Trading is a system that lets players exchange items with other players. Introduced with the Mann-Conomy Update, this system allows players to swap or gift weapons, cosmetics, tools and more with other players. Valve later implemented the trading feature Steam-wide to encompass other games as well as within Steam itself.
Steam Trading is a feature that was introduced on August 9, 2011 as an open beta. The beta updates were added to the public Steam client on September 6, 2011. With Steam trading, players are able to trade their in-game items for other in-game items and/or gift copies of Steam games. Trade requests can be sent through Steam chat windows or via the Steam Friends List window. Trading will also be disabled for Free to Play (Nothing bought from Mann Co. Store) players.
When trading items with other parties and only Steam Guard is enabled, the trade may be placed on hold for up to 15 days.  If trading with a user who is on the player's Friends list, the trade will be placed on hold for 3 days instead of 15; if the users have been friends for over 1 year, the hold will last 1 day instead.
If Steam Guard Mobile Authenticator has been enabled for both parties for at least 7 days, trades will happen instantly once both sides have confirmed the trade, regardless of friends status.
- At first, the Steam Trading window only shows 8 slots to trade. When the 3rd slot on the last line is filled, more slots will appear. This allows for up to 256 items to be traded at once, eliminating the need for excessive trading.
- Items can also be searched for by using the search bar, making trades quicker and easier to conduct. A chat box is also available and items are color-coded according to their quality.
- Once a trade has been made, any received items are placed into the user's in-game Backpack and Steam Inventory, ready to be used.
- Items from other games can also be traded by clicking the inventory drop down menu and choosing a supported game's inventory.
- On September 4, 2013 a new feature named "Trade Offers" was released. It allows you to send a pre-packaged trade to a friend, similar to regular trading, except you propose the items for both sides. This feature includes the ability for regular traders to generate their own personal trade offer links, allowing other users to send them trade offers without needing to add them as a friend first.
Trading inside Team Fortress 2
In addition to sending trades through Steam, it is possible to send a trade to another player in Team Fortress 2, though it still uses the Steam trading system to do so. The option for this is in the Customize items section of the main menu, accessible through the "Items" button on the main menu, through the key set to open the menu (Default bind: ), or through the console command
This will open a small window with options to select a trading partner from the friends list, the current server, or directly through their Steam profile. If the friends list option is selected, it will show a list of users on the friends list currently playing Team Fortress 2. The current server option will show a list of users in the current server. Once a user is selected through any of the three options, a trade request will be sent to them, which they can choose to accept or deny.
Once a trading partner has been selected, the Steam Overlay will open with a Steam Trade window, which can be toggled to return to the game and vice versa. If the trade is accepted, any items received will be shown in the in-game chat box, if the player is currently in a server.
It is possible to filter the trade requests received through the game's Advanced Options menu. This option can be set to Anyone, Friends Only, Friends and In-Game Players and No-one
Additionally, Free to Play players are not able to trade any items to players, however they may trade items that they have received from another player.
All items in the game are tradable with the exception of items with a "Not Usable in Trading" suffix or an achievement milestone weapon. If metal is crafted using any achievement weapon, it becomes untradable. Anything crafted using untradable items also becomes untradable.
- With the Manniversary Update, all items purchased from the Mann Co. Store will become tradable after two days, as long as the Steam account has made another purchase at least 30 days prior.
- Additionally, items that are awarded in Genuine quality upon pre-ordering a game on Steam are initially untradable, but generally become tradable once the associated game is released or the promotion period ends.
- Items purchased from the Steam Community Marketplace are automatically placed in the user's inventory and can be traded or put back on the market after 7 days.
- If a player is kicked from a server while waiting for a trade request, the timer at the home screen will show over 10,000 seconds.
- Sometimes users in a trade will be unable to add items to a trade or click the 'confirm trade' button. This can typically be fixed by pressing the 'F5' on your keyboard to refresh the trade.
- Often items in a trade will not display correctly for a short period of time after they are added. The picture is typically absent in this scenario along with the item's description and name.
- Sometimes when a user adds an item into the trade, it will not be visible from the other user's perspective, even though the name of the item will be shown in the trade chat. This can be fixed if the other user puts an item into the trade and then takes it out again.
- If you have been scammed, you can file a Steam support ticket and explain the situation. It helps to provide evidence of the scam, such as conversation logs or screenshots/videos of the scammed transaction.
- There is a 30 second waiting period between unsuccessful trade requests.
- If a player sends multiple trade requests to another player who declines them, there is a 2 minute waiting period between each trading request to prevent spamming.
- As of December 12th, 2012, Steam Guard is required for trading items. Steam Guard is required to be on for at least 15 days before trading.
- When a user changes their account password or associated e-mail address, the user is then unable to trade for 5 days. This was implemented to prevent or discourage hijackers stealing others' accounts or items by forcing them to wait.
- You can not trade if your Steam account has been restricted and/or you have been trade banned on Steam.
- As of December 9th, 2015, the Steam Guard Mobile Authenticator is required to be enabled for at least 7 days in order complete a trade without being held for 15 days.
Old Trading System
- Steam Trading: Out of Beta and available to everyone! - TF2 Team
- Steam Trade Holds - Documentation - Knowledge Base - Steam Support