SOCIAL MEDIA
Reddit - post a comment as a registered app API
Posts a comment through Reddit's documented OAuth2 API using a refresh token, with the caller's own User-Agent. Verifies the token's account against expectedUsername before creating anything, and turns Reddit's HTTP-200 `json.errors` refusals (locked thread, subreddit ban, rate limit) into classified failures. No browser, no captcha, no cookies.
How to call it
Send one POST to api.upapi.io/reddit-oauth-post-comment.post with your key in the X-Api-Key header and the parameters below as a JSON body. Each call spends 4 weighted units of your monthly quota. The operation times out after 60 seconds. Responses are not cached; every call runs the operation.
POST https://api.upapi.io/reddit-oauth-post-comment.post
Reddit - post a comment as a registered app API reference
Request parameters
- text
- stringrequired — The comment body, markdown, exactly as it will appear.
- thingId
- stringrequired — Fullname of what is being replied to:
t3_<id>for a post,t1_<id>for another comment. This is the complete address of the parent -- unlike the cookie path, no page URL is needed or accepted. - clientId
- stringrequired — Reddit app client id
- proxyUrl
- string — Optional exit IP. Omit for the worker's default egress -- the OAuth lane has no per-account IP requirement of its own.
- userAgent
- stringrequired — The User-Agent this request is made with, sent verbatim. REQUIRED and never defaulted -- Reddit's API rules ask for a descriptive UA naming the app.
- clientSecret
- stringrequired — Reddit app client secret. Never logged.
- refreshToken
- stringrequired — OAuth2 refresh token for the posting account. Never logged, never returned.
- expectedUsername
- stringrequired — The account this comment must be attributed to. REQUIRED, unlike on the read operation: a refresh token is opaque, so without this a mis-filed credential posts under an identity nobody chose -- and every gate upstream reasoned about a different account. Compared against the name Reddit itself reports, before anything is created.
Response fields
- postedAs
- stringrequired — The username Reddit reported for the token, echoed so a caller records who actually spoke rather than who it believed it had asked for.
- commentId
- stringrequired — The new comment's id, without the
t1_prefix - elapsedMs
- integerrequired
- permalink
- stringrequired — Absolute permalink to the comment. Reddit returns a site-relative path; it is made absolute here so no caller has to know which host to prepend.
- createdUtc
- numberrequired — Creation time Reddit recorded, epoch seconds UTC
- parentThingId
- stringrequired — The fullname this comment replies to
- commentFullname
- stringrequired — The new comment's fullname, e.g.
t1_abc123
Example request and response
The example response is generated from this operation’s published output schema — it shows the shape and field names, not values from a recorded call.
{
"text": "Hello, world",
"thingId": "example",
"clientId": "example",
"userAgent": "example",
"clientSecret": "example",
"refreshToken": "example",
"expectedUsername": "example"
}{
"postedAs": "example",
"commentId": "example",
"elapsedMs": 1,
"permalink": "example",
"createdUtc": 1,
"parentThingId": "example",
"commentFullname": "`t1_abc123`"
}Code snippets
cURL
curl -X POST https://api.upapi.io/reddit-oauth-post-comment.post \
-H 'Content-Type: application/json' \
-H 'x-api-key: YOUR_API_KEY' \
-d '{ "text": "Hello, world", "thingId": "example", "clientId": "example", "userAgent": "example", "clientSecret": "example", "refreshToken": "example", "expectedUsername": "example" }'JavaScript
const response = await fetch('https://api.upapi.io/reddit-oauth-post-comment.post', {
method: 'POST',
headers: {
'Content-Type': 'application/json',
'x-api-key': 'YOUR_API_KEY',
},
body: JSON.stringify({
"text": "Hello, world",
"thingId": "example",
"clientId": "example",
"userAgent": "example",
"clientSecret": "example",
"refreshToken": "example",
"expectedUsername": "example"
}),
});
const data = await response.json();
console.log(data);Python
import requests
response = requests.post(
'https://api.upapi.io/reddit-oauth-post-comment.post',
headers={
'Content-Type': 'application/json',
'x-api-key': 'YOUR_API_KEY',
},
json={
"text": "Hello, world",
"thingId": "example",
"clientId": "example",
"userAgent": "example",
"clientSecret": "example",
"refreshToken": "example",
"expectedUsername": "example"
},
)
print(response.json())Go
package main
import (
"bytes"
"encoding/json"
"fmt"
"io"
"net/http"
)
func main() {
payload := []byte(`{ "text": "Hello, world", "thingId": "example", "clientId": "example", "userAgent": "example", "clientSecret": "example", "refreshToken": "example", "expectedUsername": "example" }`)
req, _ := http.NewRequest("POST", "https://api.upapi.io/reddit-oauth-post-comment.post", bytes.NewBuffer(payload))
req.Header.Set("Content-Type", "application/json")
req.Header.Set("x-api-key", "YOUR_API_KEY")
client := &http.Client{}
resp, err := client.Do(req)
if err != nil {
panic(err)
}
defer resp.Body.Close()
body, _ := io.ReadAll(resp.Body)
var result map[string]any
json.Unmarshal(body, &result)
fmt.Println(result)
}PHP
<?php
$payload = json_encode([
'text' => 'Hello, world',
'thingId' => 'example',
'clientId' => 'example',
'userAgent' => 'example',
'clientSecret' => 'example',
'refreshToken' => 'example',
'expectedUsername' => 'example',
]);
$ch = curl_init('https://api.upapi.io/reddit-oauth-post-comment.post');
curl_setopt_array($ch, [
CURLOPT_POST => true,
CURLOPT_POSTFIELDS => $payload,
CURLOPT_RETURNTRANSFER => true,
CURLOPT_HTTPHEADER => [
'Content-Type: application/json',
'x-api-key: YOUR_API_KEY',
],
]);
$response = curl_exec($ch);
curl_close($ch);
$data = json_decode($response, true);
var_dump($data);Ruby
require 'net/http'
require 'uri'
require 'json'
uri = URI('https://api.upapi.io/reddit-oauth-post-comment.post')
http = Net::HTTP.new(uri.host, uri.port)
http.use_ssl = uri.scheme == 'https'
request = Net::HTTP::Post.new(uri.path)
request['Content-Type'] = 'application/json'
request['x-api-key'] = 'YOUR_API_KEY'
request.body = { "text": "Hello, world", "thingId": "example", "clientId": "example", "userAgent": "example", "clientSecret": "example", "refreshToken": "example", "expectedUsername": "example" }.to_json
response = http.request(request)
puts JSON.parse(response.body)Java
import okhttp3.*;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.Map;
OkHttpClient client = new OkHttpClient();
ObjectMapper mapper = new ObjectMapper();
String json = "{ \"text\": \"Hello, world\", \"thingId\": \"example\", \"clientId\": \"example\", \"userAgent\": \"example\", \"clientSecret\": \"example\", \"refreshToken\": \"example\", \"expectedUsername\": \"example\" }";
RequestBody body = RequestBody.create(json, MediaType.get("application/json"));
Request request = new Request.Builder()
.url("https://api.upapi.io/reddit-oauth-post-comment.post")
.post(body)
.addHeader("Content-Type", "application/json")
.addHeader("x-api-key", "YOUR_API_KEY")
.build();
try (Response response = client.newCall(request).execute()) {
Map<?, ?> result = mapper.readValue(response.body().string(), Map.class);
System.out.println(result);
}C#
using System.Net.Http;
using System.Net.Http.Json;
using System.Text.Json;
using var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", "YOUR_API_KEY");
var payload = JsonSerializer.Deserialize<object>("{ \"text\": \"Hello, world\", \"thingId\": \"example\", \"clientId\": \"example\", \"userAgent\": \"example\", \"clientSecret\": \"example\", \"refreshToken\": \"example\", \"expectedUsername\": \"example\" }");
var response = await client.PostAsJsonAsync("https://api.upapi.io/reddit-oauth-post-comment.post", payload);
var result = await response.Content.ReadFromJsonAsync<JsonElement>();
Console.WriteLine(result);Frequently asked questions
How much does the Reddit - post a comment as a registered app API cost per call?
Each call spends 4 weighted units of your plan's monthly quota. Full pricing is at https://upapi.io/pricing.
How do I authenticate to the Reddit - post a comment as a registered app API?
Send your key in the X-Api-Key header. A free guest key is available without creating an account.
Are Reddit - post a comment as a registered app API responses cached?
No — every call runs the operation live; responses are not cached.