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What is String in Redis?

RedisJunior~1 min read
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In Redis, String is the basic, simplest data type, and everything else is built on it. But despite the name, String in Redis isn't just text.

What a Redis String actually is

A Redis String is a sequence of bytes up to 512 megabytes long, which can hold:

  • plain text ("hello"),
  • a number ("42"),
  • JSON, binary data, images, and even compressed files.

Essentially, it's a universal container for a value keyed by name, where the value is just a set of bytes.

What this looks like

An example command:

bash
SET name "Ruslan" GET name

returns:

javascript
"Ruslan"

Typical usage scenarios

  1. Caching strings or JSON:
bash
SET user:123 '{"name":"Anna","age":27}' EX 3600

→ saves the user's data for 1 hour. 2. Counters and increments Redis can treat numeric strings as numbers:

bash
INCR page_views INCRBY likes 5

The value gets converted and stored as a string automatically, but interpreted as a number. 3. Flags, tokens, temporary data

bash
SET auth_token "abc123" EX 600

Important commands for String

CommandPurpose
SET key valuewrites the value
GET keyreads the value
INCR key / DECR keyincrements/decrements a numeric value
APPEND key valueappends data to the end of the string
GETRANGE key start endgets a substring
MSET key1 val1 key2 val2 ...writes several at once
MGET key1 key2 ...reads several at once

An example as a counter

bash
INCR visits GET visits

Result:

javascript
(integer) 1 (integer) 2 (integer) 3

Summary

String in Redis is a universal byte container. It can be:

  • text, a number, JSON, a binary file,
  • and used for caching, temporary flags, counters, tokens, and more.

It's the fundamental type that Redis's other structures (List, Hash, Set, etc.) are built on.

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