Social media character counter API

Paste a post and see at once how it fits on X, Threads, Bluesky, Mastodon, LinkedIn, Instagram, Facebook, TikTok, Pinterest, YouTube and Google Business Profile.

• Endpoint: POST https://postboost.co/app/api/tools/social-media-character-counter (operationId countCharacters)
• Web tool: postboost.co/tools/social-media-character-counter
• Also on the web: X character counter (network: "x"), Threads character counter (network: "threads"), Bluesky character counter (network: "bluesky")
• Token: optional (limits)
• MCP: tool count-characters on https://postboost.co/mcp/tools

Request

Field	Type	Default	Description
text	string	""	The post text, up to 10,000 characters (twice the longest network limit); 5,000 without an API token.
network	string: x, threads, bluesky, mastodon, linkedin, instagram, facebook, tiktok, pinterest, youtube_title, youtube, gbp		Count for one network only; all networks when omitted.

Call it

curl

curl -X POST https://postboost.co/app/api/tools/social-media-character-counter \
  -H 'Content-Type: application/json' \
  -d '{"text":"New post: https://postboost.co/tools","network":"x"}'

Python

from postboost import ApiClient, Configuration
from postboost.api.free_tools_api import FreeToolsApi
from postboost.models import FreeToolCountCharactersRequest

with ApiClient(Configuration()) as client:
    api = FreeToolsApi(client)
    result = api.count_characters(FreeToolCountCharactersRequest.from_dict({"text": "New post: https://postboost.co/tools", "network": "x"}))
    print(result.to_dict())

Node.js

import { FreeToolsApi } from 'postboost';

const api = new FreeToolsApi();
const { body } = await api.countCharacters({ text: "New post: https://postboost.co/tools", network: "x" });
console.log(body);

PHP

use PostBoostClient\Api\FreeToolsApi;
use PostBoostClient\Model\FreeToolCountCharactersRequest;

$api = new FreeToolsApi(new GuzzleHttp\Client());
$result = $api->countCharacters(new FreeToolCountCharactersRequest(['text' => "New post: https://postboost.co/tools", 'network' => "x"]));
echo $result;

Go

import (
    "context"
    "encoding/json"
    "fmt"

    postboost "github.com/postboost-co/postboost-go"
)

var request postboost.FreeToolCountCharactersRequest
if err := json.Unmarshal([]byte(`{"text":"New post: https://postboost.co/tools","network":"x"}`), &request); err != nil {
    panic(err)
}

client := postboost.NewAPIClient(postboost.NewConfiguration())
result, _, err := client.FreeToolsAPI.CountCharacters(context.Background()).FreeToolCountCharactersRequest(request).Execute()
fmt.Println(result, err)

Ruby

require 'postboost'

api = PostBoost::FreeToolsApi.new
result = api.count_characters(PostBoost::FreeToolCountCharactersRequest.new({ text: "New post: https://postboost.co/tools", network: "x" }))
puts result.to_hash

Java

import com.postboost.ApiClient;
import com.postboost.api.FreeToolsApi;
import com.postboost.model.FreeToolCountCharactersRequest;
import com.postboost.model.FreeToolCountCharactersResponse;

FreeToolsApi api = new FreeToolsApi(new ApiClient());
FreeToolCountCharactersRequest request = FreeToolCountCharactersRequest.fromJson("{\"text\":\"New post: https://postboost.co/tools\",\"network\":\"x\"}");
FreeToolCountCharactersResponse result = api.countCharacters(request);
System.out.println(result.toJson());

C#

using Newtonsoft.Json;
using PostBoost.Client.Api;
using PostBoost.Client.Client;
using PostBoost.Client.Model;

var api = new FreeToolsApi(new Configuration());
var request = JsonConvert.DeserializeObject<FreeToolCountCharactersRequest>(@"{""text"":""New post: https://postboost.co/tools"",""network"":""x""}");
var result = await api.CountCharactersAsync(request);
Console.WriteLine(result.ToJson());

Rust

use postboost::apis::configuration::Configuration;
use postboost::apis::free_tools_api;
use postboost::models::FreeToolCountCharactersRequest;

let config = Configuration::new();
let request: FreeToolCountCharactersRequest = serde_json::from_str(r##"{"text":"New post: https://postboost.co/tools","network":"x"}"##)?;
let result = free_tools_api::count_characters(&config, request).await?;
println!("{:?}", result);

CLI

echo '{"text":"New post: https://postboost.co/tools","network":"x"}' | ./postboost-cli --content-type application/json countCharacters -

With a token, send Authorization: Bearer YOUR_API_TOKEN as a default header (how, per SDK).

Response

{
    "hashtags": 0,
    "networks": [
        {
            "key": "x",
            "label": "X (Twitter) post",
            "limit": 280,
            "count": 33,
            "remaining": 247,
            "over": false
        }
    ]
}

With MCP

Connect https://postboost.co/mcp/tools (setup) and ask, for example: Count characters as each network counts them with the PostBoost count-characters tool.

Errors

Status	When
401	The Authorization header holds an invalid token. Leave it out to call as a guest.
413	The JSON body is larger than 128 KB.
422	A field is invalid; the body lists the errors per field.
429	A limit is reached; see limits.