Intermediate SMS Gateway Free & Open Source Trending on GitHub
What is httpSMS?
Developed by NdoleStudio, httpSMS is an open-source service that transforms your everyday Android smartphone into a powerful, programmable SMS gateway. Instead of paying commercial providers like Twilio or MessageBird for virtual numbers and per-message API fees, httpSMS routes HTTP API requests directly through your phone’s existing cellular plan.
The system consists of a backend routing server (written in Go) and a lightweight Android application. When you trigger an API request from your website, server, or smart home hub, the backend instantly pushes the command to your phone, which sends the text message using your carrier. It can also receive replies and forward them to your webhooks, making it an incredibly cost-effective tool for two-way communication.
Who is it for?
- Indie Developers & Makers: Builders who want to add SMS notifications, 2FA, or alerts to their hobby projects without signing up for expensive, recurring commercial SMS plans.
- Small Businesses: Shops wanting to send appointment reminders or local marketing blasts using an unlimited texting plan they already pay for.
- IT Administrators: Systems engineers needing an out-of-band alert system (like server downtime notifications) routed through a physical SIM card.
- Privacy Advocates: Users who require End-to-End Encrypted (E2EE) text messaging that bypasses carrier snooping by encrypting the payload before it leaves the device.
What makes it special?
- Zero Per-Message Cost: Leverages your mobile carrier plan. If you have unlimited texting, your API messaging is essentially free.
- Smart Rate Limiting: Sending hundreds of automated texts at once will trigger carrier spam filters. httpSMS features a built-in queue system that paces messages (e.g., 1 message every 20 seconds) to keep your SIM safe.
- Real-Time Webhooks: Automatically forwards any incoming SMS messages to your server, Slack, Discord, or Zapier via callback URLs.
- Military-Grade Privacy: Built-in AES-256 encryption ensures that even the server routing the messages cannot read their contents—only the designated devices hold the decryption keys.
Requirements before you start
- Hardware: An Android smartphone (Android 8.0 or higher) with an active SIM card.
- Carrier Plan: A mobile plan with a generous or unlimited SMS allowance.
- Network: The Android phone must maintain a steady Wi-Fi or cellular data connection to receive API commands from the server.
- Account: A free account on the hosted httpsms.com platform, or a Linux server with Docker if you prefer to self-host the Go backend entirely.
Step-by-step installation
Step 1 — Generate Your API Key
For the easiest setup, we will use the hosted community version. If you are deploying the backend on your own server, complete your Docker setup first.
- Navigate to httpsms.com and create a free account.
- Go to your Settings dashboard.
- Generate a new API Key. Save this somewhere safe; you will need it for both the Android app and your code.
Step 2 — Install the Android Companion App
The Android app acts as the bridge between the API and your phone’s SMS hardware.
- On your Android phone, download the latest APK directly from the GitHub releases page:
https://github.com/NdoleStudio/httpsms/releases - Install the app (you may need to allow installation from unknown sources).
- Open the app and grant it the required permissions (SMS read/write and Contacts).
- Log in by pasting the API Key you generated in Step 1.
Step 3 — Prevent Android Battery Optimization
To ensure your phone doesn’t fall asleep and miss API requests, you must disable battery optimization for the httpSMS app.
- Go to your phone’s Settings > Apps > httpSMS > Battery.
- Set the usage to Unrestricted.
Step 4 — Send Your First SMS via API
With the phone connected and listening, you can now trigger a text message from any terminal or application using a simple HTTP POST request.
curl --location --request POST 'https://api.httpsms.com/v1/messages/send' \
--header 'x-api-key: YOUR_API_KEY_HERE' \
--header 'Content-Type: application/json' \
--data-raw '{
"from": "+15551234567",
"to": "+15559876543",
"content": "Hello from the httpSMS API!"
}'Note: Replace the “from” number with your actual Android phone number, and the “to” number with the destination.
Common errors and fixes
| Error | Meaning | Fix |
|---|---|---|
| 401 Unauthorized | The server rejected your API request. | Verify that your x-api-key header is correctly formatted and that you haven’t accidentally included trailing spaces. |
| Messages stuck in “Queued” | The API received the request, but the Android phone is not retrieving it to send via the cellular network. | Your phone is either disconnected from Wi-Fi/Data, or Android OS killed the background app. Disable battery optimization for httpSMS and open the app to force a sync. |
| Carrier Spam Block | Your messages fail to deliver, or your carrier temporarily suspends your texting capability. | You are sending automated messages too quickly. Utilize the built-in rate-limiting feature in the dashboard to pace your outbound texts. |
Free vs Paid comparison
| Feature | httpSMS (Open Source) | Commercial APIs (Twilio, MessageBird) |
|---|---|---|
| Pricing Model | Free API, utilizes your phone’s SMS plan | Pay per message + monthly number rental |
| Phone Number | Your real, physical SIM number | A leased virtual VoIP number |
| End-to-End Encryption | Supported natively | Not available; provider can read logs |
| Hardware Requirement | Requires a dedicated Android phone | None, 100% cloud-based |
Bottom line: httpSMS is a brilliant, budget-friendly workaround for developers who need robust SMS automation without the recurring costs of enterprise gateways. By turning an old Android device into a dedicated SMS server, you reclaim ownership over your communication stack.
Alternatives — 3 similar tools
- TextBee A very similar open-source SMS gateway for Android. TextBee offers a slightly simpler setup process and a clean dashboard for managing multiple devices, making it a strong direct competitor if you are building an offline messaging hub.
🔗 textbee.dev - Gotify If you don’t actually need to send SMS messages, but simply want to push notifications from your server to your Android phone, Gotify is an incredible self-hosted push notification server that doesn’t rely on cellular text plans.
🔗 gotify.net - Twilio The enterprise standard. If your application needs to send tens of thousands of messages an hour, a physical Android phone will not suffice. Twilio offers massive scale, reliability, and international compliance, though it comes at a premium cost.
🔗 twilio.com
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