curl --request GET \
  --url https://commet.co/api/v1/plans/{id}/versions/{versionId}/changes \
  --header 'x-api-key: <api-key>'

const options = {method: 'GET', headers: {'x-api-key': '<api-key>'}};

fetch('https://commet.co/api/v1/plans/{id}/versions/{versionId}/changes', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

import requests

url = "https://commet.co/api/v1/plans/{id}/versions/{versionId}/changes"

headers = {"x-api-key": "<api-key>"}

response = requests.get(url, headers=headers)

print(response.text)

package main

import (
	"fmt"
	"net/http"
	"io"
)

func main() {

	url := "https://commet.co/api/v1/plans/{id}/versions/{versionId}/changes"

	req, _ := http.NewRequest("GET", url, nil)

	req.Header.Add("x-api-key", "<api-key>")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.get("https://commet.co/api/v1/plans/{id}/versions/{versionId}/changes")
  .header("x-api-key", "<api-key>")
  .asString();

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://commet.co/api/v1/plans/{id}/versions/{versionId}/changes",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "GET",
  CURLOPT_HTTPHEADER => [
    "x-api-key: <api-key>"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}

{
  "versionId": "plr_9i0j1k2l",
  "againstVersionId": "plr_5m6n7o8p",
  "changes": [
    {
      "key": "price:pp_1a2b3c4d",
      "section": "Price",
      "country": null,
      "label": "Monthly price",
      "before": "$49.00",
      "after": "$59.00"
    },
    {
      "key": "feature:pf_9z8y7x6w",
      "section": "What's included",
      "country": null,
      "label": "Agent runs",
      "before": "1,000 included",
      "after": "2,000 included"
    }
  ]
}

{
  "error": {
    "type": "validation_error",
    "code": "validation_error",
    "message": "The request contains an invalid parameter.",
    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/validation_error.md"
  }
}

{
  "error": {
    "type": "authentication_error",
    "code": "unauthorized",
    "message": "A valid API key is required.",
    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/unauthorized.md"
  }
}

{
  "error": {
    "type": "authentication_error",
    "code": "forbidden",
    "message": "You do not have permission to perform this operation.",
    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/forbidden.md"
  }
}

{
  "error": {
    "type": "not_found_error",
    "code": "not_found",
    "message": "The requested resource was not found.",
    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/not_found.md"
  }
}

{
  "error": {
    "type": "rate_limit_error",
    "code": "rate_limited",
    "message": "Too many requests. Retry after the interval specified in the Retry-After header.",
    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/rate_limited.md"
  }
}

{
  "error": {
    "type": "internal_error",
    "code": "internal_error",
    "message": "An unexpected error occurred while processing the request.",
    "doc_url": "https://commet.co/docs/api-reference/2026-08-27/errors/internal_error.md"
  }
}