Marketplace — server-wide trading board for Valheim

A trading board for every player on the server. Anyone can list any item from their inventory at their own price, and others can buy it — even while the seller is offline. The currency is regular Valheim coins, and every player gets a server-side bank for storing them safely.

How to use

Press F7 (configurable) to open the marketplace. Esc or F7 closes it.

Tab	What it does
BUY	All listings on the server, with search (item or seller name) and sorting. Pick a listing, set the amount (- / + / Max) and click Buy.
SELL	Items from your inventory. Pick one, set the amount and price per piece, click List for sale. The item leaves your inventory and waits for a buyer.
ORDERS	The order board — buy orders and bounties (see below).
MY LISTINGS	Your active listings. Cancel any of them to get the item back.
MAILBOX	Items from cancelled or expired listings. Collect all moves them to your inventory.
BANK	Your coin balance and transaction history. Deposit / Withdraw a chosen amount, or everything at once.

• Sale income goes straight to your bank balance. If you are online, you get a notification.
• Purchases are paid from your balance first; if it is too low, the rest is taken from coins in your inventory.
• Bought items go straight to your inventory. If it is full, the rest is dropped next to you.
• You can buy part of a stack (e.g. 20 out of 100 wood).
• Quality, variant, durability, crafter and other mods' item data (m_customData) are preserved.
• Equipped items and coins cannot be listed.

Order board

The marketplace the other way round: players post what they need, and the coins are locked on the server the moment the order is posted, so the other side knows the money is there.

Buy orders

"Buying 50× Black Metal at 40 coins each."

1. + Buy order → search for the item, set the amount and price per piece → Post buy order. The full amount (here 2000 coins) is taken from your bank balance (the shortfall from your inventory) and locked in the order.
2. Anyone who has the item opens the order, sets how many pieces to deliver and clicks Sell. They get paid immediately, and the items go to the buyer's MAILBOX. Partial deliveries are fine.
3. The buyer can cancel at any time — the coins still locked in the order go back to their balance. Expired orders (ExpireHours) are refunded the same way.

Any quality of the item is accepted.

Bounties

"Build a bridge over the river near spawn — 500 coins."

1. + Bounty → title, description, reward → Post bounty. The reward is locked on the server.
2. A contractor clicks Take this job. From now on nobody else can take it.
3. When the work is done, the contractor clicks Report as done.
4. The poster checks the work and clicks Confirm & pay (the reward goes to the contractor's balance) or Reject (the contractor continues and reports again).

Who	Can
Poster	Cancel while nobody has taken the job. Confirm (pay) at any point after it has been taken. Reject a report. Cancel a taken job if the contractor has not reported it as done within BountyClaimTimeoutHours.
Contractor	Report as done. Abandon the job (it becomes open again).
Server admin	Pay out or cancel any taken bounty and cancel any buy order — for resolving disputes.

Open bounties nobody takes expire after ExpireHours and are refunded. The tab label shows how many reports wait for your confirmation, e.g. ORDERS (1).

Installation

The mod must be installed on the server and on every client. Jotunn rejects players without it.

Requirements: BepInExPack_Valheim, Jotunn 2.29.0 or newer.

1. Copy the Northarun-Marketplace folder to BepInEx/plugins/. In r2modman: profile → Browse profile folder → BepInEx/plugins.
2. On a dedicated server, copy the same folder to the server's BepInEx/plugins/.
3. Start the server once — the config file BepInEx/config/adrian.valheim.marketplace.cfg is created.

Configuration

Section	Setting	Default	Description
1 - Client	Hotkey	F7	Key that opens the window.
1 - Client	Language	English	English or Polish. Can be changed in game (e.g. with Configuration Manager).
2 - Server	FeePercent	0	Percentage deducted from every payout (sales, deliveries to buy orders, bounty rewards), 0–50. The fee removes coins from the economy.
2 - Server	MaxListingsPerPlayer	25	Simultaneous listings per player.
2 - Server	ExpireHours	168	Real-time hours until a listing returns to the seller's mailbox. 0 = never.
2 - Server	MaxPricePerUnit	100000	Highest allowed price per piece.
2 - Server	BlockedItems	(empty)	Comma-separated prefab names that cannot be listed or requested in buy orders, e.g. DragonEgg,Wishbone.
3 - Order Board	MaxBuyOrdersPerPlayer	10	Simultaneous buy orders per player.
3 - Order Board	MaxBountiesPerPlayer	10	Simultaneous bounties per player.
3 - Order Board	BountyClaimTimeoutHours	72	If a contractor does not report a taken job as done within this time, the poster may cancel it and get the reward back. 0 = only admins can cancel taken bounties.

Server settings are taken from the server's config file; clients receive them together with the listings.

Data and security

• The server keeps listings, buy orders, bounties, mailboxes and bank balances in BepInEx/config/Marketplace/<world name>.dat. It saves after every change and keeps the previous version as .dat.bak. Each world has its own marketplace.
• Every operation is appended to BepInEx/config/Marketplace/<world name>.log: listing, purchase, cancellation, expiry, deposit, withdrawal, buy orders and their deliveries, every bounty step (take, report, confirm, reject, cancel), with the balance after the operation. Use it to settle bounty disputes.
• Coins locked in buy orders and bounties never leave the server: they are either in an order or on someone's balance.
• Only the server changes balances. A withdrawal is checked against the server balance before any coins are sent.
• Players are identified by the character ID from their in-world object, not by what the client claims.
• Every rejected operation returns the item or coins.
• As everywhere in Valheim, the inventory belongs to the client. A modified client could fake a deposit or a listed item, so an anti-cheat (e.g. AzuAntiCheat) is recommended.

Building from source

Windows with .NET Framework 4 is enough (the csc.exe compiler ships with the system):

powershell -ExecutionPolicy Bypass -File build.ps1

Languages

The window is in English by default. Polish is also included: set Language = Polish in BepInEx/config/adrian.valheim.marketplace.cfg. Each player picks their own language; server messages are translated on the client side.