Connect ShipStation to Tatheon and shipping stops being an assumption in your margin calculation and becomes a real cost attached to a real order. This guide is for whoever administers ShipStation. It covers the connection, what it changes about profit reporting, and why an estimated shipping rate is usually wrong in a way that matters.
Why this changes your margin
Without ShipStation, Tatheon costs shipping using a rate you set, applied to every order. That is a reasonable starting assumption and it is wrong at both ends of the distribution.
A single item order posted locally costs far less than the average. A heavy multi item order sent interstate costs far more, and often more than the shipping the customer paid. Averaging hides both. You end up believing your small orders are less profitable than they are and your large ones more, which is precisely backwards when you are deciding what to promote.
With ShipStation connected, each order carries the label cost that was actually paid for it. The profit figure per order becomes real, and the Profit Radar can identify orders that lost money on fulfilment rather than estimating that they might have.
Before you start
You need a ShipStation API key and API secret, created under Settings, then Account, then API Settings.
Generate a key rather than reusing an existing one, for the same reason as any other integration. It can be revoked independently later.
Connect it
Open the source wizard and choose ShipStation. Enter the API key. Tatheon stores it in the secret provider rather than in a configuration file, registers the source account, and then runs its workers to pull labels and shipments.
Backfill runs in bounded chunks like every other source. Shipping history takes several runs to complete for a store with volume, and the board fills in as it goes.
What arrives
Shipments and labels, with the cost paid for each. Tatheon joins these back to the Shopify order so that the cost lands against the order that caused it rather than against the day the label was bought.
That join is the part that matters. Shipping cost reported by day tells you what you spent. Shipping cost reported by order tells you which products, channels and customer segments are expensive to serve, which is the version you can act on.
Confirm it is working
Pick a recent week and compare total label spend in Tatheon against the same week in ShipStation. These should be close.
Then look at a single large order you remember and check that its shipping cost looks like the label you actually bought. Order level accuracy is the reason for connecting this at all, so it is worth verifying at order level rather than only in aggregate.
Common problems
Shipments arriving with no cost usually means labels were purchased outside ShipStation, through a carrier portal directly. Tatheon can only see what ShipStation recorded.
Orders showing no shipping cost at all are often orders that shipped before the backfill reached them. Give it time before treating it as a gap.
Multi package shipments are worth knowing about. One order that ships in two boxes carries two labels, and Tatheon sums them against the single order rather than splitting the order, so the cost stays attached to the thing that caused it.
Next
With real fulfilment costs in place, the profit engine is working from actuals rather than assumptions, and the Profit Radar can flag orders that cost more to serve than they earned.