diff --git a/.env.sample b/.env.sample
index 440a7de..dba9600 100644
--- a/.env.sample
+++ b/.env.sample
@@ -8,5 +8,6 @@ ETH_POLYGON_NETWORK=maticmum
 ETH_RPC=https://example.com/rpc
 ETH_RPC_MAINNET=https://example.com/rpc
 ETH_RPC_POLYGON=https://example.com/rpc
+KETL_HASHES_SOURCE=https://eth.example.com
 DOMAIN=verify.sealcred.xyz
 ENVIRONMENT=development
diff --git a/.gitignore b/.gitignore
index a1b9b5a..0ac1d8a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,4 +12,6 @@ pot/OwnershipChecker_final.zkey
 !.yarn/plugins
 !.yarn/releases
 !.yarn/sdks
-!.yarn/versions
\ No newline at end of file
+!.yarn/versions
+
+.node-persist/*
diff --git a/.gitmodules b/.gitmodules
deleted file mode 100644
index 78c25ee..0000000
--- a/.gitmodules
+++ /dev/null
@@ -1,3 +0,0 @@
-[submodule "merkleTrees"]
-	path = merkleTrees
-	url = git@github.com:BigWhaleLabs/ketl-merkle-trees.git
diff --git a/README.md b/README.md
index 92289d9..f107ff0 100644
--- a/README.md
+++ b/README.md
@@ -67,6 +67,7 @@ And you should be good to go! Feel free to fork and submit pull requests.
 | `ETH_RPC_POLYGON`     | Polygon node RPC URI (defaults to @bwl/constants)                          |
 | `DOMAIN`              | Domain name for caddy, DNS should point at the IP where the code is hosted |
 | `ENVIRONMENT`         | Environment name (defaults to `development`)                               |
+| `KETL_HASHES_SOURCE`  | Link to merkle tree hashes for Ketl                                        |
 
 Also, please, consider looking at `.env.sample`.
 
diff --git a/merkleTrees b/merkleTrees
deleted file mode 160000
index 9108984..0000000
--- a/merkleTrees
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 91089849e9439ebfa1e2ddb3ae8fb9c5985f9873
diff --git a/package.json b/package.json
index 9fe9688..ecb5fe4 100644
--- a/package.json
+++ b/package.json
@@ -23,9 +23,11 @@
     "@big-whale-labs/seal-cred-email": "^1.1.2",
     "@hapi/boom": "^10.0.0",
     "@koa/cors": "^4.0.0",
+    "@types/node-persist": "^3.1.4",
     "@zk-kit/incremental-merkle-tree": "^1.0.0",
     "amala": "^8.0.2",
     "axios": "^1.5.0",
+    "axios-cache-interceptor": "^1.3.0",
     "circomlibjs": "^0.1.7",
     "dotenv": "^16.0.3",
     "envalid": "^7.3.1",
@@ -33,6 +35,7 @@
     "koa": "^2.13.4",
     "koa-bodyparser": "^4.3.0",
     "koa-router": "^12.0.0",
+    "node-persist": "^3.1.3",
     "nodemailer": "^6.8.0",
     "uuid": "^9.0.0"
   },
diff --git a/src/controllers/verify-ketl.ts b/src/controllers/verify-ketl.ts
index 06f84ad..066d986 100644
--- a/src/controllers/verify-ketl.ts
+++ b/src/controllers/verify-ketl.ts
@@ -16,8 +16,9 @@ import Signature from '@/validators/Signature'
 import Token from '@/validators/Token'
 import TwitterBody from '@/validators/TwitterBody'
 import VerificationType from '@/models/VerificationType'
+import checkInvite from '@/helpers/ketl/checkInvite'
 import fetchUserProfile from '@/helpers/twitter/fetchUserProfile'
-import getAllowlistMap from '@/helpers/getAllowlistMap'
+import getAttestationHash from '@/helpers/signatures/getAttestationHash'
 import getBalance from '@/helpers/getBalance'
 import getEmailDomain from '@/helpers/getEmailDomain'
 import handleInvitationError from '@/helpers/handleInvitationError'
@@ -26,21 +27,19 @@ import sendEmail from '@/helpers/sendEmail'
 import signAttestationMessage from '@/helpers/signatures/signAttestationMessage'
 import zeroAddress from '@/models/zeroAddress'
 
-const allowlistMap = getAllowlistMap()
-
 @Controller('/verify-ketl')
 export default class VerifyKetlController {
   @Version('0.2.2')
   @Post('/token')
-  multipleToken(
+  async multipleToken(
     @Ctx() ctx: Context,
     @Body({ required: true }) { token, types }: AttestationTypeList & Token
   ) {
     const attestations = []
     for (const type of types) {
-      const allowlist = allowlistMap.get(type)
-      if (allowlist?.has(`token:${token}`))
-        attestations.push(signAttestationMessage(type, hexlifyString(token)))
+      const attestationHash = await getAttestationHash(hexlifyString(token))
+      const record = await signAttestationMessage(type, attestationHash)
+      if (await checkInvite(type, attestationHash)) attestations.push(record)
     }
 
     if (!attestations.length)
@@ -63,13 +62,16 @@ export default class VerifyKetlController {
     const secret = []
 
     for (const type of types) {
-      const allowlist = allowlistMap.get(type)
-      if (!allowlist?.has(`email:${email}`)) continue
-      const { message, signature } = await signAttestationMessage(
-        type,
+      const attestationHash = await getAttestationHash(
         VerificationType.email,
         hexlifyString(email)
       )
+      const { message, signature } = await signAttestationMessage(
+        type,
+        attestationHash
+      )
+      const hasInvite = await checkInvite(type, attestationHash)
+      if (!hasInvite) continue
       if (secret.length === 0) {
         const attestationHash = message[1]
         secret.push(attestationHash)
@@ -95,13 +97,12 @@ export default class VerifyKetlController {
     @Body({ required: true })
     { email, type }: AttestationType & Email
   ) {
-    const { message, signature } = await signAttestationMessage(
-      type,
+    const attestationHash = await getAttestationHash(
       VerificationType.email,
       hexlifyString(email)
     )
+    const { signature } = await signAttestationMessage(type, attestationHash)
     const domain = getEmailDomain(email)
-    const attestationHash = message[1]
 
     void sendEmail({
       domain,
@@ -126,11 +127,13 @@ export default class VerifyKetlController {
 
     const attestations = []
     for (const type of types) {
-      const allowlist = allowlistMap.get(type)
-      if (allowlist?.has(`twitter:${id}`))
-        attestations.push(
-          signAttestationMessage(type, VerificationType.twitter, id)
-        )
+      const attestationHash = await getAttestationHash(
+        VerificationType.twitter,
+        id
+      )
+      const record = await signAttestationMessage(type, attestationHash)
+      const hasInvite = await checkInvite(type, attestationHash)
+      if (hasInvite) attestations.push(record)
     }
 
     if (!attestations.length)
@@ -148,7 +151,11 @@ export default class VerifyKetlController {
     if (!user) return ctx.throw(badRequest('Failed to fetch user profile'))
     const { id } = user
 
-    return signAttestationMessage(type, VerificationType.twitter, id)
+    const attestationHash = await getAttestationHash(
+      VerificationType.twitter,
+      id
+    )
+    return signAttestationMessage(type, attestationHash)
   }
 
   @Post('/balance-unique')
@@ -194,27 +201,17 @@ export default class VerifyKetlController {
 
     const attestations = []
     for (const type of types) {
-      const allowlist = allowlistMap.get(type)
-      if (allowlist?.has(`orangedao:${signerAddress}`))
-        attestations.push(
-          signAttestationMessage(
-            type,
-            VerificationType.balance,
-            hexlifyString(signerAddress),
-            threshold,
-            hexlifyString(YC_ALUM_NFT_CONTRACT)
-          )
-        )
-      if (allowlist?.has(`bwlnft:${signerAddress}`))
-        attestations.push(
-          signAttestationMessage(
-            type,
-            VerificationType.balance,
-            hexlifyString(signerAddress),
-            threshold,
-            hexlifyString(KETL_BWL_NFT_CONTRACT)
-          )
+      for (const contract of [YC_ALUM_NFT_CONTRACT, KETL_BWL_NFT_CONTRACT]) {
+        const attestationHash = await getAttestationHash(
+          VerificationType.balance,
+          hexlifyString(signerAddress),
+          threshold,
+          hexlifyString(contract)
         )
+        const record = await signAttestationMessage(type, attestationHash)
+        const hasInvite = await checkInvite(type, attestationHash)
+        if (hasInvite) attestations.push(record)
+      }
     }
     if (!attestations.length)
       return ctx.throw(notFound(handleInvitationError('wallet')))
@@ -258,12 +255,13 @@ export default class VerifyKetlController {
       return ctx.throw(badRequest("Can't fetch the balances"))
     }
 
-    return signAttestationMessage(
-      type,
+    const attestationHash = await getAttestationHash(
       VerificationType.balance,
       hexlifyString(ownerAddress.toLowerCase()),
       threshold,
       hexlifyString(tokenAddress)
     )
+
+    return signAttestationMessage(type, attestationHash)
   }
 }
diff --git a/src/helpers/axiosWithCache.ts b/src/helpers/axiosWithCache.ts
new file mode 100644
index 0000000..a2221f3
--- /dev/null
+++ b/src/helpers/axiosWithCache.ts
@@ -0,0 +1,7 @@
+import { setupCache } from 'axios-cache-interceptor'
+import axios from 'axios'
+import buildPersistedStorage from '@/helpers/buildPersistedStorage'
+
+export default setupCache(axios, {
+  storage: buildPersistedStorage(),
+})
diff --git a/src/helpers/buildPersistedStorage.ts b/src/helpers/buildPersistedStorage.ts
new file mode 100644
index 0000000..0405217
--- /dev/null
+++ b/src/helpers/buildPersistedStorage.ts
@@ -0,0 +1,16 @@
+import { NotEmptyStorageValue, buildStorage } from 'axios-cache-interceptor'
+import { getItem, removeItem, setItem } from 'node-persist'
+
+export default function buildPersistedStorage() {
+  return buildStorage({
+    find(key: string) {
+      return getItem(key)
+    },
+    async remove(key: string) {
+      await removeItem(key)
+    },
+    async set(key: string, value: NotEmptyStorageValue) {
+      await setItem(key, value)
+    },
+  })
+}
diff --git a/src/helpers/env.ts b/src/helpers/env.ts
index cc6bc91..ba0789e 100644
--- a/src/helpers/env.ts
+++ b/src/helpers/env.ts
@@ -20,6 +20,10 @@ export default cleanEnv(process.env, {
   ETH_RPC: str({ default: ETH_RPC }),
   ETH_RPC_MAINNET: str({ default: ETH_RPC_MAINNET }),
   ETH_RPC_POLYGON: str(),
+  KETL_HASHES_SOURCE: str({
+    default:
+      'https://raw.githubusercontent.com/BigWhaleLabs/ketl-attestation-token/main',
+  }),
   PORT: num({ default: 1337 }),
   SMTP_PASS: str(),
   SMTP_USER: str(),
diff --git a/src/helpers/farcaster/connectedAddresses.ts b/src/helpers/farcaster/connectedAddresses.ts
index bffe781..077f8e6 100644
--- a/src/helpers/farcaster/connectedAddresses.ts
+++ b/src/helpers/farcaster/connectedAddresses.ts
@@ -1,5 +1,7 @@
-import axios from 'axios'
+import { isAxiosError } from 'axios'
+import axiosWithCache from '@/helpers/axiosWithCache'
 import checkIfPrimary from '@/helpers/cluster/checkIfPrimary'
+import sleep from '@/helpers/sleep'
 
 export const faddressToConnectedAddresses = {} as {
   [faddress: string]: string[]
@@ -7,11 +9,13 @@ export const faddressToConnectedAddresses = {} as {
 
 export async function fetchConnectedAddress(address: string) {
   checkIfPrimary()
-  const { data } = await axios.get<
+  const { data } = await axiosWithCache.get<
     {
       connectedAddress: string
     }[]
-  >(`https://searchcaster.xyz/api/profiles?address=${address}`)
+  >(`https://searchcaster.xyz/api/profiles?address=${address}`, {
+    id: `farcaster-profiles-${address}`,
+  })
   const connectedAddresses = data.map(
     ({ connectedAddress }) => connectedAddress
   )
@@ -36,6 +40,8 @@ export async function fetchConnectedAddresses(addresses: string[]) {
         'Error fetching connected addresses',
         error instanceof Error ? error.message : error
       )
+      if (isAxiosError(error) && error.response?.status === 429)
+        await sleep(5000)
       i -= step
     }
   }
diff --git a/src/helpers/getAllowlistMap.ts b/src/helpers/getAllowlistMap.ts
deleted file mode 100644
index 7d40043..0000000
--- a/src/helpers/getAllowlistMap.ts
+++ /dev/null
@@ -1,30 +0,0 @@
-import * as fs from 'fs'
-import { resolve } from 'path'
-import AttestationType from '@/models/AttestationType'
-
-function getAllowlist(attestationType: AttestationType) {
-  try {
-    const filePath = resolve(
-      process.cwd(),
-      'merkleTrees',
-      `${attestationType}.txt`
-    )
-    const file = fs.readFileSync(filePath, 'utf8')
-    const allowlist = file.split('\n')
-    return allowlist.filter(
-      (record: string) => !/^#/.test(record) && record !== ''
-    )
-  } catch (e) {
-    return []
-  }
-}
-
-export default function getAllowlistMap(): Map<AttestationType, Set<string>> {
-  const allowlistMap = new Map()
-  for (const type in AttestationType) {
-    const attestationType = Number(type)
-    if (isNaN(attestationType)) continue
-    allowlistMap.set(attestationType, new Set(getAllowlist(attestationType)))
-  }
-  return allowlistMap
-}
diff --git a/src/helpers/ketl/checkInvite.ts b/src/helpers/ketl/checkInvite.ts
new file mode 100644
index 0000000..f726dfd
--- /dev/null
+++ b/src/helpers/ketl/checkInvite.ts
@@ -0,0 +1,7 @@
+import getHashes from '@/helpers/ketl/getHashes'
+
+export default async function checkInvite(type: number, hash: string) {
+  const hashes = await getHashes(type)
+
+  return hashes.has(hash)
+}
diff --git a/src/helpers/ketl/getHashes.ts b/src/helpers/ketl/getHashes.ts
new file mode 100644
index 0000000..2f17b40
--- /dev/null
+++ b/src/helpers/ketl/getHashes.ts
@@ -0,0 +1,16 @@
+import axiosWithCache from '@/helpers/axiosWithCache'
+import env from '@/helpers/env'
+
+export default async function getHashes(attestationType: number) {
+  const { data } = await axiosWithCache.get<string[]>(
+    `${env.KETL_HASHES_SOURCE}/hashes/${attestationType}.json`,
+    {
+      cache: {
+        ttl: 1000 * 60 * 5, // 5 minute.
+      },
+      id: `hashes-${attestationType}`,
+    }
+  )
+
+  return new Set(data)
+}
diff --git a/src/helpers/signatures/eddsaSigPoseidon.ts b/src/helpers/signatures/eddsaSigPoseidon.ts
index c485320..77d17d4 100644
--- a/src/helpers/signatures/eddsaSigPoseidon.ts
+++ b/src/helpers/signatures/eddsaSigPoseidon.ts
@@ -6,7 +6,9 @@ import poseidonHash from '@/helpers/signatures/poseidonHash'
 const privateKey = utils.arrayify(env.EDDSA_PRIVATE_KEY)
 
 let eddsa: typeof buildEddsa
-export default async function (message: (number | BigNumber)[] | Uint8Array) {
+export default async function (
+  message: (string | number | BigNumber)[] | Uint8Array
+) {
   const hash = await poseidonHash(message)
   if (!eddsa) eddsa = await buildEddsa()
   const signature = eddsa.signPoseidon(privateKey, hash)
diff --git a/src/helpers/signatures/getAttestationHash.ts b/src/helpers/signatures/getAttestationHash.ts
new file mode 100644
index 0000000..8b7b135
--- /dev/null
+++ b/src/helpers/signatures/getAttestationHash.ts
@@ -0,0 +1,5 @@
+import poseidonHash from '@/helpers/signatures/poseidonHash'
+
+export default function getAttestationHash(...attestation: string[]) {
+  return poseidonHash(attestation, true)
+}
diff --git a/src/helpers/signatures/signAttestationMessage.ts b/src/helpers/signatures/signAttestationMessage.ts
index 5c83b36..f6e9f93 100644
--- a/src/helpers/signatures/signAttestationMessage.ts
+++ b/src/helpers/signatures/signAttestationMessage.ts
@@ -1,12 +1,10 @@
 import AttestationType from '@/models/AttestationType'
 import eddsaSigPoseidon from '@/helpers/signatures/eddsaSigPoseidon'
-import poseidonHash from '@/helpers/signatures/poseidonHash'
 
 export default async function signAttestationMessage(
   attestationType: AttestationType,
-  ...attestation: string[]
+  attestationHash: string
 ) {
-  const attestationHash = await poseidonHash(attestation, true)
   const message = [attestationType, attestationHash]
   const signature = await eddsaSigPoseidon(message)
 
diff --git a/src/helpers/sleep.ts b/src/helpers/sleep.ts
new file mode 100644
index 0000000..0179fd0
--- /dev/null
+++ b/src/helpers/sleep.ts
@@ -0,0 +1,3 @@
+export default function sleep(time = 1000) {
+  return new Promise((res) => setTimeout(res, time))
+}
diff --git a/src/server.ts b/src/server.ts
index 5c0371b..94e1faf 100644
--- a/src/server.ts
+++ b/src/server.ts
@@ -2,14 +2,20 @@ import 'module-alias/register'
 import 'source-map-support/register'
 
 import * as os from 'os'
+import { init as initStorage } from 'node-persist'
 import { isAddressConnected } from '@/helpers/farcaster/connectedAddresses'
 import Cluster from '@/helpers/cluster/cluster'
+import axiosWithCache from '@/helpers/axiosWithCache'
+import buildPersistedStorage from '@/helpers/buildPersistedStorage'
 import prepareFarcaster from '@/helpers/farcaster/prepareFarcaster'
 import runApp from '@/helpers/runApp'
 
 const totalCPUs = os.cpus().length
 
-void (() => {
+void (async () => {
+  await initStorage()
+  axiosWithCache.storage = buildPersistedStorage()
+
   if (Cluster.isPrimary) {
     console.log(`Number of CPUs is ${totalCPUs}`)
     console.log(`Primary ${process.pid} is running`)
diff --git a/yarn.lock b/yarn.lock
index f4263f9..1cf99b6 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1281,6 +1281,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@types/node-persist@npm:^3.1.4":
+  version: 3.1.4
+  resolution: "@types/node-persist@npm:3.1.4"
+  dependencies:
+    "@types/node": "*"
+  checksum: b81a13f37550d9f365b75579b34167cfb7a2d9b0784f43b66c2d5f309f6f547ab31f07bf7d68cbb63adbf8c7a2390db397017e118d29e3dd82b2d6a4122e3151
+  languageName: node
+  linkType: hard
+
 "@types/node@npm:*":
   version: 18.0.0
   resolution: "@types/node@npm:18.0.0"
@@ -1725,11 +1734,13 @@ __metadata:
     "@types/koa-router": ^7.4.4
     "@types/koa__cors": ^3.3.0
     "@types/node": ^18.11.9
+    "@types/node-persist": ^3.1.4
     "@types/nodemailer": ^6.4.6
     "@types/uuid": ^8.3.4
     "@zk-kit/incremental-merkle-tree": ^1.0.0
     amala: ^8.0.2
     axios: ^1.5.0
+    axios-cache-interceptor: ^1.3.0
     circomlibjs: ^0.1.7
     dotenv: ^16.0.3
     envalid: ^7.3.1
@@ -1739,6 +1750,7 @@ __metadata:
     koa-bodyparser: ^4.3.0
     koa-router: ^12.0.0
     module-alias: ^2.2.2
+    node-persist: ^3.1.3
     nodemailer: ^6.8.0
     prettier: ^2.8.0
     source-map-support: ^0.5.21
@@ -1755,6 +1767,19 @@ __metadata:
   languageName: node
   linkType: hard
 
+"axios-cache-interceptor@npm:^1.3.0":
+  version: 1.3.0
+  resolution: "axios-cache-interceptor@npm:1.3.0"
+  dependencies:
+    cache-parser: ^1.2.4
+    fast-defer: ^1.1.7
+    object-code: ^1.3.0
+  peerDependencies:
+    axios: ^1
+  checksum: 000138670d97a9bcddf996a4c1b87f186712c9bd4a1ac2ef7a0d49ee1965110923343226596e7419f153945f46ab1aece6fef64aca53836312f3949f4a674aca
+  languageName: node
+  linkType: hard
+
 "axios@npm:^1.5.0":
   version: 1.5.0
   resolution: "axios@npm:1.5.0"
@@ -1973,6 +1998,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"cache-parser@npm:^1.2.4":
+  version: 1.2.4
+  resolution: "cache-parser@npm:1.2.4"
+  checksum: de9fc4ab7af318109f1e53474e674d43997bc7b8676157e4f28e7dc60fda2f434ee138aa9d9abb9f849c55e73202ee74865afaa4e00298de70c4326510680c19
+  languageName: node
+  linkType: hard
+
 "call-bind@npm:^1.0.0, call-bind@npm:^1.0.2":
   version: 1.0.2
   resolution: "call-bind@npm:1.0.2"
@@ -3251,6 +3283,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"fast-defer@npm:^1.1.7":
+  version: 1.1.7
+  resolution: "fast-defer@npm:1.1.7"
+  checksum: c0f816fe3f83ca7e12c56a6631c6819a50349fb7e1931cec88e883168b523c65605e6e0df32c8fba6c341860c29ecc6fe2531ba8a418d27d31da6544ad1bf45b
+  languageName: node
+  linkType: hard
+
 "fast-diff@npm:^1.1.2":
   version: 1.2.0
   resolution: "fast-diff@npm:1.2.0"
@@ -5254,6 +5293,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"node-persist@npm:^3.1.3":
+  version: 3.1.3
+  resolution: "node-persist@npm:3.1.3"
+  checksum: a67d1f7e646e9926558237b4f30a50cc73ae9e58a1be28fb87203b0b7180b7f7178c380f74229900c62cf7ee139e00c4c8bd5abcbb82e91326d8eb7938a827a9
+  languageName: node
+  linkType: hard
+
 "nodemailer@npm:^6.8.0":
   version: 6.8.0
   resolution: "nodemailer@npm:6.8.0"
@@ -5307,6 +5353,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"object-code@npm:^1.3.0":
+  version: 1.3.0
+  resolution: "object-code@npm:1.3.0"
+  checksum: bc5e3df85ac54785b3d1d9b8a9b2e168eb5f69e02be3c958fc05aebaa85ec659c55903852bf15ebf44e98053212f88eb7d3a9e28a50f10c4d60d820f80aa8d64
+  languageName: node
+  linkType: hard
+
 "object-inspect@npm:^1.12.0, object-inspect@npm:^1.9.0":
   version: 1.12.2
   resolution: "object-inspect@npm:1.12.2"