Generate code without guess

If you need simple one off codes that dont need to have a specific value I would use a simple hash system.

For example creatinge the hash I would use todays data and exact time and hash that. For example MD5 would alway generate a 32 charatcer long code. This can be easily created in PHP and stored in the database.

The app would then just check for this code. The app does not need to know the date time as it just checkst if it exist in the DB.

The problem with this approch is the length of the code. If a user has to enter that manually then 32 char is rather long.

I hope this helps and give syou some ideas.

Yes it is helpful Thanks