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Live Guard High Availability

With Live Guard High Availability, we aim to adjust to any network situation in such a manner that we provide the most possible functionalities at any given moment.

How does it work?

In an ideal world, your devices and applications are always able to reach EVA Cloud.


This will not always be the case though, so Live Guard provides two possible fallbacks;

  1. A very lightweight EVA instance running on your Watchtower device, called EVA Edge. This EVA instance can take over whenever you lose connection to the internet or EVA. When this happens, you move to what we call Local mode.
  2. A Live Guard module in our applications that caches certain information like products and the current order.

You can enable Local mode by setting LiveGuard:Available to true. If it's enabled, then if EVA Cloud is unreachable (either because EVA is down or you have no internet), local mode kicks in. That is, if your local Watchtower device can be reached.

Local mode

While in Local mode, we allow for order creation, assembly and checkout using EVA Pay, PIN (if configured properly), cash and custom payment methods. Products are available, as well as a local order history, albeit in a slimmed-down manner. We also allow for manual discounts and price overrides, markdown prices and PIN logins.


Some additional functionalities remain available when just EVA Cloud is down, but you are still connected to the internet. Because it's just EVA that's down, we can still perform PIN payments through external PSP's. AvaTax will also remain available to perform tax calculations.

Products available in Local mode

To make Watchtower work as efficiently as possible, we don't include all products on it by default. Instead, a product has to meet one of the following requirements in order to be included in the product synch:

  • The product has stock at one of the stores within the country (using the same assortment);
  • the product has recently been sold at one of the stores within the country (using the same assortment);
  • the product is contained within a bundle in the whole assortment;
  • the product is related to one of the matched products by parent/child relationships.

A selection that fits these criteria is prepared and sent to Watchtower every night.

Sharing the same network

In order for Watchtower to be able to find PIN terminals and enable PIN payments in local mode, these devices need to be in the same network.

POS functionalities in Local mode

To make it as clear as possible what you can expect to do in your stores while POS is in Local mode, you can expand the following section for a list of all available functionalities.

POS Local mode functionalities
FunctionalitySupportedNot supportedRemark
PIN login for employeesV
Searching and scanning productsV
Searching for ordersVLocally created orders only - Cloud orders unavailable until connection is restored.
Reprinting of receipts of ordersVLocally created orders only.
Navigation to the Product detail page from the search pagex
Product search suggestionsx
Order details pageV
Attaching customer to orderx
Creating returns (Orders/Order lines)x
Attach shopping cart to orderx
Creating shipmentsx
Shipments listx
Editing wish listsx
Order payments tabV
Order search pageV
Changing line action typexCarry-out only
Opening the cash drawerV
Checkout-related functionalitySupportedNot supportedRemark
Checkout pageV
Basic checkoutVCarry-out only
Anything customer-related in the checkoutx
Checkout optionsVOnly a select few are available
Coupon codesx
Manual discountsVPercentages and amounts only - all the other functions of the discount engine are unavailable.
Payment method: CashV
Payment method: PINVAdyen's offline PIN functionality
Payment method: EVA PayV
Payment method: GiftcardsX
Payment method: Custom payment methodsV
POS Local mode FAQ
  • Why are receipts printed twice?
    • Receipts are printed twice in Local mode to ensure there's always a carbon copy of the receipt in case it ever needs to be recovered. We advise the store to pin this receipt - just like in the old days.
  • Do I need to enable Local mode myself?
    • If configured, the Local mode detection algorithm will continuously check for connection to EVA and the Internet. If either becomes unreachable while the checkout process has started (meaning there's at least 1 product in the basket), the App will enter Local mode and remain in it until the transaction is finished or cleared.
  • What happens when the Cloud is available again?
    • As soon as the Watchtower determines that it's able to reach the Cloud again, it will start pushing all the orders that were made while in Local mode.
      • These orders can be recognized by the "Imported from LiveGuard" filter on the order properties.
  • Who can login?
    • All employees with a role on the organization unit where the Watchtower is boarded will be able to log in.
  • Is the data in Local mode up to date?
    • Watchtower will update the data from the Cloud at least once a day, provided there's an internet connection available.
    • It will also update the data when it's (re)booted - to make sure the data is as up to date as possible
  • What product data can I expect while in Local mode?
    • A small version of the primary image of the products is stored on the Watchtower.
    • Products only have the identifiers, name and properties which are needed for configurable products available.
  • What ports are open to me?
    • Only the following port is available :8080

The following image shows you a POS that's in Local mode along with its limited functionality.


When local mode is activated, a modal will appear in the following scenarios:

  • On unsupported pages on POS, the modal shows up and redirects the employee to the basket.
  • On supported pages on POS, the modal shows up and allows the employee to continue on the current page.
  • When transitioning from Local mode to EVA Cloud and returning back to Local mode, the modal will reappear.

Live Guard local mode

When your applications can't reach EVA Cloud, nor Watchtower, we've got ourselves a little situation.


When we have to fall back to the Live Guard module in the application itself, we just store your current order information so we can pick up where we left off when the connection to either Watchtower or EVA Cloud is restored. In this scenario it remains impossible to process orders. Consider this fallback somewhat of an 'anti stall'.

When is EVA Cloud considered unreachable?

Watchtower pings the internet and EVA Cloud every minute. As soon as a ping fails to generate a response, Watchtower itself will go over to local mode. Additionally POS has its own frequent connection checks, which will determine when it switches over to Local mode in combination with the Watchtower instead of the internet.

This transition from EVA Cloud to your local Watchtower is seamless and invisible to users. The current order is always known on the device, so the user can continue working on the order as if nothing happened.

However, you can only scan products that have been sold by the store in the past 3 months and are currently in stock before going offline. This restriction is in place to avoid the need for a retrieval of the entire catalog of products.


During this local mode, Watchtower logs all events in order to later sync these events when the connection to EVA Cloud is restored.

When entering Watchtower mode, an alert is shown and users are automatically navigated back to the Basket.

Going back online

During local mode, Watchtower keeps pinging EVA and the internet every minute. As soon as the ping returns a response three consecutive times, all devices connect to EVA Cloud again, and Watchtower makes sure to correctly synchronize all offline events towards EVA Cloud.

Forcing local mode

In case your internet is super wonky, but Watchtower manages to ping successfully now and then, local mode will not trigger. In that case, you might want to force local mode. To do so, set the setting LiveGuard:ForceEVACloudUnavailable to true.