---
title: "Set the multiview overlay alpha on a vision mixer block."
method: PUT
path: "/api/flows/{flow_id}/blocks/{block_id}/overlay-alpha"
tags: ["flows"]
---

# Set the multiview overlay alpha on a vision mixer block.

`PUT /api/flows/{flow_id}/blocks/{block_id}/overlay-alpha`

## Path parameters

- `flow_id` string, required
- `block_id` string, required

## Request body

- OverlayAlphaRequest — Request to set the multiview overlay alpha on a vision mixer block.
  - `alpha` number, double, required — Alpha value (0.0 = fully transparent, 1.0 = fully opaque)

## Response `200`

Overlay alpha set

- OverlayAlphaResponse — Response after setting the multiview overlay alpha.
  - `alpha` number, double, required
  - `message` string, required

## Other responses

- `400` — Invalid request

## Changes

- **2026-05-19** `b680d9fbbba8` — 1 info
  - endpoint added
- **2026-04-07** `1e67862a080e` — 1 breaking
  - api removed without deprecation

[Change history](https://skmtc.dev/eyevinn/apis/strom-api/changes/api/flows/:flow_id/blocks/:block_id/overlay-alpha/put.md)

---

[API](https://skmtc.dev/eyevinn/apis/strom-api.md) · [All operations](https://skmtc.dev/eyevinn/apis/strom-api/llms.txt) · [OpenAPI document](https://skmtc-service-production.skmtc.workers.dev/v1/apis/eyevinn/strom-api/revisions/0df7ca64263f/schema)