Direct Swaps are one of the most popular ways to exchange postcards on Cardzilla. They are designed for a simple situation: you have a particular postcard available now, another user has a particular postcard available now, and you want to exchange them.
But not every exchange works this way.
What if you have several identical postcards? What if you already know which postcards you will get at an upcoming meetup, festival, or trip, but you do not have them yet? Or what if you are going to visit another country and want to arrange exchanges in advance, because you may not have time to negotiate while you are there?
Swap Listings are designed for these situations!
A Swap Listing is an announcement that you expect to have a certain number of identical postcards available in the future. The listing specifies what the postcards will look like, how many you expect to have, where you will send them from, and when you expect to be ready to send them.
This allows you to arrange exchanges in advance, while keeping the actual exchange conditional on the announced event happening and the postcards becoming available.
There is an important difference between a Swap Listing and a regular direct-swap offer.
A direct-swap offer represents one particular postcard that is already available. Once a direct swap is confirmed, that postcard is used in the exchange and is removed from the available offers.
A Swap Listing represents a future supply of several identical postcards. The postcards do not have to be available yet. Instead, the listing reserves a number of future exchange opportunities.
For example, you might create a listing for:
10 postcards from a postcard meetup in Guatemala City, to be sent from Guatemala after October 3.
You can then receive requests from other users before October 3. You can decide which requests you want to accept, even though the actual postcards do not exist in your collection yet.
To make the process easier to understand, this article uses two terms:
The listing owner decides which requesters they want to exchange with.
Before creating a listing, the listing owner should know:
These details are fixed when the listing is created.
The listing must specify how many identical postcards are expected to be available.
For example, if you expect to have 15 copies of a particular postcard, the listing can accept up to 15 confirmed exchanges.
Cardzilla keeps track of the number of postcards that have already been reserved through approved requests and prevents the listing owner from accepting more requests than the number of postcards announced in the listing.
If a request is later cancelled, its reservation is released and the listing owner can accept another request.
The listing must specify the country from which the postcards will be sent.
This is useful when the postcards are connected to a trip, meetup, event, or another specific location.
For example:
Sending country: Japan
The listing owner is expected to send the postcards from the country specified in the listing.
The listing must also specify a sending date.
This is an important part of the listing because the exchanges cannot be completed before this date.
The date is the point at which the listing owner is expected to know whether the announced event actually happened and whether the postcards are available and ready to be sent.
If the listing owner does not confirm that everything is ready when the sending date arrives, the pending requests associated with the listing will eventually be cancelled automatically.
The front-side image of the postcard is required.
You can also add an image of the back side if it is useful.
The image should give requesters a good idea of what they will receive. Since the postcards are expected to be identical, the image represents the postcards described by the listing.
A detailed description is strongly recommended.
You can explain:
For example, a listing might describe postcards that will be obtained at a particular meetup, from a museum, during a trip, or at a special event.
The more information you provide, the easier it is for other users to understand what they are requesting.
All registered Cardzilla users can browse Swap Listings and send a request to a listing.
A requester chooses a listing they are interested in and specifies what they are willing to send in return.
As with direct swaps, the requester can offer:
After the request is submitted, a Swap Request is created with the status Pending.
At this point, the requester has proposed an exchange, but the listing owner has not yet agreed to it.
The listing owner can review incoming Swap Requests and decide which ones they want to accept.
For each request, the listing owner can see what the requester is offering and can select the particular postcard they want to receive.
The listing owner then has three possible choices:
When a request is approved, its status becomes Approved.
The selected postcard is now reserved for this potential exchange, and one of the postcards in the listing is also reserved.
Swap Listings do not work on a first-come, first-served basis.
The listing owner chooses which requesters they want to exchange with. There is no requirement to approve requests in the order in which they were received.
For example, if a listing has five postcards available and receives ten requests, the listing owner can choose any five of those requests.
The listing owner can also change their mind.
Even after approving a request, the listing owner can cancel it before the actual swap is created. When a request is cancelled, its reserved postcard becomes available again, and the listing owner can approve another request.
Before the sending date, a Swap Request cannot progress beyond Approved.
This is intentional.
At this stage, the exchange has been agreed in principle, but the actual postcards described by the listing may not exist yet. The listing owner may still be waiting for the announced event, trip, meetup, or other circumstance that will make the postcards available.
Cardzilla keeps track of the reservations so that the number of approved requests never exceeds the number of postcards announced in the listing.
For example, if a listing contains 10 postcards, there can be no more than 10 active approved requests at the same time.
When the sending date arrives, the listing owner can confirm that the expected event has happened and that the postcards are actually available.
If everything is ready, the listing owner can send a special notification to all users whose requests have been approved.
This notification means:
The event happened, I have the postcards, and I am at the announced location and ready to send them.
When this notification is sent, the status of the approved requests changes to Ping Sent.
The Ping Sent stage is the final confirmation step before the normal postcard exchange begins.
After receiving the notification, the requester has 24 hours to check that they still have the postcard they originally offered.
This is important because the request may have been made days or weeks earlier. The offered postcard might have been sent to someone else, exchanged, or otherwise become unavailable in the meantime.
The requester must therefore check their collection and confirm that the selected postcard is still available.
The requester confirms the exchange.
The Swap Request is then converted into a normal Swap Contract.
At this point, the exchange proceeds like an ordinary direct swap:
The future arrangement has now become an actual postcard exchange.
The requester should not confirm the exchange if they no longer have the postcard they offered.
The request will be cancelled, the reservation will be released, and the listing owner can choose another requester instead.
The Ping Sent stage has a 24-hour response period.
If the requester does not confirm the exchange within that time, the request is automatically cancelled.
Again, the reservation is released, allowing the listing owner to accept another request.
It is also possible for the listing owner to approve a request only after the sending date has already arrived.
In that situation, there is no reason to wait for another date.
The listing owner has already reached the point where the postcards are expected to be available, so a newly approved request immediately enters the Ping Sent stage instead of going through Approved first.
The requester then has the same 24-hour period to check their offered postcard and confirm the exchange.
A Swap Listing is based on a future event or situation that is expected to make the postcards available. That event may sometimes fail to happen.
For example:
If the listing owner cannot confirm that the postcards are available and ready to send, the approved requests associated with the listing will be automatically cancelled.
This is one of the main differences from a normal direct swap: a Swap Listing is an arrangement for a future exchange, not a guarantee that a particular physical postcard is already in the owner's possession.
Imagine that you are going to a postcard meetup in Spain.
You expect to receive 20 identical postcards that were specially made for the event. You will be able to send them from Spain on October 15.
You create a Swap Listing with:
Over the following weeks, other users discover your listing and send Swap Requests.
Suppose you receive 35 requests.
You can review all 35 and choose the 20 requesters you would like to exchange with. You select the postcards they are offering and approve those requests.
The 20 approved requests reserve all 20 postcards in the listing.
The remaining 15 requests do not reserve anything.
On October 15, the meetup has taken place, you have the postcards, and you are in Spain.
You send the Ping Sent notification.
Each of the 20 requesters now has 24 hours to check whether they still have the postcard they originally offered.
If 18 people confirm and 2 people cannot complete the exchange, those 2 requests are cancelled and their two reservations are released. You can then choose two other suitable requests, if any are still available.
The confirmed exchanges become normal Swap Contracts and proceed through the regular sending process.
Swap Listings are useful whenever a normal direct swap does not fit the situation.
For example, they can be used when:
The key idea is simple:
A direct swap is an exchange of postcards that are available now. A Swap Listing is an opportunity to arrange exchanges for postcards that are expected to become available in the future.
This gives both sides more flexibility while keeping the final exchange within Cardzilla's normal Swap Contract system.