---
title: "Update a property on a running pipeline element."
method: PATCH
path: "/api/flows/{flow_id}/elements/{element_id}/properties"
tags: ["flows"]
---

# Update a property on a running pipeline element.

`PATCH /api/flows/{flow_id}/elements/{element_id}/properties`

Allows live modification of element properties while the pipeline is running.
Only properties marked as mutable in the current pipeline state can be updated.
The property mutability flags (mutable_in_playing, etc.) can be checked via
the element info endpoint.

## Path parameters

- `flow_id` string, required
- `element_id` string, required

## Request body

- UpdatePropertyRequest — Request to update a property on a running pipeline element.
  - `property_name` string, required — The name of the property to update
  - `ramp_ms` integer, nullable — Optional ramp duration in milliseconds. Currently honored for audio `volume`-element `volume` and `mute` updates — when set, `volume` is interpolated per-sample over the given duration (anti-zipper / fade) and `mute=true` is preceded by a fade-out of the same length while `mute=false` is followed by a 0→pre_mute fade-in. Useful for broadcast-style on-air / off-air route transitions (e.g. 500 ms). When omitted, a short default ramp is used for `volume`/`mute`; other properties are set immediately.
  - `value` union, required — Property value that can be various types. GStreamer properties can be strings, numbers, booleans, enums, etc.
    - string
    - integer
    - integer
    - number, double
    - boolean

## Response `200`

Property updated successfully

- ElementPropertiesResponse — Response containing current property values from a running element.
  - `element_id` string, required — The element ID
  - `properties` object, required — Current property values

## Other responses

- `400` — Property cannot be changed in current state or invalid value
- `404` — Flow not running or element not found
- `500` — Internal server error

## Changes

> 25 revisions in range; 17 could not be searched.

- **2026-04-07** `1e67862a080e` — 1 warning
  - removed the request property `ramp_ms`

[Change history](https://skmtc.dev/eyevinn/apis/strom-api/changes/api/flows/:flow_id/elements/:element_id/properties/patch.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)