question How to check backorders for a domain in pending delete state

If you think about your question for a second you'll realise that what you ask is nearly impossible.

A backorder can be made by any registrar and/or backorder service anywhere in the world.
You are asking for a way to check every possible entity that can run a backorder anywhere in the world if they have a specific domain in their list to backorder.

Ok... That means it is impossible. But, I checked a post where a comment said "I have checked there is no backorder on domain." Thats why I asked. Anyways thanks for the update.

You may be able to check a backorder at some specific backorder service that provides that detail.

Also, besides backorder services, people also use drop catching softwares. So, if you are looking to handreg a dropping name, you can imagine noone backordered it and noone even used a software. As no way one can beat these while trying to handreg a dropping name.

be careful with searching backorder/dropcatching sites for the name you want to handreg/catch. Doing so could trigger them to catch the name because they see there is interest.

There are backordering services that will always tell you, tell you sometimes, and never tell you. NameJet will only tell you if at least 3 people have backordered it.

The best way to do this is to determine what the domain name is worth to you and then only spend that. If it's worth $8 to you, then don't backorder it. Hand-register it if possible. If it's worth $15-20 to you, then backorder it at one of the less expensive sites like GoDaddy or Dynadot. And so on and so forth at companies like DropCatch, NameJet, and Snapnames, the more expensive options.

You'll find that unless the domain name is really good, no one else is backordering it.