---
title: "Create a session note"
method: POST
path: "/v1/session_notes"
tags: ["sessions"]
---

# Create a session note

`POST /v1/session_notes`

Add a note annotation to a session. By default each call appends a new note with an auto-generated UUIDv4 identifier, so multiple notes accumulate on the same session. Callers may supply a non-empty `identifier` to upsert on (session_id, name='note', identifier) — repeated calls with the same identifier overwrite the existing note, matching the semantics of structured annotations.

## Request body

- CreateSessionNoteRequestBody
  - `data` SessionNoteData, required
    - `session_id` string, required — Session ID
    - `note` string, required — The note text to add to the session
    - `identifier` string — Optional caller-supplied identifier. When non-empty, the note is upserted on (session_id, name='note', identifier) — repeated calls with the same identifier overwrite the existing note. When omitted or empty, the server stamps a unique 'px-session-note:<uuid>' identifier so each call appends a new note.

## Response `200`

Session note created successfully

- CreateSessionNoteResponseBody
  - `data` InsertedSessionAnnotation, required
    - `id` string, required — The ID of the inserted session annotation

## Other responses

- `403` — Forbidden
- `404` — Session not found
- `422` — Validation Error

---

[API](https://skmtc.net/arize-ai/apis/arize-phoenix-rest-api.md) · [All operations](https://skmtc.net/arize-ai/apis/arize-phoenix-rest-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/arize-ai/arize-phoenix-rest-api/versions/a14d8ad6f708/schema)