XADD - Upstash Documentation

Use XADD to append an entry to a stream, creating the stream when it does not exist.

An entry is a set of field and value pairs identified by an ID of the form <milliseconds>-<sequence>. Passing * lets the server build the ID from the current time, which guarantees that IDs only ever increase; an explicit ID must be greater than the last one in the stream. The reply is the ID the entry was stored under. NOMKSTREAM skips creating a stream that does not exist yet and returns null instead.

The trimming options cap the stream in the same call, which is how a stream is kept from growing without bound. MAXLEN limits the number of entries and MINID drops entries with an ID below a threshold, which is the way to trim by age since IDs start with a timestamp. ~ makes the trim approximate, stopping at a convenient boundary, which is much cheaper than the exact = and is what most workloads should use; LIMIT caps how many entries a single call may evict.

KEEPREF, DELREF, and ACKED decide what happens to consumer group references of the entries that trimming removes: KEEPREF, the default, leaves those references in place, DELREF removes them as well, and ACKED only removes entries that every group has read and acknowledged.

Syntax#

XADD <key>  [NOMKSTREAM]  [KEEPREF | DELREF | ACKED]  [(MAXLEN | MINID) [= | ~] <threshold> [LIMIT <count>]]  (* | <id>) <field> <value> [<field> <value> ...]

Arguments#

Argument	Required	Repeatable	Description
`<key>`	Yes	No	Redis key targeted by the command.
`NOMKSTREAM`	No	No	Do not create a missing stream.
`(KEEPREF \| DELREF \| ACKED)`	No	No	What happens to consumer-group references of the entries that trimming removes: `KEEPREF` (the default) leaves them in place, `DELREF` removes them from every group's pending list, and `ACKED` only removes entries that every group has read and acknowledged.
`(MAXLEN \| MINID) [= \| ~] <threshold> [LIMIT <count>]`	No	No	Trim the stream after the entry is added. `MAXLEN` caps the number of entries; `MINID` drops entries with a lower ID. `=` trims exactly and is the default; `~` trims approximately and is required before `LIMIT`, which caps how many entries a single call evicts.
`(* \| <id>)`	Yes	No	Entry ID: `*` lets the server generate one from the current time, or give an explicit `<milliseconds>-<sequence>` ID, which must be greater than the stream's last one.
`<field> <value>`	Yes	Yes	Field and the value to store in it. Repeat to set several fields in one call.

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	Bulk string or Null bulk string or null array
RESP3	Bulk string or Null

Note

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

Examples#

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

Redis CLI

XADD my-key * field value

@upstash/redis

import { Redis } from "@upstash/redis";const redis = Redis.fromEnv();const result = await redis.xadd("mystream", "*", { name: "John Doe", age: 30 });

upstash_redis

from upstash_redis import Redisredis = Redis.from_env()result = redis.xadd("my-key", "*", {"field": "value"})print(result)

ioredis

import Redis from "ioredis";const redis = new Redis(process.env.REDIS_URL!);const result = await redis.xadd("my-key", "*", "field", "value");console.log(result);

node-redis

import { createClient } from "redis";const client = await createClient({ url: process.env.REDIS_URL })  .on("error", console.error)  .connect();const result = await client.xAdd("my-key", "*", { field: "value" });console.log(result);

redis-py

import osimport redisclient = redis.from_url(os.environ["REDIS_URL"])result = client.xadd("my-key", {"field": "value"})print(result)

go-redis

package mainimport (    "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.XAdd(context.Background(), &redis.XAddArgs{Stream: "my-key", Values: map[string]interface{}{"field": "value"}}).Result()    if err != nil {        panic(err)    }    fmt.Println(result)}

jedis

import java.net.URI;import redis.clients.jedis.Jedis;try (Jedis jedis = new Jedis(new URI(System.getenv("REDIS_URL")))) {  Object result = jedis.xadd("my-key", redis.clients.jedis.StreamEntryID.NEW_ENTRY, java.util.Map.of("field", "value"));  System.out.println(result);}

redis-rs

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.xadd("my-key", "*", &[("field", "value")])?;    println!("{result:?}");    Ok(())}