Related

Set Key Value

redis

Set a string value for a given key in Redis.

Get Key Value

redis

Retrieve the string value stored at a key.

Get Hash Field

redis

Retrieve the value of a specific field from a hash.

redis/incr

Increment Value

Increment the integer value of a key by one.

redis
string
counter
numeric

Command

INCR key

Explanation

The INCR command is atomic — meaning it can safely be used in concurrent environments without race conditions. It’s useful for implementing counters, rate limiters, or metrics. If the key holds a non-integer value, Redis returns an error.

Common Use Cases

  • •Counting page views or API requests
  • •Implementing rate limiting
  • •Tracking event occurrences

Best Practices

  • ✓Use namespaced keys like `metrics:visits` for clarity
  • ✓Use `INCRBY` for larger increments to reduce command count
  • ✓Persist counters periodically if durability is required

Common Mistakes to Avoid

  • ⚠Using INCR on keys with non-integer values
  • ⚠Forgetting Redis stores all data as strings

Troubleshooting

Problem: ERR value is not an integer

Solution: Delete or reset the key if it contains non-numeric data (`DEL key`).

Problem: Counter resets unexpectedly

Solution: Check for overwriting with `SET` or `FLUSHALL` commands.

Examples

Increment 'counter' by 1

INCR counter

Track user login count

INCR user:100:logins

More

Set Hash Field

redis

Set a specific field in a hash to a given value.

Get All Hash Fields

redis

Retrieve all fields and their values from a hash.

List Push Left

redis

Prepend to list