---
title: "Call Start Batch"
method: POST
path: "/call/upsert_batch"
tags: ["Calls"]
---

# Call Start Batch

`POST /call/upsert_batch`

## Request

- Base URL: `https://trace.wandb.ai` (the document declares no server; this is the origin it was published from)
- URL: `https://trace.wandb.ai/call/upsert_batch`
- Auth: none declared

## Request body

- CallCreateBatchReq
  - `batch` union[], required
    - union
      - CallBatchStartMode
        - `mode` string
        - `req` CallStartReq, required
          - `start` StartedCallSchemaForInsert, required
            - `project_id` string, required
            - `id` string, nullable
            - `op_name` string, required
            - `display_name` string, nullable
            - `trace_id` string, nullable
            - `parent_id` string, nullable
            - `thread_id` string, nullable
            - `turn_id` string, nullable
            - `started_at` string, date-time, required
            - `attributes` object, required
            - `inputs` object, required
            - `otel_dump` object, nullable
            - `wb_user_id` string, nullable: Do not set directly. Server will automatically populate this field.
            - `wb_run_id` string, nullable
            - `wb_run_step` integer, nullable
      - CallBatchEndMode
        - `mode` string
        - `req` CallEndReq, required
          - `end` EndedCallSchemaForInsert, required
            - `project_id` string, required
            - `id` string, required
            - `trace_id` string, nullable
            - `is_eval` boolean, nullable
            - `ended_at` string, date-time, required
            - `started_at` string, date-time, nullable
            - `exception` string, nullable
            - `output` unknown
            - `summary` SummaryInsertMap, required
              - …
            - `wb_run_step_end` integer, nullable

## Response `200`

Successful Response

- CallCreateBatchRes
  - `res` union[], required
    - union
      - CallStartRes
        - `id` string, required
        - `trace_id` string, required
      - CallEndRes

## Other responses

- `422`: Validation Error

## Changes

- **2026-10-16** `dd89fadfe4e4`: 8 info
  - the endpoint scheme security `HTTPBasic` was removed from the API
  - added the new optional request property `batch/items/anyOf[subschema #2: CallBatchEndMode]/req/end/is_eval`
  - added the new optional request property `batch/items/anyOf[subschema #2: CallBatchEndMode]/req/end/started_at`
  - added the new optional request property `batch/items/anyOf[subschema #2: CallBatchEndMode]/req/end/summary/usage/additionalProperties/cache_creation_input_tokens`
  - …4 more
- **2025-11-05** `f4a10b6a2e6d`: 2 info
  - added the new optional request property `batch/items/anyOf[subschema #1: CallBatchStartMode]/req/start/otel_dump`
  - added the new optional request property `batch/items/anyOf[subschema #2: CallBatchEndMode]/req/end/wb_run_step_end`

[Operation history](https://skmtc.dev/wandb/apis/weights-biases-weave-stainless-api/changes/call/upsert_batch/post.md)

---

[API](https://skmtc.dev/wandb/apis/weights-biases-weave-stainless-api.md) - [All operations](https://skmtc.dev/wandb/apis/weights-biases-weave-stainless-api/llms.txt) - [OpenAPI document](https://skmtc.dev/wandb/apis/weights-biases-weave-stainless-api/revisions/f7643c49bf2e?raw)