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curl --request POST \
  --url https://app.base44.com/api/apps/{app_id}/comments/threads/{thread_id}/replies \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "content": "Done, thanks!",
  "mentioned_emails": [
    "dana@acme.com"
  ]
}
'

import requests

url = "https://app.base44.com/api/apps/{app_id}/comments/threads/{thread_id}/replies"

payload = {
    "content": "Done, thanks!",
    "mentioned_emails": ["dana@acme.com"]
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({content: 'Done, thanks!', mentioned_emails: ['dana@acme.com']})
};

fetch('https://app.base44.com/api/apps/{app_id}/comments/threads/{thread_id}/replies', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://app.base44.com/api/apps/{app_id}/comments/threads/{thread_id}/replies",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'content' => 'Done, thanks!',
    'mentioned_emails' => [
        'dana@acme.com'
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

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

curl_close($curl);

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

package main

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

func main() {

	url := "https://app.base44.com/api/apps/{app_id}/comments/threads/{thread_id}/replies"

	payload := strings.NewReader("{\n  \"content\": \"Done, thanks!\",\n  \"mentioned_emails\": [\n    \"dana@acme.com\"\n  ]\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

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

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

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://app.base44.com/api/apps/{app_id}/comments/threads/{thread_id}/replies")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"content\": \"Done, thanks!\",\n  \"mentioned_emails\": [\n    \"dana@acme.com\"\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://app.base44.com/api/apps/{app_id}/comments/threads/{thread_id}/replies")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"content\": \"Done, thanks!\",\n  \"mentioned_emails\": [\n    \"dana@acme.com\"\n  ]\n}"

response = http.request(request)
puts response.read_body

{
  "id": "68e2b7c4d4f0a9001c3e5a1c",
  "content": "Make this button match the header color.",
  "sender_id": "6820f41be7b91d003c45a20a",
  "sender_name": "Dana Levi",
  "sender_avatar_url": "https://lh3.googleusercontent.com/a/ACg8ocJ2",
  "created_date": "2026-10-05T09:14:22.512000Z",
  "edited_at": "2026-10-05T09:14:22.512000Z",
  "reactions": {
    "👍": [
      "6820f41be7b91d003c45a20a"
    ]
  }
}

{
  "detail": [
    {
      "loc": [
        "<string>"
      ],
      "msg": "<string>",
      "type": "<string>"
    }
  ]
}

Comments

Reply to comment

This API is in beta. Endpoints, fields, and behavior may still change, so avoid depending on it in production.

Adds a reply to a comment thread. Replying to a resolved thread doesn’t reopen it.

mentioned_emails records who the comment mentions. Only emails that List mentionable users returns are kept, and the rest are dropped without an error. Mentioning someone sends them no email or notification, and responses never return the list.

Anyone with the app open in the builder sees the change right away.

This is limited to 120 requests per minute per app, shared by every other comments endpoint. A signed-in session has its own limit, and every personal access token for the workspace shares one. Some workspaces have a different limit. Every request that counts against the limit gets X-RateLimit-Limit, X-RateLimit-Remaining and X-RateLimit-Reset (Unix time in seconds) headers, and a 429 also gets Retry-After in seconds. If the limiter itself is unavailable, requests go through without these headers.

Call this as an editor of the app, with a personal access token sent as a Bearer token or from a signed-in session. Viewers in the app’s workspace, read-only tokens, and workspace API keys are refused.

POST

api

apps

{app_id}

comments

threads

{thread_id}

replies

Reply to comment

curl --request POST \
  --url https://app.base44.com/api/apps/{app_id}/comments/threads/{thread_id}/replies \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "content": "Done, thanks!",
  "mentioned_emails": [
    "dana@acme.com"
  ]
}
'

import requests

url = "https://app.base44.com/api/apps/{app_id}/comments/threads/{thread_id}/replies"

payload = {
    "content": "Done, thanks!",
    "mentioned_emails": ["dana@acme.com"]
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

response = requests.post(url, json=payload, headers=headers)

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({content: 'Done, thanks!', mentioned_emails: ['dana@acme.com']})
};

fetch('https://app.base44.com/api/apps/{app_id}/comments/threads/{thread_id}/replies', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://app.base44.com/api/apps/{app_id}/comments/threads/{thread_id}/replies",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'content' => 'Done, thanks!',
    'mentioned_emails' => [
        'dana@acme.com'
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "Content-Type: application/json"
  ],
]);

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

curl_close($curl);

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

package main

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

func main() {

	url := "https://app.base44.com/api/apps/{app_id}/comments/threads/{thread_id}/replies"

	payload := strings.NewReader("{\n  \"content\": \"Done, thanks!\",\n  \"mentioned_emails\": [\n    \"dana@acme.com\"\n  ]\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Authorization", "Bearer <token>")
	req.Header.Add("Content-Type", "application/json")

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

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

	fmt.Println(string(body))

}

HttpResponse<String> response = Unirest.post("https://app.base44.com/api/apps/{app_id}/comments/threads/{thread_id}/replies")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"content\": \"Done, thanks!\",\n  \"mentioned_emails\": [\n    \"dana@acme.com\"\n  ]\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://app.base44.com/api/apps/{app_id}/comments/threads/{thread_id}/replies")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"content\": \"Done, thanks!\",\n  \"mentioned_emails\": [\n    \"dana@acme.com\"\n  ]\n}"

response = http.request(request)
puts response.read_body

{
  "id": "68e2b7c4d4f0a9001c3e5a1c",
  "content": "Make this button match the header color.",
  "sender_id": "6820f41be7b91d003c45a20a",
  "sender_name": "Dana Levi",
  "sender_avatar_url": "https://lh3.googleusercontent.com/a/ACg8ocJ2",
  "created_date": "2026-10-05T09:14:22.512000Z",
  "edited_at": "2026-10-05T09:14:22.512000Z",
  "reactions": {
    "👍": [
      "6820f41be7b91d003c45a20a"
    ]
  }
}

{
  "detail": [
    {
      "loc": [
        "<string>"
      ],
      "msg": "<string>",
      "type": "<string>"
    }
  ]
}

Authorizations

Authorization

string

header

required

Personal access token, sent as Authorization: Bearer <token>.

Path Parameters

app_id

string

required

ID of the app.

thread_id

string

required

ID of the comment thread, from thread.id in List comments.

Body

application/json

A reply to a comment thread.

content

string

required

Text of the comment, 1 to 5000 characters.

Required string length: 1 - 5000

Example:

"Done, thanks!"

mentioned_emails

string[]

Emails of up to 50 people the comment mentions. Mentions send no notification.

Maximum array length: 50

Example:

["dana@acme.com"]

Response

The new reply.

One comment: the first comment of a thread or a reply.

string

required

ID of the comment.

Example:

"68e2b7c4d4f0a9001c3e5a1c"

content

string

required

Text of the comment.

Example:

"Make this button match the header color."

sender_id

string

required

ID of the Base44 user who wrote it, or base44 for a reply from the builder agent.

Example:

"6820f41be7b91d003c45a20a"

sender_name

string

required

Name of the author when they wrote it, or their email when they had no name. Base44 for the builder agent.

Example:

"Dana Levi"

sender_avatar_url

string | null

required

URL of the author's profile image, or null when they have none.

Example:

"https://lh3.googleusercontent.com/a/ACg8ocJ2"

created_date

string<date-time>

required

When the comment was posted, in UTC.

Example:

"2026-10-05T09:14:22.512000Z"

edited_at

string<date-time> | null

required

When the comment was last edited, in UTC, or null when it never was.

Example:

"2026-10-05T09:14:22.512000Z"

reactions

Reactions · object

required

Each emoji reacted with, mapped to the IDs of the users who reacted with it.

Show child attributes

Example:

{ "👍": ["6820f41be7b91d003c45a20a"] }

Base44 APIs

Apps API (Beta)

Workspace API (Beta)

Superagents API (Beta)

Monitoring API

Audit Logs API

Reply to comment

Authorizations

Path Parameters

Body

Response