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POST
/
streams
/
{stream}
/
records
Append records.
curl --request POST \
  --url https://{basin}.b.s2.dev/v1/streams/{stream}/records \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "records": [
    {
      "body": "<string>",
      "headers": [
        [
          "<string>"
        ]
      ],
      "timestamp": 1
    }
  ]
}
'
{
  "end": {
    "seq_num": 1,
    "timestamp": 1
  },
  "start": {
    "seq_num": 1,
    "timestamp": 1
  },
  "tail": {
    "seq_num": 1,
    "timestamp": 1
  }
}

Documentation Index

Fetch the complete documentation index at: https://s2.dev/docs/llms.txt

Use this file to discover all available pages before exploring further.

Append concepts

Understand append acknowledgements, batching, and durability.

Concurrency control

Coordinate writers with match sequence numbers and fencing tokens.

Appending SDK

Use append sessions, the Producer API, batching, and backpressure.

Authorizations

​
Authorization
string
header
required

Bearer authentication header of the form Bearer <token>, where <token> is your access token.

Headers

​
s2-format
enum<string>

Defines the interpretation of record data (header name, header value, and body) with the JSON content type. Use raw (default) for efficient transmission and storage of Unicode data — storage will be in UTF-8. Use base64 for safe transmission with efficient storage of binary data.

Available options:
raw,
base64
​
s2-encryption-key
string

Encryption key material for append and read operations. Provide base64-encoded key when stream encryption is enabled.

Path Parameters

​
stream
string
required

Stream name.

Required string length: 1 - 512

Body

application/json

Payload of an append request.

​
records
object[]
required

Batch of records to append atomically, which must contain at least one record, and no more than 1000. The total size of a batch of records may not exceed 1 MiB of metered bytes.

​
fencing_token
null | string

Enforce a fencing token, which starts out as an empty string that can be overridden by a fence command record.

Maximum string length: 36
​
match_seq_num
null | integer<int64>

Enforce that the sequence number assigned to the first record matches.

Required range: x >= 0

Response

Success response to an append request.

​
end
object
required

Sequence number of the last record that was appended + 1, and timestamp of the last record that was appended. The difference between end.seq_num and start.seq_num will be the number of records appended.

​
start
object
required

Sequence number and timestamp of the first record that was appended.

​
tail
object
required

Sequence number that will be assigned to the next record on the stream, and timestamp of the last record on the stream. This can be greater than the end position in case of concurrent appends.