Connecting Yuki

Prerequisites

• An active Yuki account on the Business Plan (API access is not available on free plans)
• Portal Administrator or Management role (required to generate an API key)
• Your Yuki administration ID (a GUID)

Steps

1. Get your API Key (WebserviceAccessKey)

   • Log in to Yuki at yuki.nl or yuki.be
   • Navigate to Settings > Web service access code
   • Generate a new API key (or copy the existing one)
   • See Yuki's guide

2. Find your Administration ID

   • Your Yuki administrator can provide this
   • It's a GUID (e.g., a1b2c3d4-e5f6-7890-abcd-ef1234567890)
   • If unsure, ask Yuki support or check the Administrations API method

3. (Optional) Find your Domain ID

   • Required for customer/supplier operations on Yuki environments where the Domain GUID differs from the Administration GUID
   • Your Yuki administrator can provide this — it's a GUID
   • If omitted, the connection falls back to using the Administration ID

4. Configure the connection

   • Enter your API Key (WebserviceAccessKey)
   • Enter your Administration ID
   • (Optional) Enter your Domain ID
   • Select your Region (Netherlands or Belgium)
   • Click Save

Settings

Setting	Required	Description
API Key	Yes	Your WebserviceAccessKey from Yuki admin settings
Administration ID	Yes	The GUID of the Yuki administration to connect
Domain ID	No	Optional — GUID of the Yuki domain. Required for customer/supplier operations on multi-domain setups. Falls back to the Administration ID when left empty.
Region	Yes	Netherlands (api.yukiworks.nl) or Belgium (api.yukiworks.be)

Rate Limits

Plan	Calls/day
Default	1,000
Yuki Webservice	5,000
Yuki Webservice Extended	10,000

Each API operation uses 2 calls (authenticate + request), so effective capacity is half the listed limit.

Troubleshooting

Issue	Solution
"Authentication failed"	Verify your API key is correct and not expired
"No data returned"	Check that the Administration ID matches an active administration
Empty responses	Ensure the selected administration has data (invoices, contacts, etc.)
403/Forbidden	Confirm your Yuki account is on the Business Plan with API access
"Invalid domain ID" on customers/suppliers	Set the Domain ID setting to the correct GUID (see step 3)
Customer/supplier list empty despite created contacts	Yuki only flags a contact as a customer/supplier after their first invoice is created. Use the invoices endpoint to create an invoice for the contact, then the list will return it.