Learn how bid extension (anti-sniping) works during online bidding, and what it means for how and when bids are placed.
Bid Extension (also known as Anti-Sniping or Soft Close) automatically extends the online bidding end time when a bid is placed in the final minutes of an auction. This gives all bidders a fair chance to respond before the item closes, rather than allowing a last-second bid to end the auction before others can react.
Organizer Key Points
Bid Extension is configured by event organizers through the following settings:
| Setting | Description |
|---|---|
| Bid extension trigger window | The amount of time, in minutes, before the online bidding end time during which a new bid triggers an extension. |
| Bid extension duration | The amount of time, in minutes, added to the online bidding end time when a bid is placed within the trigger window. |
| Maximum bid extension | The maximum total time, in minutes, that can be added to the original online bidding end time. |
Applies to Online items only
Bid Extension Rules apply only to Online type items.
See Online Bidding Type for more information on item types, and Bid Extension Rules for organizer configuration details.
Bid Extension Rules
Bid Extension Rules are an optional group of settings that allow organizers to ensure all bidders have an opportunity to make their final bid before online bidding ends.
Some bidders use a strategy of placing a bid exceeding the current highest bid as late as possible — often seconds before the end — to prevent other bidders from having time to respond. When Bid Extension Rules are enabled, any bid placed within the trigger window extends the end time, giving other bidders a chance to respond.
Check with your event organizer
If you are unsure whether bid extension is active for your event, check with the organizer. If it is enabled, they may also post this information on the event website.
Bid Extension Rules Example
Using the settings: trigger window = 5 minutes, extension duration = 10 minutes, maximum extension = 30 minutes:
| Bid Time | Bid Amount | Online Bidding End Time |
|---|---|---|
| 9:45 PM | $100 | 10:00 PM |
| 9:54 PM | $120 | 10:00 PM |
| 9:57 PM | $130 | 10:10 PM ¹ |
| 10:03 PM | $140 | 10:10 PM ² |
| 10:09 PM | $150 | 10:20 PM ¹ |
| 10:17 PM | $160 | 10:30 PM ³ |
| 10:29 PM | $175 | 10:30 PM ⁴ |
¹ The bid was placed before the end time and within the 5-minute trigger window — the end time is extended by the bid extension duration (10 minutes).
² The bid was placed before the end time (10:10 PM) but was not within the 5-minute trigger window — no extension is triggered.
³ The bid was placed before the end time (10:20 PM) and within the 5-minute trigger window — the end time is extended to its maximum: the original end time + maximum bid extension (10:30 PM).
⁴ The bid was placed before the end time (10:30 PM) and within the 5-minute trigger window, but the maximum extension has already been reached — no further extension occurs.
Maximum Bidding and Bid Extension
By default, Maximum Bidding (also known as Proxy Bidding) is enabled for auctions. If a maximum bid is made during a Bid Extension window, it is honored — Bid Extension Rules only extend the online bidding time for an item, not the bidding rules themselves.
Maximum bids during a bid extension
If a maximum bid exists for an item and another bidder places a bid within the trigger window, the maximum bid will be used automatically (following Maximum Bidding Rules and using the same bid times), and Bid Extension Rules will continue to trigger as described above.
See Maximum Bidding for details on how maximum bidding works.