diff --git a/.gitignore b/.gitignore
index 5e11828..bf9d950 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
 .env
 .DS_Store
 /node_modules
+/store
diff --git a/index.mjs b/index.mjs
new file mode 100644
index 0000000..024ef76
--- /dev/null
+++ b/index.mjs
@@ -0,0 +1,47 @@
+import { XrplClient } from 'xrpl-client'
+import { createDirectory } from './lib/createDirectory.mjs'
+import { onValidation } from './lib/onValidation.mjs'
+// import { onLedger } from './lib/onLedger.mjs'
+// import { onTransaction } from './lib/onTransaction.mjs'
+import 'dotenv/config'
+import assert from 'assert'
+
+assert(process.env?.NODES, 'ENV var missing: NODES, containing: a comma separated list of websocket endpoints')
+
+await createDirectory('store')
+
+process.env.NODES.split(',').map(h => h.trim())
+  .map(h => new XrplClient(h)).map(async c => {
+    await c.ready()
+
+    /**
+     * TODO: Auto disconnect if no messages for X
+     */
+
+    c.send({ command: "subscribe", streams: [
+      "validations",
+      // "ledger",
+      // "transactions",
+      // "transactions_proposed"
+    ] })
+
+    c.on("validation", validation => onValidation({
+      connectionUrl: c.getState()?.server?.uri,
+      networkId: c.getState()?.server?.networkId,
+      validation,
+    }))
+
+    // c.on("ledger", ledger => onLedger({
+    //   connectionUrl: c.getState()?.server?.uri,
+    //   networkId: c.getState()?.server?.networkId,
+    //   ledger,
+    //   connection: c,
+    // }))
+
+    // c.on("transaction", transaction => onTransaction({
+    //   connectionUrl: c.getState()?.server?.uri,
+    //   networkId: c.getState()?.server?.networkId,
+    //   transaction,
+    //   connection: c,
+    // }))
+  })
diff --git a/lib/createDirectory.mjs b/lib/createDirectory.mjs
new file mode 100644
index 0000000..13ee304
--- /dev/null
+++ b/lib/createDirectory.mjs
@@ -0,0 +1,22 @@
+import { URL } from 'url'
+import { mkdir, stat } from 'fs'
+
+const createDirectory = dir => new Promise((resolve, reject) => {
+  const dirToCreate = new URL('../' + dir, import.meta.url).pathname
+  stat(dirToCreate, staterr => {
+    if (staterr) {
+      mkdir(dirToCreate, { recursive: true }, mkerr => {
+        if (mkerr) {
+          reject(new Error('Error creating Store directory: ' + staterr?.message + ' » ' + mkerr?.message))
+        }
+        resolve(dirToCreate)
+      })
+    } else{
+      resolve(dirToCreate)
+    }
+  })  
+})
+
+export {
+  createDirectory,
+}
diff --git a/lib/fetchUnl.mjs b/lib/fetchUnl.mjs
new file mode 100644
index 0000000..94eccc9
--- /dev/null
+++ b/lib/fetchUnl.mjs
@@ -0,0 +1,138 @@
+/**
+ * Richard Holland, XRPL Labs, 2021
+ * Originally part of https://github.com/RichardAH/xpop-generator/tree/master
+ */
+
+import elliptic from 'elliptic'
+const ed25519 = elliptic.eddsa('ed25519')
+import fetch from 'node-fetch'
+import address from 'ripple-address-codec'
+
+const fetchUnl = (url, master_public_key) => {
+  return new Promise(async (resolve, reject) => {
+    const codec = { address, }
+    const assert = (c, m) => {
+      if (!c) reject("Invalid manifest: " + (m ? m : ""));
+    }
+
+    const parse_manifest = buf => {
+      let man = {}
+      let upto = 0
+
+      let verify_fields = [Buffer.from('MAN\x00', 'utf-8')];
+      let last_signing = 0;
+
+      // sequence number
+      assert(buf[upto++] == 0x24, "Missing Sequence Number")
+      man['Sequence'] = (buf[upto] << 24) + (buf[upto+1] << 16) + (buf[upto+2] << 8) + buf[upto+3]
+      upto += 4
+
+      // public key
+      assert(buf[upto++] == 0x71, "Missing Public Key")       // type 7 = VL, 1 = PublicKey
+      assert(buf[upto++] == 33, "Missing Public Key size")    // one byte size
+      man['PublicKey'] = buf.slice(upto, upto + 33).toString('hex')
+      upto += 33
+
+      // signing public key
+      assert(buf[upto++] == 0x73, "Missing Signing Public Key")       // type 7 = VL, 3 = SigningPubKey
+      assert(buf[upto++] == 33, "Missing Signing Public Key size")    // one byte size
+      man['SigningPubKey'] = buf.slice(upto, upto + 33).toString('hex')
+      upto += 33
+
+      // signature
+      verify_fields.push(buf.slice(last_signing, upto))
+      assert(buf[upto++] == 0x76, "Missing Signature")    // type 7 = VL, 6 = Signature
+      let signature_size = buf[upto++];
+      man['Signature'] = buf.slice(upto, upto + signature_size).toString('hex')
+      upto += signature_size
+      last_signing = upto
+
+      // domain field | optional
+      if (buf[upto] == 0x77) {
+        upto++
+        let domain_size = buf[upto++]
+        man['Domain'] = buf.slice(upto, upto + domain_size).toString('utf-8')
+        upto += domain_size
+      }
+
+      // master signature
+      verify_fields.push(buf.slice(last_signing, upto))
+      assert(buf[upto++] == 0x70, "Missing Master Signature lead byte")   // type 7 = VL, 0 = uncommon field
+      assert(buf[upto++] == 0x12, "Missing Master Signature follow byte") // un field = 0x12 master signature
+      let master_size = buf[upto++];
+      man['MasterSignature'] = buf.slice(upto, upto + master_size).toString('hex')
+      upto += master_size
+      last_signing = upto // here in case more fields ever added below
+
+      assert(upto == buf.length, "Extra bytes after end of manifest")
+
+      // for signature verification
+      man.without_signing_fields = Buffer.concat(verify_fields)
+      return man;
+    }
+
+    const unlData = await fetch(url)
+    const json = await unlData.json()
+
+    // initial json validation
+    assert(json.public_key !== undefined, "public key missing from vl")
+    assert(json.signature !== undefined, "signature missing from vl")
+    assert(json.version !== undefined, "version missing from vl")
+    assert(json.manifest !== undefined, "manifest missing from vl")
+    assert(json.blob !== undefined, "blob missing from vl")
+    assert(json.version == 1, "vl version != 1")
+
+    // check key is recognised
+    if (master_public_key)
+        assert(json.public_key.toUpperCase() == master_public_key.toUpperCase(),
+            "Provided VL key does not match")
+    else
+        master_public_key = json.public_key.toUpperCase()
+
+    // parse blob
+    let blob = Buffer.from(json.blob, 'base64')
+
+    // parse manifest
+    const manifest = parse_manifest(Buffer.from(json.manifest, 'base64'))
+
+    // verify manifest signature and payload signature
+    const master_key = ed25519.keyFromPublic(master_public_key.slice(2), 'hex')
+    assert(master_key.verify(manifest.without_signing_fields, manifest.MasterSignature),
+        "Master signature in master manifest does not match vl key")
+    let signing_key = ed25519.keyFromPublic(manifest.SigningPubKey.slice(2), 'hex')
+    assert(signing_key.verify(blob.toString('hex'), json.signature),
+        "Payload signature in mantifest failed verification")
+    blob = JSON.parse(blob)
+
+    assert(blob.validators !== undefined, "validators missing from blob")
+
+    // parse manifests inside blob (actual validator list)
+    let unl = {}
+    for (let idx in blob.validators) {
+      assert(blob.validators[idx].manifest !== undefined,
+        "validators list in blob contains invalid entry (missing manifest)")
+      assert(blob.validators[idx].validation_public_key !== undefined,
+        "validators list in blob contains invalid entry (missing validation public key)")
+    
+      let manifest = parse_manifest(Buffer.from(blob.validators[idx].manifest, 'base64'))
+
+      // verify signature
+      signing_key = ed25519.keyFromPublic(blob.validators[idx].validation_public_key.slice(2), 'hex')
+
+      assert(signing_key.verify(manifest.without_signing_fields, manifest.MasterSignature),
+        "Validation manifest " + idx + " signature verification failed")
+
+      blob.validators[idx].validation_public_key = Buffer.from(blob.validators[idx].validation_public_key, 'hex')
+      blob.validators[idx].manifest = manifest
+      
+      let nodepub = codec.address.encodeNodePublic(Buffer.from(manifest.SigningPubKey, 'hex'))
+      unl[nodepub] = manifest.SigningPubKey
+    }
+
+    resolve({unl: {...unl}, vl: json})
+  })
+}
+
+export {
+  fetchUnl,
+}
diff --git a/lib/ledgerIndexToFolders.mjs b/lib/ledgerIndexToFolders.mjs
new file mode 100644
index 0000000..6ec950d
--- /dev/null
+++ b/lib/ledgerIndexToFolders.mjs
@@ -0,0 +1,9 @@
+const ledgerIndexToFolders = ledgerIndex => {
+  return Math.floor(ledgerIndex / Math.pow(10, 6)) + '/'
+    + Math.floor((ledgerIndex % Math.pow(10, 6)) / Math.pow(10, 3)) + '/'
+    + ledgerIndex % Math.pow(10, 6) % Math.pow(10, 3)
+}
+
+export {
+  ledgerIndexToFolders
+}
diff --git a/lib/onValidation.mjs b/lib/onValidation.mjs
new file mode 100644
index 0000000..b59a2ad
--- /dev/null
+++ b/lib/onValidation.mjs
@@ -0,0 +1,75 @@
+import { writeFile } from 'fs'
+import { createDirectory } from './createDirectory.mjs'
+import 'dotenv/config'
+import { unlData } from './unlData.mjs'
+import { ledgerIndexToFolders } from './ledgerIndexToFolders.mjs'
+
+const lastSeenValidations = []
+let lastCreatedLedgerDir
+
+const onValidation = async ({
+  connectionUrl,
+  networkId,
+  validation,
+}) => {
+  /**
+   * Only proceed if the pubkey is on preferred UNL & reported by node with expected network ID
+   */
+  if (unlData.hosts.indexOf(validation.validation_public_key) > -1 && networkId === unlData.networkid) {
+    unlData.refresh()
+ 
+    const lastSeenKey = `${validation.ledger_index} @ ${validation.validation_public_key}`
+
+    /**
+     * Do not process & write same validation received from multiple nodes twice
+     */
+    if (lastSeenValidations.indexOf(lastSeenKey) < 0) {
+
+      lastSeenValidations.unshift(lastSeenKey)
+      lastSeenValidations.length = unlData.hosts.length * 10
+
+      /**
+       * Write to ledger index folder
+       */
+      const relativeStorDir = 'store/' + networkId + '/' + ledgerIndexToFolders(validation.ledger_index)
+      const storeDir = new URL('../' + relativeStorDir, import.meta.url).pathname
+
+      if (lastCreatedLedgerDir !== validation.ledger_index) {
+        await createDirectory(relativeStorDir)
+        lastCreatedLedgerDir = validation.ledger_index
+
+        writeFile(storeDir + '/vl.json', Buffer.from(JSON.stringify(unlData.data), 'utf8'), err => {
+          if (err) {
+            console.log('Error writing file @ ' + storeDir)
+          }
+        })  
+      }
+
+      /**
+       * Debug output
+       */
+      console.log(
+        networkId,
+        validation.ledger_index,
+        relativeStorDir,
+        validation.validation_public_key,
+        // validation.validated_hash, // parent hash
+        validation.ledger_hash, // ledger_hash
+        connectionUrl,
+      )
+
+      /**
+       * Create validation file
+       */
+      writeFile(storeDir + '/' + validation.validation_public_key + '.json', Buffer.from(JSON.stringify(validation), 'utf8'), err => {
+        if (err) {
+          console.log('Error writing file @ ' + storeDir)
+        }
+      })
+    }
+  }
+}
+
+export {
+  onValidation,
+}
diff --git a/lib/unlData.mjs b/lib/unlData.mjs
new file mode 100644
index 0000000..0973a96
--- /dev/null
+++ b/lib/unlData.mjs
@@ -0,0 +1,61 @@
+import { fetchUnl } from './fetchUnl.mjs'
+import 'dotenv/config'
+import assert from 'assert'
+
+const unlCacheTimeSec = 120
+
+class UNL {
+  data = {}
+  hosts = {}
+  networkid = 0
+  updated = null
+  fetching = false
+
+  constructor () {
+    assert(process.env?.UNLURL, 'ENV var missing: UNLURL, containing: the URL of the Validator List')
+    assert(process.env?.UNLKEY, 'ENV var missing: UNLKEY, containing: the signing (pub) key for the Validator List')
+    assert(process.env?.NETWORKID, 'ENV var missing: NETWORKID, containing: the network ID (int), e.g. 0 for mainnet')
+
+    this.networkid = Number(process.env.NETWORKID)
+
+    this.fetch()
+  }
+
+  async refresh () {
+    const timeDiffSec = Math.floor((new Date() - this.updated) / 1000)
+
+    if (timeDiffSec > unlCacheTimeSec && !this.fetching) {
+      return await this.fetch()
+    }
+    
+    return Promise.resolve()
+  }
+
+  async fetch () {
+    this.fetching = true
+
+    try {
+      const unl = await fetchUnl(process.env.UNLURL, process.env.UNLKEY)
+      const unlHosts = Object.keys(unl.unl)
+      console.log('Fetched UNL', process.env.UNLURL, 'found validators', unlHosts.length)
+
+      if (unlHosts.length > 1) {
+        this.data = unl
+        this.hosts = unlHosts
+        this.updated = new Date()
+      }
+    } catch (e) {
+      this.fetching = false
+      return e
+    }
+
+    this.fetching = false
+    return
+  }
+}
+ 
+const unlData = new UNL()
+
+export {
+  unlData,
+}
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..5ac633a
--- /dev/null
+++ b/package.json
@@ -0,0 +1,24 @@
+{
+  "name": "xrplp-validation-msg-store",
+  "version": "1.0.0",
+  "description": "Store XRPL Proof of Validation messages",
+  "main": "index.mjs",
+  "scripts": {
+    "dev": "nodemon ."
+  },
+  "author": "Wietse Wind <w@xrpl-labs.com>",
+  "license": "MIT",
+  "nodemonConfig": {
+    "ignore": [
+      "store/*"
+    ]
+  },
+  "dependencies": {
+    "dotenv": "^16.3.1",
+    "ed25519": "^0.0.5",
+    "elliptic": "^6.5.4",
+    "node-fetch": "^3.3.2",
+    "ripple-address-codec": "^4.3.0",
+    "xrpl-client": "^2.2.0"
+  }
+}
diff --git a/store/.gitkeep b/store/.gitkeep
new file mode 100644
index 0000000..e69de29