---
title: "Diff a candidate version against a baseline over the last N sealed runs (zero side effects)"
method: POST
path: "/v1/apps/{id}/replay/verdict-diff"
tags: ["Apps"]
---

# Diff a candidate version against a baseline over the last N sealed runs (zero side effects)

`POST /v1/apps/{id}/replay/verdict-diff`

## Request

- Base URL: `https://api.talonic.com`
- URL: `https://api.talonic.com/v1/apps/{id}/replay/verdict-diff`
- Auth: HTTP bearer

Pre-publish confidence. Replays both versions over the SAME frozen input packages of the app's most recent sealed runs and reports which subjects change verdict and how each rule's pass/fail footprint moves. Reads only: nothing is persisted, no actions fire, and the candidate is never activated. The LLM adjudicator is withheld so the diff is free and repeatable. Supply the candidate as inline `content` or `candidateVersionId`; with neither, the app's current draft is used.

## Path parameters

- `id` string, uuid, required

## Request body

- object
  - `candidateVersionId` string, uuid
  - `content` object: Unsaved manifest content to evaluate as the candidate.
  - `againstVersionId` string, uuid: Baseline version; defaults to the active version.
  - `lastNRuns` integer

## Response `200`

The verdict diff.

- object
  - `runsCompared` integer
  - `flips` object[]
    - `runId` string, uuid
    - `subjectKey` string, nullable: null for single-decision apps.
    - `from` string
    - `to` string
  - `ruleDeltas` object[]
    - `ruleId` string
    - `name` string
    - `passesBefore` integer
    - `passesAfter` integer
    - `failsBefore` integer
    - `failsAfter` integer
  - `summary` object
    - `totalSubjects` integer
    - `flippedSubjects` integer

## Other responses

- `404`: The requested resource was not found.
- `422`: No candidate to compare
- `501`: Verdict diff is not available in this deployment.

---

[API](https://skmtc.dev/talonic/apis/talonic-api.md) · [All operations](https://skmtc.dev/talonic/apis/talonic-api/llms.txt) · [OpenAPI document](https://skmtc.dev/talonic/apis/talonic-api/revisions/678fe5f8c9c3?raw)