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PopNx MCPMCP servers for people who use AI · explained in plain words

Quackr

by quackr-mcpversion 1.0.3i★ –iComputer or cloud
Registry nameio.quackr/quackr

Install

Overview

Description from the maker (original English)

Virtual phone numbers for SMS verification, OTP receipt, and number management.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

  • Connection: Computer or cloud
  • Transport: stdio, Streamable HTTP
  • Category: Chat & email
  • You need to fill in: QUACKR_API_KEY, Authorization

Install

Pick the AI app you use, then copy the settings.

Before you install

  • Basic checks: 1 of 1 passed
  • Runs on the maker’s server: what you ask it goes through their server.
  • You fill in yourself: QUACKR_API_KEY, Authorization

Values marked secret are keys to your account. Never share them or paste them into a chat.

You need

  • Runs in the cloudNothing to install; it connects over the internet
  • npmNode.js installed (for the npx command)

Which app do you use?

Pick your app above. We remember it, so next time the button says “Install in …”.

This address needs a key in a request header, which the add-connector menu cannot set. Use Claude Code, Cursor or VS Code instead.

Or run it on your computer

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "quackr": {
      "command": "npx",
      "args": [
        "-y",
        "quackr-mcp"
      ],
      "env": {
        "QUACKR_API_KEY": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add --transport http quackr https://mcp.quackr.io/ --header 'Authorization: your-value'

Or run it on your computer

claude mcp add quackr --env QUACKR_API_KEY=your-value -- npx -y quackr-mcp

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "quackr": {
      "url": "https://mcp.quackr.io/",
      "headers": {
        "Authorization": "your-value"
      }
    }
  }
}

Or run it on your computer

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "quackr": {
      "command": "npx",
      "args": [
        "-y",
        "quackr-mcp"
      ],
      "env": {
        "QUACKR_API_KEY": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "quackr": {
      "type": "http",
      "url": "https://mcp.quackr.io/",
      "headers": {
        "Authorization": "your-value"
      }
    }
  }
}

Or run it on your computer

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "quackr": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "quackr-mcp"
      ],
      "env": {
        "QUACKR_API_KEY": "your-value"
      }
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This address needs a key in a request header, which the add-connector menu cannot set. Use Claude Code, Cursor or VS Code instead.

Your choice stays on this device in a cookie; no account needed.

Values you fill in

  • QUACKR_API_KEY secret required env
    Your Quackr API key, from your profile page at quackr.io
  • Authorization secret required HTTP header
    Bearer token in the form 'Bearer ', from your profile page at quackr.io

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

We have not read this server’s tool list yet; we check endpoints in rotation.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 6, 2026

  • ✓ Pass

    Maker matches the repo

    The registry name was verified against the domain quackr.io (the registry checks domain ownership)

  • … Not checked yet

    Still maintained

    We have not read this repo from GitHub yet

  • … Not checked yet

    Has a licence

    We have not read this repo from GitHub yet

  • … Not checked yet

    Endpoint responds

    Not checked yet; we check endpoints in rotation

  • … Not checked yet

    Sign-in with OAuth

    Not checked yet; we check endpoints in rotation

  • … Not checked yet

    No hidden instructions in tool descriptions

    Not checked yet; we read the tool list when we check the endpoint

Compared with others in Chat & emaili

  • More stars than 0% of the other 1762 servers in this category
  • Published to the registry more recently than 13% of the other 1762 servers in this category
  • Basic checks equal to or better than 100% of the other 1762 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Quackr safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

You need to fill in: QUACKR_API_KEY, Authorization

Does it run on my computer or in the cloud?

Either way works: install it on your computer or connect to the cloud version.

Is it still maintained?

The GitHub repo last changed –, and the latest version (1.0.3) reached the registry 5 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. It connects by URL, so apps that accept remote MCP servers work too, such as ChatGPT in developer mode.

What can I use instead?

In the same category: Vexa, emailmd, MCP WhatsApp Cloud

Alternatives

Servers in the same category from other makers, sorted by stars.

Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

Vexa

by Vexa-ai

Meeting bot and transcripts for Google Meet, Teams and Zoom. Live or after, speakers labelled.

Runs in the cloud★ 2,949Apache-2.0Updated 2 months ago
Install

emailmd

by anypost

Render markdown into email-safe HTML, lint drafts for deliverability problems, and preview emails.

Computer or cloud★ 1,385MITUpdated 30 days ago
Install

MCP server for WhatsApp Cloud API (Meta) — messages, media, and templates via Graph API

Runs on your computer★ 277MITUpdated 5 months ago
Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

Quackr MCP Server

Official MCP server for Quackr — virtual phone numbers for SMS verification and OTP receipt. Use Claude (or any MCP-compatible client) to check pricing and inventory, purchase temporary numbers, and read incoming SMS programmatically.

  • npm: quackr-mcp — npx -y quackr-mcp
  • Hosted endpoint: https://mcp.quackr.io/
  • Transport: Streamable HTTP
  • Auth: Authorization: Bearer YOUR_API_KEY header

Tools

ToolDescription
get-balanceGet the current account balance in USD
get-pricingGet phone number rental pricing for a specific country
get-inventoryCheck available phone number inventory for a country
purchase-numberPurchase a temporary number for receiving SMS (deducts from balance)
check-smsCheck SMS messages received on a rented number
list-active-numbersList all currently active (rented) numbers on the account

Getting an API Key

  1. Sign in at quackr.io
  2. Open your profile page
  3. Copy the API key from the API section

Install via npm

The quackr-mcp package is a thin stdio launcher that bridges any stdio MCP client to the hosted Quackr endpoint. It needs Node.js 18+ — no separate install required, npx fetches it on first run.

{

"mcpServers": { "quackr": { "command": "npx", "args": ["-y", "quackr-mcp"], "env": { "QUACKR_API_KEY": "YOUR_API_KEY_HERE" } } } }

You can also pass the key as a flag instead of an env var: npx -y quackr-mcp --api-key YOUR_API_KEY_HERE.

Claude Code Setup

Remote (recommended) — connect directly to the hosted endpoint. Add to your ~/.claude.json (or a project .mcp.json):

{

"mcpServers": { "quackr": { "type": "http", "url": "https://mcp.quackr.io/", "headers": { "Authorization": "Bearer YOUR_API_KEY_HERE" } } } }

Or via the CLI:

claude mcp add --transport http quackr https://mcp.quackr.io/ --header "Authorization: Bearer YOUR_API_KEY_HERE"

Claude Desktop Setup

Claude Desktop's JSON config only supports local (stdio) servers. Use the npm launcher (see Install via npm) by adding the npx quackr-mcp config above to claude_desktop_config.json, then restart Claude Desktop.

Alternatively, add Quackr as a remote connector: Settings → Connectors → Add custom connector, enter https://mcp.quackr.io/, and add an Authorization header with the value Bearer YOUR_API_KEY.

Other MCP Clients

Any client supporting remote Streamable HTTP MCP servers with custom headers works. Point it at https://mcp.quackr.io/ and pass your key via the Authorization: Bearer YOUR_API_KEY header.

REST API

Quackr also exposes a full REST API at https://api.quackr.io/ — see api.quackr.io/swagger.json for the full spec. Same x-api-key auth.

Support

  • Website: quackr.io
  • Issues: file in this repo
  • Email: support@quackr.io

License

MIT — see LICENSE.

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