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Introduction to integrations in Flex

Flex allows integrations with a vast range of third party tools and solutions. These tools can be integrated with Flex by using Zapier, the Flex Integration API, or the client application.

Table of Contents

Integrations in Flex refer to third-party solutions and tools that communicate with the Flex marketplace to either retrieve information and take action outside Flex, or trigger actions within Flex. A lot of features that are not natively available in Flex can be integrated with your marketplace solution with varying degrees of complexity.

Flex integration tools

There are several ways to approach integrating third party tools with your Flex marketplace. Your integration options within Flex depend on the requirements of the third party tool you are integrating, and on the complexity of the integration you are looking to create.

Client application

The simplest integration tool is your client application. Since you have full control over your marketplace client app, you can add analytics and tracking tools such as Hotjar or Goole Analytics, or messaging tools such as Sendbird or Intercom, directly into your client app code.

The FTW templates include a Node.js/Express server by default. Some third party integrations may require a secure context, such as Voucherify or other promotion integrations. For these types of integrations, you can use the FTW server to create endpoints or other logic in a secure way.

Integration API

If you want to create an integration where the third party solution listens to – or takes action on – your Flex marketplace, you will likely need to use the Integration API. Where the Marketplace API is meant for everyday marketplace interactions, the Integration API gives operators powerful access to all marketplace data and activity. Through the Integration API, operators can enable third party tools to manage users, listings, transactions, bookings, stock reservations, and more.

Due to its powerful nature, the Integration API should only ever be used from a secure context, such as your client application server or a separate backend application. Here, too, the FTW server is an excellent place to build your Integration API logic without revealing sensitive information to the public web in your browser client code.


In addition to direct endpoints to marketplace resources, Integration API also exposes events. The majority of activity on your marketplace triggers events – users and listings created and updated, transactions transitioned, and so forth. You can review the full list of supported event types.

By listening to events, you can build flows where third party solutions take action either in Flex or within the solutions themselves. You can read more about reacting to events in Flex.


Sharetribe has also built a Zapier integration to facilitate integrating third-party tools with Flex. The Zapier integration works by harnessing a subset of Flex events and allowing operators to connect any of the other 5000+ tools and solutions in the Zapier ecosystem.

The Flex Zapier integration makes it easier to take action in your favorite business tools, such as Hubspot, MailChimp and others, based on your Flex marketplace activity. However, Zapier cannot currently perform operations within Flex. In other words, if you need to take action in Flex based on activity in other solutions, you will need to use the Integration API directly.

Levels of integration

The complexity of a Flex integration with a third party tool can range from very simple to highly complex. One aspect determining the complexity is how intertwined the two tools need to be. On the simple end, adding a script to the client application for a tracking tool is a trivial change, and on the complex end a full third party payment gateway integration will likely take several weeks to implement.

The full complexity of the feature also depends on the different use cases you need to cover on each side of the integration. For instance, if you want to integrate your Flex marketplace with Shopify and synchronize listing stock between the two platforms, you will need to cover several use cases on both sides, such as adding, updating and removing listings, as well as handling purchases, returns and disputes.

For illustration, here are some examples of types of integrations with different levels of complexity:

Simple integrations:

  • Calling third party APIs and SDKs from your client application

    • use cases: uploading files to external storage, adding a messaging tool
  • Adding a third-party script to your client application

    • use cases: integrating analytics providers
  • Adding a custom endpoint in your client app server that calls a third party API and then updates information in Flex using the Marketplace API or the Integration API

    • use cases: enabling downloadable content in listings
  • Listening to Flex events using Zapier and taking action in another Zapier-connected application

    • use cases: sending a text message of a new booking to providers using Twilio

More complex integrations

  • Listening to Flex events using your own polling tool and taking action within Flex

    • use cases: partial or complete payment gateway integrations
  • Synchronizing Flex and a parallel system to update each other when any changes happen in either solution

    • use cases: calendar integration, Shopify

Examples of specific integrations

Hotjar analytics

Hotjar is an analytics tool for websites that allows you to collect user activity heatmaps, feedback, and user behavior recordings, among other features.

Mailchimp email list

Mailchimp is an email marketing and automations tool that you can use to communicate directly with your marketplace users. Since Mailchimp uses Zapier, integrating Flex and Mailchimp is straightforward:

Twilio SMS

Twilio is a communications platform that offers multiple channels of communicating with your marketplace users, including SMS and WhatsApp messages, calls and video. Twilio has a Zapier integration, so you can use Zapier to trigger actions in Twilio tools with no coding.

  • Follow the Flex video guide to send providers a SMS message whenever their listing gets booked.

Sendbird user-to-user chat app

In Flex, messages between users are always related to transactions. If you want to allow more complex messaging flows between users, you can integrate a user-to-user chat tool such as Sendbird. The initial integration is fairly straightforward to implement, and the eventual complexity depends on the use cases you want to cover.

  • Create an account in Sendbird.
  • Add the Sendbird UI kit and SDK.
  • Implement and stylise a UI chat component.
  • Initialise a Sendbird user id for the user when they sign up to Flex, and save it in the user's private data so it can be used whenever they log in.

Voucherify discount coupons

Voucherify is a promotions tool that allows you to create, validate and redeem discount coupons, gift cards, automatic discounts and other promotional offers. The initial integration has a number of steps but is still fairly straightforward to implement, and the eventual complexity depends on the use cases you want to cover.

  • Create an account in Voucherify and create your own codes or use the sample codes.
  • Add Voucherify SDK.
  • Create a helper file in the server that contains functions to validate and redeem a code using the Voucherify SDK.
  • Add an input element to the order panel for the discount code.
  • Pass the discount code to the line item calculation and to CheckoutPage (in a similar way to this pricing tutorial).
  • Validate the code in endpoints for transaction-line-items, initiate-privileged and transition-privileged, and pass the validation result to server/api-util/lineItems.js.
  • Add a logic to server/api-util/lineItems.js that adds a discount line item with the correct percentage or amount if the code is valid. You will need to decide whether the discount line item is included
    • for both customer and provider, in which case the provider receives a decreased payout,
    • or only for the customer, in which case the marketplace receives a decreased commission – in this case, the discount cannot be greater than the marketplace commission.
  • Only redeem the code once i.e. when actually initiating or transitioning the transaction with Marketplace API.

Google Calendar synchronised with Flex availability calendar

If you run a booking marketplace, you may want to allow providers to synchronize their own Google Calendar to their listing's Flex availability calendar. That way, providers do not need to add availability exceptions manually to Flex, and they will be able to see any bookings in their own calendar without needing to visit the marketplace. Like all two-way integrations, this is a complex one, and you will need to specify the use cases you want to cover to determine the full complexity of the integration.

  • Google provides Calendar API to modify calendar events.
  • You can set up push notifications to track changes on the Google side.
  • Authenticate your Flex app to get information and make changes on behalf of the user in Google Calendar.
  • Whenever a booking gets created or updated in Flex, update the provider's Google Calendar accordingly. You can do this either by
    • creating custom endpoints in your client app server that call the Flex APIs as well as the Calendar APIs,
    • or you can listen to Flex events and call the Calendar APIs on relevant events.
  • You can watch the provider's Google Calendar, and whenever a new event is created or an existing one is removed, create or remove an availability exception in Flex to prevent other customers from booking that specific time slot.

Payment gateway integration

Integrating a third-party payment gateway, such as Paypal Commerce Platform or Stripe Billing, is a complex and extensive integration. Even when you follow our high-level guide on integrating a payment gateway, you will need to do a lot of your own investigating and testing, as well as collaborate closely with the support team of the payment gateway provider you have chosen.

  • Contact the support team of the payment gateway tool you intend to use, and make sure you are eligible for their service. Some providers may have limitations regarding platform size or geography.
  • Get familiar with our how-to article on integrating a third-party payment gateway to Flex.