FastBill Integration

Online invoicing and billing software for freelancers and small businesses. Connect FastBill financial events to workflows that update records and notify the right teams. Start from Watch Events, then automate actions such as Get Articles and Get Contacts.

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Supported triggers and actions for FastBill integration

Triggers can detect changes in FastBill and run actions that can create, search or modify data inside FastBill automatically [3] — exactly how you set them.

Watch EventsTriggers when a new event occurs.
Get ArticlesRetrieves all articles from the service.
Get ContactsRetrieves all contacts.
Get CustomersRetrieves all customers.
Get DocumentsRetrieves all documents from the service.
Get InvoicesRetrieves all invoices.
Get ProjectsRetrieves all projects.
Get Recurring InvoicesRetrieves all recurring invoices.
Cancel an InvoiceCancels an invoice.
Complete an InvoiceMarks an invoice as completed and updates its status in the system.
Create a ContactCreates a new contact in the specified service.
Create a CustomerCreates a customer in the system.
Create a DocumentCreates a new document in the specified service.
Create an ArticleCreates a new article.
Create an InvoiceCreates an invoice with specified details in the service.
Create a ProjectCreates a new project in the selected service.
Create a Recurring InvoiceCreates a recurring invoice based on the provided parameters.
Delete a ContactDeletes a contact from the specified service.
Delete a CustomerDeletes a customer from the service.
Delete an ArticleDeletes an article from the service.
Delete an InvoiceDeletes an invoice from the system.
Delete a ProjectDeletes a project from the service.
Delete a Recurring InvoiceDeletes a recurring invoice from the system.
Lock an InvoiceLocks an invoice to restrict its modifications.
Make an API CallPerforms an arbitrary authorized API call.
Mark an Invoice as PaidMarks an invoice as paid in the system.
Send an Invoice by EmailSends an invoice to a recipient via email.
Send an Invoice by PostSends an invoice by post to a specified recipient.
Update a ContactUpdates a contact in the system with the specified details.
Update a CustomerUpdates a customer's information.
Update an ArticleUpdates an article in the system.
Update an InvoiceUpdates an invoice with new information or changes.
Update a ProjectUpdates a project with new information, such as details, status, or contributors.
Update a Recurring InvoiceUpdates a recurring invoice with new details.

How to integrate FastBill in automation workflow?

3 simple steps to make your FastBill connected with other apps in automation workflows on WEXTL. Up to 10 minutes integration set up.

STEP 1

Select FastBill in workflow

Pick FastBill app in the workflow builder [4] - just one click to select the app.

STEP 2

Connect FastBill

When prompted, authorize access to FastBill in WEXTL once. FastBill credentials are encrypted and never shared with WEXTL. Authorization will be reused in any future API calls [3].

WEXTL wants to integrate with your FastBill account. Approve?

STEP 3

Build a workflow

Build your workflow with FastBill yourself or with WEXTL® AI Builder. Connect FastBill to any available integrations [5], or use HTTP node to go beyond them.

FastBill

How FastBill connects and integrates with WEXTL

Save and approve your credentials once — WEXTL® stores authorization information encrypted and reuses the authentication whenever FastBill app is called in workflows. That allows your finance automations to run without your attention, per defined schedule [7]. Explore documentation [6] for a detailed list of fields that FastBill supports.

Full FastBill API documentation

The following table illustrates what fields FastBill integration require during authorization flow inside our workflow builder [4].

Video slide demonstrates how FastBill is connected in WEXTL builder [4].

Field	Type	Help
Email AddressRequired	email	Your Email Address
API KeyRequired	password	Log in to FastBill → Settings → Generate/Copy API Key.

Connect FastBill to popular apps on WEXTL

Enter a name of the other app you want to sync with FastBill below. Click on selected app to explore integration options with FastBill. If the app you search for is not available in WEXTL yet, you can use HTTP node [10] instead to integrate it directly.

Example automation with FastBill integration

Select Watch Events trigger from FastBill - this will be a starting point in your automation. Whenever event happens in FastBill, workflow will start [7] from Watch Events node.

Search for Create a Contact, connect it as the next step of integration sequence. You can use filters between Watch Events and Create a Contact, so only important data pass from Watch Events to the next step. WEXTL gives you full control over the process of FastBill automation. All parts of workflow are visible on the canvas [4].

FastBill on WEXTL has 34 modules for building finance automations. Explore FastBill documentation for more.

Video slide demonstrates how Watch Events and Create a Contact nodes are used in FastBill workflow.

Video slide demonstrates how Watch Events and Create a Contact [6] nodes are used in FastBill workflow.

Frequently asked questions

Common questions about automating FastBill in your workflows.

FastBill has 1 trigger, including "Watch Events". Triggers are start points of the workflow, and automations may start from them.

Integration has 33 actions, including "Get Articles", "Get Contacts", and "Get Customers", and more. Refer to our FastBill Documentation for detailed inputs and outputs.

No. Most automations are built visually on the canvas by picking triggers, actions, and mapping fields. You can add custom JavaScript with Functions when advanced logic is needed — but our customers do that in rare cases [4].

Yes. Connections are authenticated per account, credentials are encrypted at rest, and you can enforce approvals and team-level access controls on any automation.

The FastBill integration on WEXTL runs directly on its vendor public API — every field name, authentication method, and rate limit is controlled by FastBill official API and covered in documentation [3]. WEXTL handles the request signing and pagination for you.

Absolutely. Where FastBill provides native webhooks, you can use instant triggers to eliminate polling delay. For custom webhooks, WEXTL offers Custom Webhook node, so you can start automation whenever FastBill or any other service sends event to webhook URL.

WEXTL is an AI-first visual canvas. The platform allows you to describe automation in plain text — and AI will wire nodes for FastBill inside the workflow builder [4]. You can also use built-in workflow nodes (AI Agent, Human in the Loop, Condition, Aggregate Results) in pair with FastBill modules to craft complex integration flows with branches, filtering, and conditional logic. There are absolutely no limits of what you can build.

References

List of sources used to gather information about the FastBill integration.

FastBill integration source code, module specs and credentials implementation.
Internal FastBill integration documentation, structured input and output parameters, scopes, and authentication methods.
Official FastBill vendor API documentation — used to verify field meanings, authentication flows, and anything our own specs don't fully capture.
WEXTL® Visual Workflow Builder, anonymized data from our technical support team.
WEXTL® Apps Library
WEXTL® FastBill App Documentation
WEXTL® Workflow Scheduler
WEXTL® HTTP node documentation

FastBill Integration

Supported triggers and actions for FastBill integration