diff --git a/src/food-market.public/src/components/SignupForm.tsx b/src/food-market.public/src/components/SignupForm.tsx
index c046465..160bcf9 100644
--- a/src/food-market.public/src/components/SignupForm.tsx
+++ b/src/food-market.public/src/components/SignupForm.tsx
@@ -1,4 +1,4 @@
-import { useState } from 'react'
+import { useState, useEffect } from 'react'
 import { validateEmail, validatePassword, validatePhone } from '@/lib/validation'
 import { PhoneInput } from '@/components/PhoneInput'
 import { PRICING, businessPrice, clamp, fmtKzt, type BusinessConfig } from '@/lib/pricing'
@@ -42,16 +42,44 @@ interface Props {
 
 type FieldErrors = Partial<Record<'email' | 'password' | 'orgName' | 'phone' | 'agree', string>>
 
+const DEFAULT_CONFIG: BusinessConfig = {
+  shops: PRICING.shops.min, cashes: PRICING.cashes.min,
+  warehouses: PRICING.warehouses.min, employees: PRICING.employees.min,
+}
+
 export default function SignupForm({ defaultPlan = 'start' }: Props) {
-  // Разбор ?plan= и конфигурации из URL — один раз при инициализации (клиент).
-  const [sel] = useState(() => readUrlSelection(defaultPlan))
-  const [config] = useState<BusinessConfig>(sel.config)
-  const hasConfig = sel.hasConfig
+  // Первый клиентский рендер ДОЛЖЕН совпасть с SSR-разметкой, иначе React кидает
+  // #418 (hydration mismatch). Поэтому стартуем из props/дефолтов, а ?plan= и
+  // конфигуратор читаем из URL уже в useEffect — после гидрации.
+  const initialPlan: PlanId = (VALID_PLANS as readonly string[]).includes(defaultPlan) ? (defaultPlan as PlanId) : 'start'
+  const [plan, setPlan] = useState<PlanId>(initialPlan)
+  const [config, setConfig] = useState<BusinessConfig>(DEFAULT_CONFIG)
+
+  useEffect(() => {
+    const sel = readUrlSelection(defaultPlan)
+    setPlan(sel.plan)
+    // Если план «Бизнес» без параметров конфигуратора — показываем дефолтную
+    // конфигурацию (1/1/1/5 = 10 000 ₸), а не пустой тариф.
+    setConfig(sel.hasConfig ? sel.config : DEFAULT_CONFIG)
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [])
+
+  // Клик по плитке тарифа — обновляем URL (?plan=…) без перезагрузки, чтобы
+  // ссылку можно было сохранить/поделиться.
+  const selectPlan = (id: PlanId) => {
+    setPlan(id)
+    if (typeof window !== 'undefined') {
+      const q = new URLSearchParams(window.location.search)
+      q.set('plan', id)
+      const qs = q.toString()
+      history.replaceState(null, '', `${window.location.pathname}${qs ? '?' + qs : ''}`)
+    }
+  }
+
   const [email, setEmail] = useState('')
   const [password, setPassword] = useState('')
   const [orgName, setOrgName] = useState('')
   const [phone, setPhone] = useState('')
-  const [plan, setPlan] = useState<string>(sel.plan)
   const businessTotal = businessPrice(config)
   const [agree, setAgree] = useState(false)
   const [busy, setBusy] = useState(false)
@@ -83,7 +111,7 @@ export default function SignupForm({ defaultPlan = 'start' }: Props) {
         // принимать ли — отдельно, см. отчёт site-fixes).
         body: JSON.stringify({
           email, password, organizationName: orgName, phone: phone || null, plan,
-          ...(plan === 'business' && hasConfig
+          ...(plan === 'business'
             ? { shops: config.shops, cashes: config.cashes, warehouses: config.warehouses, employees: config.employees }
             : {}),
         }),
@@ -195,18 +223,18 @@ export default function SignupForm({ defaultPlan = 'start' }: Props) {
         <div className="text-sm font-medium mb-2">Тариф</div>
         <div className="grid grid-cols-3 gap-2">
           {[
-            { id: 'start', name: 'Старт', price: fmtKzt(PRICING.startPrice) },
-            { id: 'business', name: 'Бизнес', price: hasConfig ? `${fmtKzt(businessTotal)}/мес` : 'от 10 000 ₸' },
+            { id: 'start', name: 'Старт', price: `${fmtKzt(PRICING.startPrice)}/мес` },
+            { id: 'business', name: 'Бизнес', price: `${fmtKzt(businessTotal)}/мес` },
             { id: 'network', name: 'Сеть', price: 'по запросу' },
           ].map((p) => (
             <label key={p.id} className={`p-2.5 rounded-md border cursor-pointer text-center text-sm ${plan === p.id ? 'border-brand bg-brand/5' : 'border-slate-200'}`}>
-              <input type="radio" name="plan" className="hidden" checked={plan === p.id} onChange={() => setPlan(p.id)} />
+              <input type="radio" name="plan" className="hidden" checked={plan === p.id} onChange={() => selectPlan(p.id as PlanId)} />
               <div className="font-semibold">{p.name}</div>
-              <div className="text-xs text-slate-500">{p.price}</div>
+              <div className="text-xs text-slate-500 whitespace-nowrap">{p.price}</div>
             </label>
           ))}
         </div>
-        {plan === 'business' && hasConfig && (
+        {plan === 'business' && (
           <div className="mt-3 rounded-md border border-brand/30 bg-brand/5 p-3 text-sm">
             <div className="flex items-baseline justify-between">
               <span className="font-medium">Ваша конфигурация «Бизнес»</span>