     } catch (e: unknown) {
       setError(e instanceof Error ? e.message : "Failed to update");
@@ -686,19 +682,63 @@ export function InvoicesPage() {
 // ─── Shared UI helpers ────────────────────────────────────────────────────────
 
 function Modal({ children, onClose }: { children: React.ReactNode; onClose: () => void }) {
+  const modalRef = useRef<HTMLDivElement>(null);
+
+  useEffect(() => {
+    const previouslyFocused = document.activeElement as HTMLElement;
+    const focusableSelectors = 'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])';
+    const focusableElements = modalRef.current?.querySelectorAll<HTMLElement>(focusableSelectors);
+    const firstFocusable = focusableElements?.[0];
+    firstFocusable?.focus();
+
+    function handleKeyDown(e: KeyboardEvent) {
+      if (e.key === "Escape") {
+        onClose();
+        return;
+      }
+      if (e.key !== "Tab") return;
+      if (!modalRef.current) return;
+      const focusables = modalRef.current.querySelectorAll<HTMLElement>(focusableSelectors);
+      const first = focusables[0];
+      const last = focusables[focusables.length - 1];
+      if (e.shiftKey) {
+        if (document.activeElement === first) {
+          e.preventDefault();
+          last?.focus();
+        }
+      } else {
+        if (document.activeElement === last) {
+          e.preventDefault();
+          first?.focus();
+        }
+      }
+    }
+
+    document.addEventListener("keydown", handleKeyDown);
+    return () => {
+      document.removeEventListener("keydown", handleKeyDown);
+      previouslyFocused?.focus();
+    };
+  }, [onClose]);
+
   return (
     <div
+      role="dialog"
+      aria-modal="true"
       style={{
         position: "fixed", inset: 0, background: "rgba(0,0,0,0.45)",
         display: "flex", alignItems: "center", justifyContent: "center", zIndex: 100,
       }}
       onClick={(e) => { if (e.target === e.currentTarget) onClose(); }}
     >
-      <div style={{
-        background: "#fff", borderRadius: 8, padding: "1.5rem",
-        maxWidth: 520, width: "calc(100% - 2rem)", maxHeight: "90vh", overflowY: "auto",
-        boxShadow: "0 20px 60px rgba(0,0,0,0.3)",
-      }}>
+      <div
+        ref={modalRef}
+        style={{
+          background: "#fff", borderRadius: 8, padding: "1.5rem",
+          maxWidth: 520, width: "calc(100% - 2rem)", maxHeight: "90vh", overflowY: "auto",
+          boxShadow: "0 20px 60px rgba(0,0,0,0.3)",
+        }}
+      >
         {children}
       </div>
     </div>

apps/web/src/portal/sections/BillingPayments.tsx

@@ -1,4 +1,4 @@
-import { useState, useEffect } from "react";
+import { useState, useEffect, useRef } from "react";
 import { loadStripe } from "@stripe/stripe-js";
 import { Elements, PaymentElement, useStripe, useElements } from "@stripe/react-stripe-js";
 import { CreditCard, DollarSign, Package, Zap } from "lucide-react";
@@ -356,6 +356,48 @@ function PaymentModal({ sessionId, pending, onClose, onSuccess }: PaymentModalPr
   const [isProcessing, setIsProcessing] = useState(false);
   const [isComplete, setIsComplete] = useState(false);
   const [error, setError] = useState<string | null>(null);
+  const completeModalRef = useRef<HTMLDivElement>(null);
+  const paymentModalRef = useRef<HTMLDivElement>(null);
+
+  // Focus trap + Escape-to-close for both inline modals
+  useEffect(() => {
+    const modalRef = isComplete ? completeModalRef.current : paymentModalRef.current;
+    if (!modalRef) return;
+
+    const previouslyFocused = document.activeElement as HTMLElement;
+    const focusableSelectors = 'button, [href], input, select, textarea, [tabindex]:not([tabindex="-1"])';
+    const focusableElements = modalRef.querySelectorAll<HTMLElement>(focusableSelectors);
+    const firstFocusable = focusableElements[0];
+    firstFocusable?.focus();
+
+    function handleKeyDown(e: KeyboardEvent) {
+      if (e.key === "Escape") {
+        onClose();
+        return;
+      }
+      if (e.key !== "Tab" || !modalRef) return;
+      const focusables = modalRef.querySelectorAll<HTMLElement>(focusableSelectors);
+      const first = focusables[0];
+      const last = focusables[focusables.length - 1];
+      if (e.shiftKey) {
+        if (document.activeElement === first) {
+          e.preventDefault();
+          last?.focus();
+        }
+      } else {
+        if (document.activeElement === last) {
+          e.preventDefault();
+          first?.focus();
+        }
+      }
+    }
+
+    document.addEventListener("keydown", handleKeyDown);
+    return () => {
+      document.removeEventListener("keydown", handleKeyDown);
+      previouslyFocused?.focus();
+    };
+  }, [isComplete, onClose]);
 
   const formatCents = (cents: number) =>
     new Intl.NumberFormat("en-US", { style: "currency", currency: "USD" }).format(cents / 100);
@@ -420,8 +462,8 @@ function PaymentModal({ sessionId, pending, onClose, onSuccess }: PaymentModalPr
 
   if (isComplete) {
     return (
-      <div className="fixed inset-0 bg-black/50 z-50 flex items-center justify-center p-4">
-        <div className="bg-white rounded-2xl shadow-xl max-w-md w-full p-8 text-center">
+      <div role="dialog" aria-modal="true" className="fixed inset-0 bg-black/50 z-50 flex items-center justify-center p-4">
+        <div ref={completeModalRef} className="bg-white rounded-2xl shadow-xl max-w-md w-full p-8 text-center">
           <div className="w-16 h-16 bg-green-100 rounded-full flex items-center justify-center mx-auto mb-4">
             <svg className="w-8 h-8 text-green-600" fill="none" stroke="currentColor" viewBox="0 0 24 24">
               <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M5 13l4 4L19 7" />
@@ -440,8 +482,8 @@ function PaymentModal({ sessionId, pending, onClose, onSuccess }: PaymentModalPr
   }
 
   return (
-    <div className="fixed inset-0 bg-black/50 z-50 flex items-center justify-center p-4">
-      <div className="bg-white rounded-2xl shadow-xl max-w-md w-full p-6">
+    <div role="dialog" aria-modal="true" className="fixed inset-0 bg-black/50 z-50 flex items-center justify-center p-4">
+      <div ref={paymentModalRef} className="bg-white rounded-2xl shadow-xl max-w-md w-full p-6">
         <div className="flex items-center justify-between mb-6">
           <h2 className="font-semibold text-stone-800 text-lg">Pay Outstanding Balance</h2>
           <button onClick={onClose} className="text-stone-400 hover:text-stone-600">