Connect Vault to an EssentialsX economy

Vault provides an integration layer between Minecraft plugins. Installing it does not create a bank, shop or currency balance by itself. An economy provider stores balances, while a shop or rewards plugin asks that provider to make transactions through Vault. This guide uses EssentialsX as the provider.
Identify the existing economy first
Before adding anything, inspect the installed plugins and startup log. Record which plugin currently holds player balances and which plugins spend or award money. If the server already has a working provider, adding another may change which service an integration uses.
Stop the server and back up its files. Include EssentialsX player data and configuration, plus exports for external databases used by shops or other economy plugins. Keep matching copies together. A world backup alone may not preserve currency balances held elsewhere.
Install a compatible combination
Check the supported Minecraft, Java and server-platform versions for EssentialsX, Vault and the shop plugin you intend to use.
Download the plugins from their official project release links. Use the normal plugin installation process; retain a copy of any older working JAR before replacing it.
Use one intended economy provider for this setup. Do not install several providers to discover which one makes an error disappear.
Start the server once and inspect Console. Resolve dependency errors before changing prices or permissions.
A plugin reporting that it found Vault is only one part of the check. Confirm that it also found the expected economy service. Vault cannot supply another plugin's missing dependency or convert an unsupported shop into a compatible one.
Set the economy rules
Review the generated EssentialsX configuration rather than copying an unrelated server's entire file. Its economy settings include a starting balance for new players and optional command costs. Changing the starting balance is not a migration of every existing balance.
Decide who may check balances, pay other players and administer money. Administrative economy commands must remain staff-only. Grant only the relevant permission nodes using your permissions plugin, then test with a normal player instead of relying on an operator account.
Test a small transaction
Use a dedicated test account and record its opening balance. From Console, 
eco give PlayerName 10 is an example EssentialsX administrative command to add a small amount; replace the name deliberately. Verify the resulting balance in game, then make one inexpensive purchase through the actual shop.
Check both sides of the transaction: the item or reward should arrive and the correct amount should leave the same account. Repeat with insufficient funds to ensure the shop refuses the purchase. Remove temporary test funds through a recorded adjustment after testing.
If the provider is missing
Keep the existing economy data intact. Save the first relevant startup error, exact plugin versions and the shop's provider message. A permissions denial, disabled provider and database connection error need different repairs. Do not clear player data, reset balances or repeatedly replace the economy plugin to fix a dependency message. Ask support with redacted evidence if the provider cannot be identified.
Related CloudExa guides
Set up EssentialsX commands and player permissions
Connect a Minecraft plugin to a MySQL database
Further reading
Vault project and supported integrations
EssentialsX economy configuration
EssentialsX command definitions