FastBill

Online invoicing and billing software for freelancers and small businesses.

1 trigger7 searches26 actionsInstant (webhooks)Auth: API key

AI-assisted documentation11 min read

This documentation is compiled from our integration source code, internal specs for FastBill, its official API documentation and anonymized requests logs we collect from our support team[2].

Open FastBill on WEXTL →

Requirements

FastBill requires an active account and an API access token from your account settings to connect — both are set up on its own site.[3]

Get your FastBill credentials

Email AddressemailRequired
Your Email Address
[1]
API KeypasswordRequired
Log in to FastBill → Settings → Generate/Copy API Key.
[1]

Connect FastBill in WEXTL

Log in to your WEXTL account, add the FastBill node module to your workflow, and click Create new credential.
Instant triggers use webhooks — click Create a webhook first when adding one, then create the credential.
Optional: In the Credential name field, enter a name for the credential.
Enter the authentication credentials you copied from your FastBill account, or follow the on-screen instructions to create the credential.
If prompted, authenticate your account and confirm access.
If you want to make changes to your credential in the future, follow the steps in Manage credentials →

Connecting FastBill to WEXTL® — Video slide demonstrates how to integrate FastBill in the WEXTL visual workflow builder.[4]

Video slide demonstrates how to integrate FastBill in the WEXTL visual workflow builder.[4]

Notes

Credentials are org-scoped; share them with teammates from the Credentials picker on any of its nodes.For detailed information on connecting an application, see Connect an application →

FastBill node modules

The list below is a reference of every FastBill node module the integration supports. You will be able to pick any of them on the workflow canvas while building automations.

Browse every FastBill node module below — each one opens to show its input parameters, outputs, and connection requirements.

Watch EventsTrigger

Output fields[3]

Field	Type
User ID	number
Email address	email
Name	text
Date created	date

Get ArticlesSearch

Input fields[3]

Field	Type
Article Number	text
Limit	number

Output fields[3]

Field	Type
Article ID	text
Article number	text
Type	text
Title	text
Description	text
Unit	text
Unit price	number
Currency code	text
Vat percent	number
Is gross	number
Tags	array

Get ContactsSearch

Input fields[3]

Field	Type
Customer ID	choice
Customer Number	text
Search Term	text
Contact ID	choice
Limit	number

Output fields[3]

Field	Type
Customer ID	text
Customer number	text
Days for payment	number
Created	date
Payment type	number
Bank name	text
Bank account number	text
Bank code	text
Bank account owner	text
Bank iban	text
Bank bic	text
Bank account mandate reference	text
Show payment notice	boolean
Account receivable	text
Customer type	text
Top	text
Newsletter optin deprecated	number
Organization	text
Position	text
Academic degree	text

20other output fields

Get CustomersSearch

Input fields[3]

Field	Type
Customer IDRequired	choice
Customer Number	text
Country Code	text
City	text
Search Term	text
Limit	number

Output fields[3]

Field	Type
Customer ID	text
Customer number	text
Days for payment	number
Created	date
Payment type	number
Bank name	text
Bank account number	text
Bank code	text
Bank account owner	text
Bank iban	text
Bank bic	text
Bank account mandate reference	text
Show payment notice	boolean
Account receivable	text
Customer type	text
Top	text
Newsletter optin deprecated	number
Organization	text
Position	text
Academic degree	text

20other output fields

Get DocumentsSearch

Input fields[3]

Field	Type
Folder ID	text
Limit	number

Output fields[3]

Field	Type
Folders	array
Documents	array

Get InvoicesSearch

Input fields[3]

Field	Type
Invoice ID	choice
Invoice Number	text
Invoice Title	text
Customer ID	choice
Start Due Date	date
End Due Date	date
Start Paid Date	date
End Paid Date	date
Start Date	date
End Date	date
Payment Type	text
Start Last Update	date
End Last Update	date
Limit	number

Output fields[3]

Field	Type
Invoice ID	text
Type	text
Customer ID	text
Customer number	text
Customer costcenter ID	text
Organization	text
Salutation	text
First name	text
Last name	text
Address	text
Address 2	text
Zipcode	text
City	text
Comment	text
Payment type	number
Days for payment	number
Bank name	text
Bank account number	text
Bank code	text
Bank account owner	text

25other output fields

Get ProjectsSearch

Input fields[3]

Field	Type
Project ID	choice
Customer ID	choice

Output fields[3]

Field	Type
Project ID	text
Project name	text
Customer ID	text
Customer costcenter ID	text
Hour price	number
Currency code	text
Vat percent	number
Start date	text
End date	text
Tasks	array

Get Recurring InvoicesSearch

Input fields[3]

Field	Type
Invoice ID	choice

Output fields[3]

Field	Type
Customer ID	text
Customer number	text
Days for payment	number
Created	date
Payment type	number
Bank name	text
Bank account number	text
Bank code	text
Bank account owner	text
Bank iban	text
Bank bic	text
Bank account mandate reference	text
Show payment notice	boolean
Account receivable	text
Customer type	text
Top	text
Newsletter optin deprecated	number
Organization	text
Position	text
Academic degree	text

20other output fields

Cancel an InvoiceAction

Input fields[3]

Field	Type
Invoice IDRequired	choice

Output fields[3]

Field	Type
Status	text

Complete an InvoiceAction

Input fields[3]

Field	Type
Invoice IDRequired	choice

Output fields[3]

Field	Type
Status	text
Invoice ID	number

Create a ContactAction

Input fields[3]

Field	Type
Customer IDRequired	choice
Organization	text
Academic Degree	text
Position	text
Salutation	choice
First Name	text
Last Name	text
Address	text
Address 2	text
ZIP Code	text
City	text
Country Code	text
Secondary Address	text
Phone	text
Phone 2	text
Fax	text
Mobile	text
Email	email
VAT ID	text
Currency Code	text

2other input fields

Output fields[3]

Field	Type
Status	text
Contact ID	number

Create a CustomerAction

Input fields[3]

Field	Type
Customer TypeRequired	choice
Customer Number	text
Position	text
Academic Degree	text
Salutation	choice
Address	text
Address 2	text
Secondary Address	text
ZIP Code	text
City	text
State	text
Country Code	text
Phone	text
Phone 2	text
Fax	text
Mobile	text
Email	email
Website	url
Account Receivable	text
Currency Code	text

10other input fields

Output fields[3]

Field	Type
Status	text
Customer ID	number

Create a DocumentAction

Input fields[3]

Field	Type
Document Type	text
Title	text
Date	date
Note	text
Document	text

Output fields[3]

Field	Type
Status	text
Customer ID	number

Create a ProjectAction

Input fields[3]

Field	Type
Project NameRequired	text
Customer IDRequired	choice
Customer Cost Center ID	text
Hour Price	number
Currency Code	text
VAT Percent	number
Start Date	date
End Date	date

Output fields[3]

Field	Type
Status	text

Create a Recurring InvoiceAction

Input fields[3]

Field	Type
Customer IDRequired	choice
Start DateRequired	date
FrequencyRequired	choice
Output TypeRequired	choice
ItemsRequired	array
Customer Cost Center ID	text
Currency Code	text
Template ID	text
Introduction Text	text
Occurrences	number
Email Notify	boolean
Delivery Date	date
Cash Discount Percent	number
Cash Discount Days	number
VAT Case	boolean
Template Hash	text

Output fields[3]

Field	Type
Status	text
Invoice ID	number

Create an ArticleAction

Input fields[3]

Field	Type
Article numberRequired	text
TitleRequired	text
Unit priceRequired	number
Product type	choice
Description	text
Product unit type	text
Currency code	text
VAT Percent	number
Is Gross	choice

Output fields[3]

Field	Type
Status	text
Article ID	number

Create an InvoiceAction

Input fields[3]

Field	Type
Customer IDRequired	choice
ItemsRequired	array
Customer Cost Center ID	text
Contact ID	text
Currency Code	text
Template ID	text
Template Hash	text
Introduction Text	text
Invoice Title	text
Invoice Date	date
Delivery Date	date
Service Period Start	date
Service Period End	date
Cash Discount Percent	number
Cash Discount Days	number
VAT Case	boolean
Is Gross	boolean

Output fields[3]

Field	Type
Status	text
Invoice ID	number

Delete a ContactAction

Input fields[3]

Field	Type
Customer IDRequired	choice

Delete a CustomerAction

Input fields[3]

Field	Type
Customer IDRequired	choice

Delete a ProjectAction

Input fields[3]

Field	Type
Project IDRequired	choice

Delete a Recurring InvoiceAction

Input fields[3]

Field	Type
Recurring Invoice IDRequired	choice

Delete an ArticleAction

Input fields[3]

Field	Type
Article IDRequired	choice

Delete an InvoiceAction

Input fields[3]

Field	Type
Invoice IDRequired	choice

Lock an InvoiceAction

Input fields[3]

Field	Type
Invoice IDRequired	choice

Output fields[3]

Field	Type
Status	text

Make an API Calluniversal

Input fields[3]

Field	Type
Headers	array
Header	object
Body	text

Output fields[3]

Field	Type
Body	text
Headers	object
Status code	number

Mark an Invoice as PaidAction

Input fields[3]

Field	Type
Invoice IDRequired	choice
Date of Received Payment	date
Payment Method	text

Output fields[3]

Field	Type
Status	text
Invoice ID	number

Send an Invoice by EmailAction

Input fields[3]

Field	Type
Invoice IDRequired	choice
RecipientRequired	object
To	email
Cc	email
Bcc	email
Subject	text
Message	text
Receipt Confirmation	choice

Output fields[3]

Field	Type
Status	text

Send an Invoice by PostAction

Input fields[3]

Field	Type
Invoice IDRequired	choice

Output fields[3]

Field	Type
Status	text
Remaining Credits	text

Update a ContactAction

Input fields[3]

Field	Type
Contact IDRequired	choice
Customer ID	choice
Organization	text
Academic Degree	text
Position	text
Salutation	choice
First Name	text
Last Name	text
Address	text
Address 2	text
ZIP Code	text
City	text
Country Code	text
Secondary Address	text
Phone	text
Phone 2	text
Fax	text
Mobile	text
Email	email
VAT ID	text

3other input fields

Output fields[3]

Field	Type
Status	text
Contact ID	number

Update a CustomerAction

Input fields[3]

Field	Type
Customer IDRequired	choice
Customer Type	choice
Customer Number	text
Position	text
Academic Degree	text
Salutation	choice
Address	text
Address 2	text
Secondary Address	text
ZIP Code	text
City	text
State	text
Country Code	text
Phone	text
Phone 2	text
Fax	text
Mobile	text
Email	email
Website	url
Account Receivable	text

11other input fields

Output fields[3]

Field	Type
Status	text
Customer ID	number

Update a ProjectAction

Input fields[3]

Field	Type
Project IDRequired	choice
Project Name	text
Customer ID	choice
Customer Cost Center ID	text
Hour Price	number
Currency Code	text
VAT Percent	number
Start Date	date
End Date	date

Output fields[3]

Field	Type
Status	text

Update a Recurring InvoiceAction

Input fields[3]

Field	Type
Recurring Invoice IDRequired	choice
Customer IDRequired	choice
Start Date	date
Frequency	choice
Output Type	choice
Items	array
Customer Cost Center ID	text
Currency Code	text
Template ID	text
Introduction Text	text
Occurrences	number
Email Notify	boolean
Delivery Date	date
Cash Discount Percent	number
Cash Discount Days	number
VAT Case	boolean
Template Hash	text
Delete Existing Items	choice

Output fields[3]

Field	Type
Status	text

Update an ArticleAction

Input fields[3]

Field	Type
Article IDRequired	choice
Article number	text
Title	text
Unit price	number
Product type	choice
Description	text
Product unit type	text
Currency code	text
VAT Percent	number
Is Gross	choice

Output fields[3]

Field	Type
Status	text
Article ID	number

Update an InvoiceAction

Input fields[3]

Field	Type
Invoice IDRequired	choice
Customer ID	choice
Items	array
Customer Cost Center ID	text
Contact ID	text
Currency Code	text
Template ID	text
Template Hash	text
Introduction Text	text
Invoice Title	text
Invoice Date	date
Delivery Date	date
Service Period Start	date
Service Period End	date
Cash Discount Percent	number
Cash Discount Days	number
VAT Case	boolean
Is Gross	boolean

Output fields[3]

Field	Type
Status	text

Templates

Look for FastBill templates in the WEXTL template library.

Browse templates →

Explore alternative apps

More apps in Finance category →

References

WEXTL® FastBill Source Code connector implementation.
Our users use cases and automations.
Official API Documentation for FastBill.
WEXTL® visual workflow builder data.

Last updated: Jul 24, 2026 18:11

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