WRONGTYPE error

A command was used on a key that holds a different data type.

Redis returns this error when you run a command on a key that holds a different data type than the command works with. Each key holds one data type, such as a string, a list, or a hash, and each command works with only one of them.

WRONGTYPE Operation against a key holding the wrong kind of value

Some commands word this error differently. JSON commands return Existing key has wrong Redis type. HyperLogLog commands return WRONGTYPE Key is not a valid HyperLogLog string value. for a key that holds a string but not a HyperLogLog.

Example

GET works with strings, so it fails on a key that holds a list:

> RPUSH mylist "a"
(integer) 1
> GET mylist
(error) WRONGTYPE Operation against a key holding the wrong kind of value

How to fix it

Find out what the key holds with TYPE:

> TYPE mylist
list

Then check which of these causes applies:

• You used a command for a different type. Use a command for the key's type instead. For example, use LRANGE to read a list, and HGET to read a field of a hash. See Data types for the commands each type supports.
• Two parts of your app use the same key name for different data. Give each kind of data its own key prefix, such as user: for hashes and queue: for lists.
• The key still holds data from an older version of your app. If you no longer need the old data, delete the key with DEL and write it again.