# LINSERT

> Insert before or after pivot.

Use `LINSERT` to insert an element immediately before or after another element of a list.

The pivot is matched by value, and only its first occurrence starting from the head is used. The reply is the new length of the list, `0` when the key does not exist, and `-1` when the pivot value was not found, which is how you tell a failed insert from a successful one.

Finding the pivot means scanning the list, so this is a linear operation; on long lists it is worth keeping an index elsewhere or using a sorted set instead.

## Syntax

```redis
LINSERT <key> (BEFORE | AFTER) <pivot> <element>
```

## Arguments

| Argument | Required | Repeatable | Description |
| --- | --- | --- | --- |
| `<key>` | Yes | No | Redis key targeted by the command. |
| `(BEFORE \| AFTER)` | Yes | No | Where to place the new element relative to the pivot: `BEFORE` or `AFTER`. |
| `<pivot>` | Yes | No | Existing element to insert next to. |
| `<element>` | Yes | No | Element to insert. |

## Response

The reply reports the result of the operation. Error replies have the same shape in RESP2 and RESP3 and are surfaced as exceptions by the SDKs below.

| Protocol | Reply |
| --- | --- |
| RESP2 | Integer: the list length after insertion, `-1` if the pivot was not found, `0` if the key does not exist |
| RESP3 | Integer: the list length after insertion, `-1` if the pivot was not found, `0` if the key does not exist |

<Note>
  Client libraries often decode bulk strings, maps, sets, and numeric strings into language-native values. The table describes the Redis wire reply.
</Note>

## Examples

TCP examples use the TLS `REDIS_URL` from the Upstash console. REST examples use `UPSTASH_REDIS_REST_URL` and `UPSTASH_REDIS_REST_TOKEN`.

<AccordionGroup>

<Accordion title="Redis CLI" icon="terminal">

```bash
LINSERT my-key BEFORE pivot element
```

</Accordion>

<Accordion title="@upstash/redis" icon="node-js" iconType="brands">

```ts
import { Redis } from "@upstash/redis";

const redis = Redis.fromEnv();

await redis.rpush("key", "a", "b", "c");
await redis.linsert("key", "before", "b", "x");
```

</Accordion>

<Accordion title="upstash_redis" icon="python" iconType="brands">

```python
from upstash_redis import Redis

redis = Redis.from_env()
result = redis.linsert("my-key", "BEFORE", "pivot", "element")
print(result)
```

</Accordion>

<Accordion title="ioredis" icon="node-js" iconType="brands">

```ts
import Redis from "ioredis";

const redis = new Redis(process.env.REDIS_URL!);
const result = await redis.linsert("my-key", "BEFORE", "pivot", "element");
console.log(result);
```

</Accordion>

<Accordion title="node-redis" icon="node-js" iconType="brands">

```ts
import { createClient } from "redis";

const client = await createClient({ url: process.env.REDIS_URL })
  .on("error", console.error)
  .connect();
const result = await client.lInsert("my-key", "BEFORE", "pivot", "element");
console.log(result);
```

</Accordion>

<Accordion title="redis-py" icon="python" iconType="brands">

```python
import os
import redis

client = redis.from_url(os.environ["REDIS_URL"])
result = client.linsert("my-key", "BEFORE", "pivot", "element")
print(result)
```

</Accordion>

<Accordion title="go-redis" icon="golang" iconType="brands">

```go
package main

import (
    "context"
    "fmt"
    "os"

    "github.com/redis/go-redis/v9"
)

func main() {
    opts, err := redis.ParseURL(os.Getenv("REDIS_URL"))
    if err != nil {
        panic(err)
    }
    client := redis.NewClient(opts)
    result, err := client.LInsertBefore(context.Background(), "my-key", "pivot", "element").Result()
    if err != nil {
        panic(err)
    }
    fmt.Println(result)
}
```

</Accordion>

<Accordion title="jedis" icon="java" iconType="brands">

```java
import java.net.URI;

import redis.clients.jedis.Jedis;

try (Jedis jedis = new Jedis(new URI(System.getenv("REDIS_URL")))) {
  Object result = jedis.linsert("my-key", redis.clients.jedis.args.ListPosition.BEFORE, "pivot", "element");
  System.out.println(result);
}
```

</Accordion>

<Accordion title="redis-rs" icon="rust" iconType="brands">

```rust
use redis::TypedCommands;

fn main() -> redis::RedisResult<()> {
    let url = std::env::var("REDIS_URL").expect("REDIS_URL is not set");
    let client = redis::Client::open(url)?;
    let mut connection = client.get_connection()?;

    let result = connection.linsert_before("my-key", "pivot", "element")?;
    println!("{result:?}");
    Ok(())
}
```

</Accordion>

</AccordionGroup>