Klantly API
Connect your website, accounting software or own systems to Klantly with a secure REST API.
The Klantly API connects your own systems to your data in Klantly. Think of a website form that puts leads straight into Klantly, or accounting software that keeps your customers in sync.
What you can do
- Create, look up and update customers and leads, convert a lead into a customer, and view their timeline.
- Put deals on your pipeline board, move them, win, lose and archive them.
- Add notes to customers and deals.
- Schedule, reschedule and confirm appointments, look up free time slots and send the customer a confirmation.
- Create tasks and move them across the task board.
- Create work orders from your own systems, add photos and fetch completed work.
- Record service requests (a fault, warranty or complaint) with photos, assign them and follow the status.
- Draft quotes, mail them and record the outcome, with attachments and the PDF.
- Create and send invoices, record payments, credit them, and fetch the PDF or the payment link.
- Follow up on webshop orders: status, track and trace, and notes.
- Read along in the inbox and reply on behalf of your company via chat, WhatsApp or email.
- Fetch reviews and ask a customer for one.
- Receive a message as soon as something changes, with webhooks.
- Retrieve your users and company details.
- Test your connection and see which access your key has.
The API grows along with Klantly. New parts appear in the changelog.
At a glance
| Topic | Value |
|---|---|
| Base URL | https://app.klantly.com/api/v1 |
| Format | JSON (UTF-8) |
| Authentication | API key as a Bearer token |
| Errors | RFC 9457 (application/problem+json) |
| Language of error messages | Dutch, English, German or French |
Access
The API is available to companies with the API access feature enabled. An administrator creates keys in Klantly under Integrations → API.
Part of the API also depends on a feature in your plan: the pipeline board, appointments, tasks, work orders, quotes, invoices, the webshop, the inbox and reviews. If your plan does not include such a feature, that endpoint returns 403 with the code feature_not_available. Customers, users, company details, webhooks and events always work.
Read on
- Quickstart: your first request in five minutes.
- Authentication: keys, scopes and storing them safely.
- Webhooks: hear about every change right away.
- API reference: every endpoint with examples.
- Guides per integration: website form to lead, appointments from your planning, work orders from your ERP, invoices to your accounting and Make and n8n.
Last updated on September 27, 2026