Fynn Functions

Fynn Functions allows developers to extend the behavior of backend logic. Here you will learn how to set up and use Fynn Functions.

This extension is currently in a closed beta phase. Please contact us to get access.

How does Fynn Functions work?

Fynn Functions allows you to write custom functions that respond to events in Fynn. For this, we provide various extension points that you can use to write custom logic. If one or more functions are registered for an extension point, they are executed when the corresponding event occurs. A context object is passed that contains information about the event, which could be a cart, for example. Within the function, you can then perform any actions, such as calling an external API. Each function must return one or more predefined operations at the end, which are then executed by Fynn.

Each extension point has different context objects and operations that you can use.

Runtimes

Each function is executed in an isolated environment limited to 5 seconds. Please note that the runtime of a function directly affects Fynn’s response time.

Functionality in Fynn Functions

Within Fynn Functions, you can use all JavaScript functions that are also available in the browser.

Extension Points

Fynn Functions currently supports the following extension points:

Checkout: checkout.cart.delivery, checkout.cart.cart_item_option

Add Shipping Costs

The checkout.cart.delivery extension point can be used to add shipping costs to the cart. If the price of the shipping costs is one-time, it is only calculated in the 1st invoice and is not recurring. Otherwise, the price of the shipping costs is calculated in every invoice.

Context Object

DeliveryContext

Show properties

CartPublic

The current cart of the user

string

The country code of the delivery country, taking into account the billing and delivery address of the cart.

Operations

AddDelivery

Show properties

string

The product ID to be added as shipping costs.

string

required

The price plan to be used for the shipping costs. If none is specified, the 1st price in the product is used.

Example

function run (input) {
    const countryCode = input?.deliveryCountryCode;
    const itemsCount = input?.cart?.items.length;

  if (itemsCount === 0) return [];

    if (countryCode === 'DE') {
        return [{
            __type: 'checkout:add_delivery',
            product: '14937550-26d0-454a-b4d4-64eabac67663'
        }];
    }

    if (countryCode === 'CH') {
        return [{
            __type: 'checkout:add_delivery',
            product: '5a7f267a-087b-4bdf-a620-79a4e2942545'
        }];
    }

    // more custom logic, e.g. by zip, best price, etc.

    return [];
}

Add Product Options

The checkout.cart.cart_item_option extension point can be used to display selection options in the cart on the product.

Context Object

CartItemProductInput

Show properties

string

The ID of the product

string

The product number, if specified. Otherwise, this is null.

array

Values of the custom attributes of the product.

CartItemInput

Show properties

CartPublicItem

The current product / cart item in the cart

CartItemProductInput

The current product ID

Operations

AddCartItemOptionSet

Show properties

string

required

The product for which the options should be added.

string

required

The name of the option selection, which is available in the webhook.

string

required

The name of the option selection, which is displayed in the checkout.

array

required

The options available for selection.

Alternatively, product options can be added based on a custom attribute in the product.

AddCustomFieldListAsOptionSet

Show properties

string

required

The name of the option selection, which is available in the webhook.

string

required

The name of the option selection, which is displayed in the checkout.

string

required

The field that must be available in the product as a custom attribute (Type: List), to display its list options.

string

required

Regex to preselect a list option as default. E.g., /.* \(Current\)/i (must contain (Current)).

Show properties

boolean

default:"false"

Whether the option is preselected.

string

required

The name of the option, which is displayed in the checkout.

string

required

The value of the option, which is available in the webhook.

Example

function run(input) {
  return [
    {
      __type: 'checkout:add_cart_item_option_set',
      product: '0ba377f0-d9e9-4338-a107-9209a6e0f1fb',
      name: 'from Issue',
      label: 'from Issue',
      options: [
        {
          label: 'No. 24',
          value: '24'
        },
        {
          label: 'No. 25',
          value: '25',
          preselected: true,
        },
        {
          label: 'No. 26',
          value: '26'
        },
      ]
    }
  ];
}

Register Function

To register a function, create a support ticket to get access to Fynn Functions.

Global Context Objects

export type CartItemProduct

export type CartPublicCustomerAddress = {
  id: string;
  firstName?: string;
  lastName?: string;
  companyName?: string;
  street: string;
  houseNumber?: string;
  zip: string;
  city: string;
  addition?: string;
  countryCode: string;
  costCentre?: string;
  vatId?: string;
}

export type CartPublicItem = {
  name: string;
  description?: string;
  quantity: number;
  type: 'product' | 'plan' | 'delivery';
  id: string;
  product: {
      id: string;
      number: string | null;
      customFields: Record<string, any>;
  },
  periods?: {
    contractPeriod: string;
    cancellationPeriod: string;
  }[],
  quantityDetails: {
    aggregationType: 'count' | 'count_unique' | 'max' | 'sum' | 'average' | 'last_value';
    unit: string;
    description?: string;
    quantityEditable: boolean;
  },
  price: {
    currencyCode: string;
    taxRate?: number;
    totalNetAmount: number;
    type: 'recurring' | 'instant_metered' | 'metered';
    calculationType: 'flat_fee' | 'per_unit' | 'tiered' | 'volume' | 'stair_step' | 'percentage';
    payInAdvance: boolean;
    freeUnits?: number;
    price: {
      amount?: number;
      items?: {
        from: number;
        to?: number;
        amount: number;
        flatAmount: number;
      },
      percentage?: number;
      fixedAmount?: number;
    };
    recurring?: {
      interval: 'day' | 'week' | 'month' | 'year';
      intervalCount?: number;
      trialPeriodDays?: number;
      recurringAmount?: number;
    }
  },
  optionSets: CartPublicItemOptionSet[];
}

export type CartPublicItemOptionSet = {
  label: string;
  name: string;
  options: CartPublicItemOption[];
}

export type CartPublicItemOption = {
  label: string;
  value: string | number | boolean;
  preselected: boolean;
  product?: string | null;
  pricePlan?: string | null;
}

export type CartDiscountDetails = {
  discount: {
    code: string;
    name: string;
    type: 'percentage' | 'fixed_amount';
    percentage?: number;
    fixedAmount?: string;
    frequency: 'once' | 'limited' | 'lifetime';
    frequencyInterval?: number;
  };
  totalAmount: string;
  totalNetBeforeDiscount: string;
};

export type CartPublicPrice = {
  amountDue: number;
  currencyCode: string;
  netAmount?: number;
  taxes?: {
    netAmount: number;
    taxAmount: number;
    rate: number;
  }[];
  discountDetails?: CartDiscountDetails;
}

export type CartPublicSettings = {
  allowCoupons: boolean;
  forceCompany: boolean;
  backButton?: {
    label?: string;
    url: string;
  };
  showDeliveryAddress: boolean;
}

export type CartPublic = {
  id: string;
  customer?: string;
  email?: string;
  invoiceAddress?: CartPublicCustomerAddress;
  deliveryAddress?: CartPublicCustomerAddress;
  items: CartPublicItem[];
  price: CartPublicPrice;
  completionDetails?: {
    invoice: {
      number: string;
      downloadLink: string;
      amount: string;
    } | null,
    payment: {
      reference: string | null;
      method: string;
      bankAccount?: {
        iban: string;
        bic: string;
        bankName: string;
        accountHolder: string;
        reference: string;
      },
      qrCode?: string;
    },
    subscription?: {
      number: string;
    },
    confirmationMessage?: string;
    backToProviderUrl?: string | null;
  },
  settings: CartPublicSettings;
}

Getting Started

Customers

Products

Usage-Based Billing

Subscriptions

Invoices

Payments

Analytics

AI Assistant

Lists & Filters

Settings

Notifications

Accounting

Developers

How does Fynn Functions work?

Runtimes

Functionality in Fynn Functions

Extension Points

Add Shipping Costs

Context Object

Operations

Example

Add Product Options

Context Object

Operations

Example

Register Function

Global Context Objects

​How does Fynn Functions work?

​Runtimes

​Functionality in Fynn Functions

​Extension Points

​Add Shipping Costs

​Context Object

​Operations

​Example

​Add Product Options

​Context Object

​Operations

​Example

​Register Function

​Global Context Objects

How does Fynn Functions work?

Runtimes

Functionality in Fynn Functions

Extension Points

Add Shipping Costs

Context Object

Operations

Example

Add Product Options

Context Object

Operations

Example

Register Function

Global Context Objects