diff --git a/apps/sim/app/api/chat/[identifier]/otp/route.ts b/apps/sim/app/api/chat/[identifier]/otp/route.ts
index 3cb30844d3..8ba425972d 100644
--- a/apps/sim/app/api/chat/[identifier]/otp/route.ts
+++ b/apps/sim/app/api/chat/[identifier]/otp/route.ts
@@ -6,7 +6,7 @@ import { z } from 'zod'
 import { renderOTPEmail } from '@/components/emails/render-email'
 import { sendEmail } from '@/lib/email/mailer'
 import { createLogger } from '@/lib/logs/console/logger'
-import { getRedisClient } from '@/lib/redis'
+import { getRedisClient, markMessageAsProcessed, releaseLock } from '@/lib/redis'
 import { generateRequestId } from '@/lib/utils'
 import { addCorsHeaders, setChatAuthCookie } from '@/app/api/chat/utils'
 import { createErrorResponse, createSuccessResponse } from '@/app/api/workflows/utils'
@@ -21,52 +21,83 @@ function generateOTP() {
 // We use 15 minutes (900 seconds) expiry for OTPs
 const OTP_EXPIRY = 15 * 60
 
-async function storeOTP(email: string, chatId: string, otp: string): Promise<boolean> {
+// Store OTP in Redis
+async function storeOTP(email: string, chatId: string, otp: string): Promise<void> {
   const key = `otp:${email}:${chatId}`
   const redis = getRedisClient()
 
-  if (!redis) {
-    logger.warn('Redis not available, OTP functionality requires Redis')
-    return false
-  }
-
-  try {
+  if (redis) {
+    // Use Redis if available
     await redis.set(key, otp, 'EX', OTP_EXPIRY)
-    return true
-  } catch (error) {
-    logger.error('Error storing OTP in Redis:', error)
-    return false
+  } else {
+    // Use the existing function as fallback to mark that an OTP exists
+    await markMessageAsProcessed(key, OTP_EXPIRY)
+
+    // For the fallback case, we need to handle storing the OTP value separately
+    // since markMessageAsProcessed only stores "1"
+    const valueKey = `${key}:value`
+    try {
+      // Access the in-memory cache directly - hacky but works for fallback
+      const inMemoryCache = (global as any).inMemoryCache
+      if (inMemoryCache) {
+        const fullKey = `processed:${valueKey}`
+        const expiry = OTP_EXPIRY ? Date.now() + OTP_EXPIRY * 1000 : null
+        inMemoryCache.set(fullKey, { value: otp, expiry })
+      }
+    } catch (error) {
+      logger.error('Error storing OTP in fallback cache:', error)
+    }
   }
 }
 
+// Get OTP from Redis
 async function getOTP(email: string, chatId: string): Promise<string | null> {
   const key = `otp:${email}:${chatId}`
   const redis = getRedisClient()
 
-  if (!redis) {
-    return null
+  if (redis) {
+    // Use Redis if available
+    return await redis.get(key)
   }
+  // Use the existing function as fallback - check if it exists
+  const exists = await new Promise((resolve) => {
+    try {
+      // Check the in-memory cache directly - hacky but works for fallback
+      const inMemoryCache = (global as any).inMemoryCache
+      const fullKey = `processed:${key}`
+      const cacheEntry = inMemoryCache?.get(fullKey)
+      resolve(!!cacheEntry)
+    } catch {
+      resolve(false)
+    }
+  })
+
+  if (!exists) return null
 
+  // Try to get the value key
+  const valueKey = `${key}:value`
   try {
-    return await redis.get(key)
-  } catch (error) {
-    logger.error('Error getting OTP from Redis:', error)
+    const inMemoryCache = (global as any).inMemoryCache
+    const fullKey = `processed:${valueKey}`
+    const cacheEntry = inMemoryCache?.get(fullKey)
+    return cacheEntry?.value || null
+  } catch {
     return null
   }
 }
 
+// Delete OTP from Redis
 async function deleteOTP(email: string, chatId: string): Promise<void> {
   const key = `otp:${email}:${chatId}`
   const redis = getRedisClient()
 
-  if (!redis) {
-    return
-  }
-
-  try {
+  if (redis) {
+    // Use Redis if available
     await redis.del(key)
-  } catch (error) {
-    logger.error('Error deleting OTP from Redis:', error)
+  } else {
+    // Use the existing function as fallback
+    await releaseLock(`processed:${key}`)
+    await releaseLock(`processed:${key}:value`)
   }
 }
 
@@ -146,17 +177,7 @@ export async function POST(
 
       const otp = generateOTP()
 
-      const stored = await storeOTP(email, deployment.id, otp)
-      if (!stored) {
-        logger.error(`[${requestId}] Failed to store OTP - Redis unavailable`)
-        return addCorsHeaders(
-          createErrorResponse(
-            'Email verification temporarily unavailable, please try again later',
-            503
-          ),
-          request
-        )
-      }
+      await storeOTP(email, deployment.id, otp)
 
       const emailHtml = await renderOTPEmail(
         otp,
diff --git a/apps/sim/lib/auth.ts b/apps/sim/lib/auth.ts
index f0486c6f1d..5dd170ad91 100644
--- a/apps/sim/lib/auth.ts
+++ b/apps/sim/lib/auth.ts
@@ -44,7 +44,6 @@ import { quickValidateEmail } from '@/lib/email/validation'
 import { env, isTruthy } from '@/lib/env'
 import { isBillingEnabled, isEmailVerificationEnabled } from '@/lib/environment'
 import { createLogger } from '@/lib/logs/console/logger'
-import { getRedisClient } from '@/lib/redis'
 import { SSO_TRUSTED_PROVIDERS } from './sso/consts'
 
 const logger = createLogger('Auth')
@@ -60,40 +59,6 @@ if (validStripeKey) {
   })
 }
 
-// Configure Redis secondary storage for session data (optional)
-const redis = getRedisClient()
-const redisSecondaryStorage = redis
-  ? {
-      get: async (key: string) => {
-        try {
-          const value = await redis.get(key)
-          return value
-        } catch (error) {
-          logger.error('Redis get error in secondaryStorage', { key, error })
-          return null
-        }
-      },
-      set: async (key: string, value: string, ttl?: number) => {
-        try {
-          if (ttl) {
-            await redis.set(key, value, 'EX', ttl)
-          } else {
-            await redis.set(key, value)
-          }
-        } catch (error) {
-          logger.error('Redis set error in secondaryStorage', { key, ttl, error })
-        }
-      },
-      delete: async (key: string) => {
-        try {
-          await redis.del(key)
-        } catch (error) {
-          logger.error('Redis delete error in secondaryStorage', { key, error })
-        }
-      },
-    }
-  : undefined
-
 export const auth = betterAuth({
   baseURL: getBaseURL(),
   trustedOrigins: [
@@ -104,8 +69,6 @@ export const auth = betterAuth({
     provider: 'pg',
     schema,
   }),
-  // Conditionally add secondaryStorage only if Redis is available
-  ...(redisSecondaryStorage ? { secondaryStorage: redisSecondaryStorage } : {}),
   session: {
     cookieCache: {
       enabled: true,
diff --git a/apps/sim/lib/redis.ts b/apps/sim/lib/redis.ts
index 8b7a8e029e..4944329a48 100644
--- a/apps/sim/lib/redis.ts
+++ b/apps/sim/lib/redis.ts
@@ -4,19 +4,25 @@ import { createLogger } from '@/lib/logs/console/logger'
 
 const logger = createLogger('Redis')
 
+// Only use Redis if explicitly configured
 const redisUrl = env.REDIS_URL
+
+// Global Redis client for connection pooling
 let globalRedisClient: Redis | null = null
 
-const MESSAGE_ID_PREFIX = 'processed:'
-const MESSAGE_ID_EXPIRY = 60 * 60 * 24 * 7
+// Fallback in-memory cache for when Redis is not available
+const inMemoryCache = new Map<string, { value: string; expiry: number | null }>()
+const MAX_CACHE_SIZE = 1000
 
 /**
  * Get a Redis client instance
  * Uses connection pooling to avoid creating a new connection for each request
  */
 export function getRedisClient(): Redis | null {
+  // For server-side only
   if (typeof window !== 'undefined') return null
 
+  // Return null immediately if no Redis URL is configured
   if (!redisUrl) {
     return null
   }
@@ -24,19 +30,25 @@ export function getRedisClient(): Redis | null {
   if (globalRedisClient) return globalRedisClient
 
   try {
+    // Create a new Redis client with optimized settings for serverless
     globalRedisClient = new Redis(redisUrl, {
+      // Keep alive is critical for serverless to reuse connections
       keepAlive: 1000,
+      // Faster connection timeout for serverless
       connectTimeout: 5000,
+      // Disable reconnection attempts in serverless
       maxRetriesPerRequest: 3,
+      // Retry strategy with exponential backoff
       retryStrategy: (times) => {
         if (times > 5) {
-          logger.warn('Redis connection failed after 5 attempts')
-          return null
+          logger.warn('Redis connection failed after 5 attempts, using fallback')
+          return null // Stop retrying
         }
-        return Math.min(times * 200, 2000)
+        return Math.min(times * 200, 2000) // Exponential backoff
       },
     })
 
+    // Handle connection events
     globalRedisClient.on('error', (err: any) => {
       logger.error('Redis connection error:', { err })
       if (err.code === 'ECONNREFUSED' || err.code === 'ETIMEDOUT') {
@@ -53,90 +65,144 @@ export function getRedisClient(): Redis | null {
   }
 }
 
+// Message ID cache functions
+const MESSAGE_ID_PREFIX = 'processed:' // Generic prefix
+const MESSAGE_ID_EXPIRY = 60 * 60 * 24 * 7 // 7 days in seconds
+
 /**
- * Check if a key exists in Redis
- * @param key The key to check
- * @returns True if the key exists, false otherwise
+ * Check if a key exists in Redis or fallback cache.
+ * @param key The key to check (e.g., messageId, lockKey).
+ * @returns True if the key exists and hasn't expired, false otherwise.
  */
 export async function hasProcessedMessage(key: string): Promise<boolean> {
-  const redis = getRedisClient()
-  if (!redis) {
-    return false
-  }
-
   try {
-    const fullKey = `${MESSAGE_ID_PREFIX}${key}`
-    const result = await redis.exists(fullKey)
-    return result === 1
+    const redis = getRedisClient()
+    const fullKey = `${MESSAGE_ID_PREFIX}${key}` // Use generic prefix
+
+    if (redis) {
+      // Use Redis if available
+      const result = await redis.exists(fullKey)
+      return result === 1
+    }
+    // Fallback to in-memory cache
+    const cacheEntry = inMemoryCache.get(fullKey)
+    if (!cacheEntry) return false
+
+    // Check if the entry has expired
+    if (cacheEntry.expiry && cacheEntry.expiry < Date.now()) {
+      inMemoryCache.delete(fullKey)
+      return false
+    }
+
+    return true
   } catch (error) {
     logger.error(`Error checking key ${key}:`, { error })
-    return false
+    // Fallback to in-memory cache on error
+    const fullKey = `${MESSAGE_ID_PREFIX}${key}`
+    const cacheEntry = inMemoryCache.get(fullKey)
+    return !!cacheEntry && (!cacheEntry.expiry || cacheEntry.expiry > Date.now())
   }
 }
 
 /**
- * Mark a key as processed in Redis
- * @param key The key to mark
- * @param expirySeconds Optional expiry time in seconds (defaults to 7 days)
+ * Mark a key as processed/present in Redis or fallback cache.
+ * @param key The key to mark (e.g., messageId, lockKey).
+ * @param expirySeconds Optional expiry time in seconds (defaults to 7 days).
  */
 export async function markMessageAsProcessed(
   key: string,
   expirySeconds: number = MESSAGE_ID_EXPIRY
 ): Promise<void> {
-  const redis = getRedisClient()
-  if (!redis) {
-    logger.warn(`Cannot mark message as processed - Redis unavailable: ${key}`)
-    return
-  }
-
   try {
-    const fullKey = `${MESSAGE_ID_PREFIX}${key}`
-    await redis.set(fullKey, '1', 'EX', expirySeconds)
+    const redis = getRedisClient()
+    const fullKey = `${MESSAGE_ID_PREFIX}${key}` // Use generic prefix
+
+    if (redis) {
+      // Use Redis if available - use pipelining for efficiency
+      await redis.set(fullKey, '1', 'EX', expirySeconds)
+    } else {
+      // Fallback to in-memory cache
+      const expiry = expirySeconds ? Date.now() + expirySeconds * 1000 : null
+      inMemoryCache.set(fullKey, { value: '1', expiry })
+
+      // Clean up old message IDs if cache gets too large
+      if (inMemoryCache.size > MAX_CACHE_SIZE) {
+        const now = Date.now()
+
+        // First try to remove expired entries
+        for (const [cacheKey, entry] of inMemoryCache.entries()) {
+          if (entry.expiry && entry.expiry < now) {
+            inMemoryCache.delete(cacheKey)
+          }
+        }
+
+        // If still too large, remove oldest entries (FIFO based on insertion order)
+        if (inMemoryCache.size > MAX_CACHE_SIZE) {
+          const keysToDelete = Array.from(inMemoryCache.keys()).slice(
+            0,
+            inMemoryCache.size - MAX_CACHE_SIZE
+          )
+
+          for (const keyToDelete of keysToDelete) {
+            inMemoryCache.delete(keyToDelete)
+          }
+        }
+      }
+    }
   } catch (error) {
     logger.error(`Error marking key ${key} as processed:`, { error })
+    // Fallback to in-memory cache on error
+    const fullKey = `${MESSAGE_ID_PREFIX}${key}`
+    const expiry = expirySeconds ? Date.now() + expirySeconds * 1000 : null
+    inMemoryCache.set(fullKey, { value: '1', expiry })
   }
 }
 
 /**
- * Attempt to acquire a distributed lock using Redis SET NX command
- * @param lockKey The key to use for the lock
- * @param value The value to set (e.g., a unique identifier for the process holding the lock)
- * @param expirySeconds The lock's time-to-live in seconds
- * @returns True if the lock was acquired successfully, false otherwise
+ * Attempts to acquire a lock using Redis SET NX command.
+ * @param lockKey The key to use for the lock.
+ * @param value The value to set (e.g., a unique identifier for the process holding the lock).
+ * @param expirySeconds The lock's time-to-live in seconds.
+ * @returns True if the lock was acquired successfully, false otherwise.
  */
 export async function acquireLock(
   lockKey: string,
   value: string,
   expirySeconds: number
 ): Promise<boolean> {
-  const redis = getRedisClient()
-  if (!redis) {
-    logger.warn('Redis client not available, cannot acquire lock.')
-    return false
-  }
-
   try {
+    const redis = getRedisClient()
+    if (!redis) {
+      logger.warn('Redis client not available, cannot acquire lock.')
+      // Fallback behavior: maybe allow processing but log a warning?
+      // Or treat as lock acquired if no Redis? Depends on desired behavior.
+      return true // Or false, depending on safety requirements
+    }
+
+    // Use SET key value EX expirySeconds NX
+    // Returns "OK" if successful, null if key already exists (lock held)
     const result = await redis.set(lockKey, value, 'EX', expirySeconds, 'NX')
+
     return result === 'OK'
   } catch (error) {
     logger.error(`Error acquiring lock for key ${lockKey}:`, { error })
+    // Treat errors as failure to acquire lock for safety
     return false
   }
 }
 
 /**
- * Retrieve the value of a key from Redis
- * @param key The key to retrieve
- * @returns The value of the key, or null if the key doesn't exist or an error occurs
+ * Retrieves the value of a key from Redis.
+ * @param key The key to retrieve.
+ * @returns The value of the key, or null if the key doesn't exist or an error occurs.
  */
 export async function getLockValue(key: string): Promise<string | null> {
-  const redis = getRedisClient()
-  if (!redis) {
-    logger.warn('Redis client not available, cannot get lock value.')
-    return null
-  }
-
   try {
+    const redis = getRedisClient()
+    if (!redis) {
+      logger.warn('Redis client not available, cannot get lock value.')
+      return null // Cannot determine lock value
+    }
     return await redis.get(key)
   } catch (error) {
     logger.error(`Error getting value for key ${key}:`, { error })
@@ -145,18 +211,20 @@ export async function getLockValue(key: string): Promise<string | null> {
 }
 
 /**
- * Release a lock by deleting the key
- * @param lockKey The key of the lock to release
+ * Releases a lock by deleting the key.
+ * Ideally, use Lua script for safe release (check value before deleting),
+ * but simple DEL is often sufficient if lock expiry is handled well.
+ * @param lockKey The key of the lock to release.
  */
 export async function releaseLock(lockKey: string): Promise<void> {
-  const redis = getRedisClient()
-  if (!redis) {
-    logger.warn('Redis client not available, cannot release lock.')
-    return
-  }
-
   try {
-    await redis.del(lockKey)
+    const redis = getRedisClient()
+    if (redis) {
+      await redis.del(lockKey)
+    } else {
+      logger.warn('Redis client not available, cannot release lock.')
+      // No fallback needed for releasing if using in-memory cache for locking wasn't implemented
+    }
   } catch (error) {
     logger.error(`Error releasing lock for key ${lockKey}:`, { error })
   }