diff --git a/server/lib/diagnostic/prosody.ts b/server/lib/diagnostic/prosody.ts
index 5f56a3ff..933f101c 100644
--- a/server/lib/diagnostic/prosody.ts
+++ b/server/lib/diagnostic/prosody.ts
@@ -1,7 +1,18 @@
+import { getWorkingDir } from '../prosody/config'
 import { newResult, TestResult } from './utils'
 
-export async function diagProsody (test: string, _options: RegisterServerOptions): Promise<TestResult> {
+export async function diagProsody (test: string, options: RegisterServerOptions): Promise<TestResult> {
   const result = newResult(test)
   result.label = 'Builtin Prosody and ConverseJS'
+
+  try {
+    const dir = await getWorkingDir(options)
+    result.messages.push('The working dir is: ' + dir)
+  } catch (error) {
+    result.messages.push('Error when requiring the working dir: ' + (error as string))
+    return result
+  }
+
+  result.ok = true
   return result
 }
diff --git a/server/lib/helpers.ts b/server/lib/helpers.ts
index 7d462e80..e4f4947a 100644
--- a/server/lib/helpers.ts
+++ b/server/lib/helpers.ts
@@ -5,20 +5,20 @@ const version: string = packagejson.version || ''
 if (!/^\d+\.\d+\.\d+/.test(version)) {
   throw new Error('Incorrect version in package.json.')
 }
-const name: string = packagejson.name || ''
-if (!/^peertube-plugin-[-a-z]+$/.test(name)) {
+const pluginName: string = packagejson.name || ''
+if (!/^peertube-plugin-[-a-z]+$/.test(pluginName)) {
   throw new Error('Incorrect plugin name in package.json.')
 }
-const shortName = name.substring('peertube-plugin-'.length)
+const pluginShortName = pluginName.substring('peertube-plugin-'.length)
 
 // FIXME: in Peertube <= 3.1.0, PeertubeHelpers dont provide this function
 function getBaseRouter (): string {
-  return '/plugins/' + shortName + '/router/'
+  return '/plugins/' + pluginShortName + '/router/'
 }
 
 // FIXME: in Peertube <= 3.1.0, PeertubeHelpers dont provide this function
 function getBaseStaticRoute (): string {
-  return '/plugins/' + shortName + '/' + version + '/static/'
+  return '/plugins/' + pluginShortName + '/' + version + '/static/'
 }
 
 // FIXME: Peertube <= 3.1.0 has no way to test that current user is admin
@@ -36,5 +36,7 @@ function isUserAdmin (res: Response): boolean {
 export {
   getBaseRouter,
   getBaseStaticRoute,
-  isUserAdmin
+  isUserAdmin,
+  pluginName,
+  pluginShortName
 }
diff --git a/server/lib/prosody/config.ts b/server/lib/prosody/config.ts
new file mode 100644
index 00000000..5f85ca68
--- /dev/null
+++ b/server/lib/prosody/config.ts
@@ -0,0 +1,116 @@
+import * as fs from 'fs'
+import { pluginName } from '../helpers'
+
+type LogMode = 'debug' | 'info'
+
+/**
+ * Creates the working dir if needed, and returns it.
+ * NB: for now, I try to create a directory in /tmp/.
+ * To ensure that there is no conflict with another peertube instance,
+ * I used a randomly generated id that will be stored in database.
+ */
+async function getWorkingDir ({ peertubeHelpers, storageManager }: RegisterServerOptions): Promise<string> {
+  const tmpBaseDir = '/tmp/'
+  await fs.promises.access(tmpBaseDir, fs.constants.W_OK) // will throw an error if no access
+  let value: string = await storageManager.getData('tempDirId')
+  while (!value) {
+    peertubeHelpers.logger.info('Generating an id for temp dir')
+    value = Math.random().toString(36).slice(2, 12)
+    const name = tmpBaseDir + pluginName + '-' + value
+    if (fs.existsSync(name)) {
+      peertubeHelpers.logger.info('The folder ' + name + ' already exists, generating another name...')
+      value = ''
+      continue
+    }
+    await storageManager.storeData('tempDirId', value)
+  }
+
+  const name = tmpBaseDir + pluginName + '-' + value
+  if (!fs.existsSync(name)) {
+    await fs.promises.mkdir(name)
+  }
+  await fs.promises.access(name, fs.constants.W_OK) // will throw an error if no access
+  return name
+}
+
+async function getProsodyConfig (_options: RegisterServerOptions): Promise<string> {
+  const peertubeDomain = 'localhost'
+  const workingDirectory = '/tmp/'
+  const logMode: LogMode = 'debug'
+  return `
+
+admins = { }
+plugin_paths = { }
+
+modules_enabled = {
+  "version"; -- Replies to server version requests
+  "uptime"; -- Report how long server has been running
+  "ping"; -- Replies to XMPP pings with pongs
+
+  "bosh"; -- Enable BOSH clients, aka "Jabber over HTTP"
+  -- "websocket"; -- XMPP over WebSockets
+
+  "posix"; -- POSIX functionality, sends server to background, enables syslog, etc.
+}
+modules_disabled = {
+    "offline"; -- Store offline messages
+    "c2s"; -- Handle client connections
+    "s2s"; -- Handle server-to-server connections
+}
+
+allow_registration = false
+
+daemonize = true;
+
+pidfile = "${workingDirectory}prosody.pid";
+
+c2s_require_encryption = false
+
+archive_expires_after = "1w" -- Remove archived messages after 1 week
+
+log = {
+  -- Log files (change 'info' to 'debug' for debug logs):
+  ${logMode} = "${workingDirectory}prosody.log";
+  error = "${workingDirectory}prosody.err";
+  -- Syslog:
+  -- { levels = { "error" }; to = "syslog";  };
+}
+
+cross_domain_bosh = false;
+consider_bosh_secure = true;
+cross_domain_websocket = false;
+consider_websocket_secure = true;
+
+VirtualHost "anon.localhost"
+  https_ports = {};
+  trusted_proxies = { "127.0.0.1", "::1" }
+
+  authentication = "anonymous"
+  allow_anonymous_s2s = false
+  modules_enabled = {
+    "http";
+    "bosh";
+    "ping";
+  }
+  http_host = "${peertubeDomain}"
+  http_external_url = "http://${peertubeDomain}"
+
+Component "room.localhost" "muc"
+  restrict_room_creation = "local"
+  muc_room_locking = false
+  muc_tombstones = false
+  muc_room_default_language = "en"
+  muc_room_default_public = true
+  muc_room_default_persistent = false
+  muc_room_default_members_only = false
+  muc_room_default_moderated = false
+  muc_room_default_public_jids = false
+  muc_room_default_change_subject = false
+  muc_room_default_history_length = 20
+`
+}
+
+export {
+  getProsodyConfig,
+  getWorkingDir
+}