---
title: "Save a successor model replacement"
method: PUT
path: "/routing/successor/replacements"
tags: ["Gateway"]
---

# Save a successor model replacement

`PUT /routing/successor/replacements`

## Request

- Base URL: `https://api.phaseo.app/v1`
- URL: `https://api.phaseo.app/v1/routing/successor/replacements`
- Auth: HTTP bearer

Sets the model that requests for model are sent to, replacing any earlier choice. A null successor means requests for model are never redirected. Both models must be in the catalogue and the successor must be served. At most 500 per workspace. Owners and admins; settings:write required.

## Request body

- SuccessorReplacement
  - `model` string, required: The model whose requests are redirected.
  - `successor` string, nullable, required: The model to send them to, or null to never redirect them.

## Response `200`

Saved replacement

- SuccessorReplacementResponse
  - `data` SuccessorReplacementRow, required
    - `model` string
    - `successor` string, nullable
    - `updated_at` string, date-time, nullable

## Other responses

- `400`: Invalid or unknown model
- `401`: Unauthorized

## Changes

- **2026-10-28** `72ba9c856a2c`: 1 info
  - endpoint added

[Operation history](https://skmtc.dev/phaseo/apis/phaseo-gateway-api/changes/routing/successor/replacements/put.md)

---

[API](https://skmtc.dev/phaseo/apis/phaseo-gateway-api.md) - [All operations](https://skmtc.dev/phaseo/apis/phaseo-gateway-api/llms.txt) - [OpenAPI document](https://skmtc.dev/phaseo/apis/phaseo-gateway-api/revisions/5ca9bb220d25?raw)