Skip to content
POST/api/v1/evals/pairwise

Create a pairwise comparison or submit a vote

Action-discriminated. action='create' inserts a head-to-head A-vs-B comparison; action='vote' records a winner (a|b|tie), updates ELO ratings, and completes the comparison. projectId is required for both.

Authentication

Send Authorization: Bearer YOUR_API_KEY on every request. Generate API keys at /dashboard/settings/api-keys.

Request body required

Schema
{
  "application/json": {
    "schema": {
      "oneOf": [
        {
          "type": "object",
          "properties": {
            "action": {
              "type": "string",
              "enum": [
                "create"
              ]
            },
            "projectId": {
              "type": "string",
              "format": "uuid",
              "pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$"
            },
            "inputText": {
              "type": "string",
              "minLength": 1,
              "maxLength": 100000
            },
            "responseA": {
              "type": "string",
              "minLength": 1,
              "maxLength": 100000
            },
            "responseB": {
              "type": "string",
              "minLength": 1,
              "maxLength": 100000
            },
            "modelA": {
              "type": "string",
              "maxLength": 120
            },
            "modelB": {
              "type": "string",
              "maxLength": 120
            },
            "metadata": {
              "type": "object",
              "additionalProperties": {}
            }
          },
          "required": [
            "action",
            "projectId",
            "inputText",
            "responseA",
            "responseB"
          ],
          "additionalProperties": false
        },
        {
          "type": "object",
          "properties": {
            "action": {
              "type": "string",
              "enum": [
                "vote"
              ]
            },
            "projectId": {
              "type": "string",
              "format": "uuid",
              "pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$"
            },
            "comparisonId": {
              "type": "string",
              "format": "uuid",
              "pattern": "^([0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[1-8][0-9a-fA-F]{3}-[89abAB][0-9a-fA-F]{3}-[0-9a-fA-F]{12}|00000000-0000-0000-0000-000000000000|ffffffff-ffff-ffff-ffff-ffffffffffff)$"
            },
            "winner": {
              "type": "string",
              "enum": [
                "a",
                "b",
                "tie"
              ]
            },
            "feedback": {
              "type": "string",
              "maxLength": 20000
            }
          },
          "required": [
            "action",
            "projectId",
            "comparisonId",
            "winner"
          ],
          "additionalProperties": false
        }
      ]
    }
  }
}

Response

200 example

{
  "success": true
}

All status codes

200Vote recorded; ELO updated.
201Comparison created.
400(no description)
401(no description)
403Forbidden — the credential is valid but lacks the API-key scope, member role, or plan entitlement this operation requires.
404(no description)
409Conflict — CONFLICT.
429(no description)
500Internal Server Error — DB_ERROR.
501Not Implemented — TABLE_MISSING.

Code samples

cURL

curl -X POST \
  https://evalguard.ai/api/v1/evals/pairwise \
  -H "Authorization: Bearer $EVALGUARD_API_KEY"

TypeScript

// The TypeScript SDK (@evalguard/sdk) exposes TYPED methods — runEval,
// getEval, runSecurityScan, checkFirewall, … — not a generic request().
// For an arbitrary endpoint, call it directly:

const res = await fetch("https://evalguard.ai/api/v1/evals/pairwise", {
  method: "POST",
  headers: { Authorization: `Bearer ${process.env.EVALGUARD_API_KEY}` },
});
console.log(res.status, await res.json());

Python

# The Python SDK (pip install evalguardai) exposes TYPED methods on
# EvalGuardClient — run_eval, get_eval, … — not a generic request().
# For an arbitrary endpoint, call it directly:

import os
import requests

headers = {"Authorization": f"Bearer {os.environ['EVALGUARD_API_KEY']}"}

response = requests.request("POST", "https://evalguard.ai/api/v1/evals/pairwise", headers=headers)
print(response.status_code, response.json())

Go

package main

import (
	"context"
	"fmt"
	"net/http"
	"os"
)

func main() {
	req, _ := http.NewRequestWithContext(context.Background(), "POST", "https://evalguard.ai/api/v1/evals/pairwise", nil)
	req.Header.Set("Authorization", "Bearer "+os.Getenv("EVALGUARD_API_KEY"))
	resp, err := http.DefaultClient.Do(req)
	if err != nil { panic(err) }
	defer resp.Body.Close()
	fmt.Println(resp.Status)
}

Errors

400401403404409429500501

Other Evals endpoints