Founder packs

What you will do

A founder pack is an ordinary pack with three extras: a sale window, a total stock, and a founder flag. You use it to sell before your game launches ("the first 500 players get a golden sword"), or to run a limited offer.

When a player buys one, the coins and items are delivered right away to the wallet of the player. There is no "pending" currency: the game reads the wallet when it launches, like any other balance. To let a player in a game without a backend keep that wallet, ask for an e-mail first: see Sign in with e-mail.

The three options are independent. A pack can have only a window, only a stock, or only the flag. A pack with none of them is always on sale, without limit, as before.

Set up a founder pack

In the dashboard (in French for now), open your game, then « Packs »:

1. Create or edit a pack. Open the section « Disponibilité et pack fondateur ».
2. Tick « Pack fondateur » to show the founder badge and a public counter.
3. Fill « Début de la vente » and « Fin de la vente » to set the window, and « Stock total » to limit the quantity. Leave a field empty for no limit. Dates are in Paris time.
4. Publish the pack. Each pack in the list shows its state (« Programmé », « En vente », « Épuisé », « Terminé »), the founder badge and the counter « vendus sur stock ».

To announce the launch, open « Réglages » and fill the section « Lancement »: tick « Le jeu n'est pas encore lancé (précommande) » and give the launch date. A shop then shows pre-orders, and the receipts mention the date.

Rules to know:

• The window starts at startsAt (included) and ends at endsAt (excluded).
• The total stock cannot be set below the number of units already sold.
• The sold counter of the dashboard counts the live environment.

Read the availability

The catalog carries it, for the server and for the browser:

curl "https://gamecoin.apilow.com/api/v1/client/catalog" \
  -H "X-GameCoin-Key: $GAMECOIN_PUBLISHABLE_KEY"

{
  "sku": "founder-pack",
  "name": "Founder pack",
  "priceCents": 1999,
  "maxPerPlayer": 1,
  "availability": {
    "startsAt": "2026-10-01T00:00:00.000Z",
    "endsAt": "2026-12-01T00:00:00.000Z",
    "remaining": 312,
    "founder": true
  }
}

The answer also has prelaunch and launchAt for the whole game.

• remaining is the number of units that can still be bought, or null for an unlimited stock. Use it for the public counter: "312 left".
• The catalog also lists packs that are scheduled, ended or sold out. Show them as "coming soon", "ended" or "sold out" instead of hiding them. Compare startsAt and endsAt with the clock of the player.
• A pack that is not limited has availability: null.

What happens when a player buys

An order for a limited pack holds one unit of the stock from the moment it is created. That is how GameCoin never sells more than the stock, even when thousands of players click at the same time.

So remaining can go up again: when a pending order expires, or when you refund a sale. A second request by the same player for the same pack returns the order that is already pending and holds nothing more.

The window is checked when the order is created. A player who started before the end can still pay after it, within the hour.

Errors

A checkout for a pack that cannot be sold answers 409:

{ "error": { "code": "PACK_NOT_AVAILABLE", "message": "The pack is not on sale", "details": { "startsAt": "2026-11-01T09:00:00.000Z", "endsAt": null } } }

See Errors for the full list.

Test it

The test and live environments have separate stocks: a purchase made with a test key never uses a unit of the live stock. In the test environment you can run out of stock, wait for the orders to expire, and try the refunds, with simulated payments. See Testing.

Where next

• Selling packs: checkouts, VAT and the life of an order.
• PackAvailability: the object in detail.
• Refunds: give a unit back to the stock.