How to Send SMS with Bitcoin Lightning

The Problem with Sending SMS Today

International SMS on most carrier plans costs $0.25-0.50 per message — if your plan supports it at all. Many carriers block international texting entirely or require an add-on package. Prepaid SIMs charge even more. And every message you send is tied to your phone number, your name, and your carrier account.

Online SMS services solve some of these problems but introduce new ones: account creation, email verification, credit card on file, credits that expire, and rate limits. Most are US/EU-focused and charge extra for other regions.

For developers and businesses, sending SMS programmatically means telecom API contracts with monthly minimums, compliance reviews, number provisioning, and vendor lock-in. You can't just send a single text message without setting up an entire account and billing relationship first.

What Sats4AI Offers

Sats4AI's SMS service gives you two things:

1. Browser SMS — Open the page, enter a phone number and your message, pay a Lightning invoice, and it's delivered as a standard text message. Works on any device with a browser. No SIM card, no phone plan, no app to install.
2. Programmatic access — Send SMS from your code or AI agents via L402 API, MCP server, or OpenClaw. Pay per message with Lightning — no contracts, no API keys to manage, no monthly fees.

Both modes: no account, no credit card, no carrier plan. Messages reach mobile numbers in 200+ countries. The recipient sees a normal text message — no app required on their end.

Who This Is For

Anyone Who Needs to Send a Text Without a Phone Plan

• Traveling abroad — You need to text a local number — a hotel, a driver, a contact — but your carrier charges $0.50 per international SMS or blocks it entirely. With Sats4AI, you send the message from your browser on hotel WiFi for a few sats.
• No phone or SIM card available — You're at a computer and need to reach someone by text right now. Open the page and send. No app to install, no account to create.
• Privacy-sensitive messages — Messages are sent from a service number, not your personal number. No account with your email, name, or phone number. Your identity is never linked to the message.
• Unbanked or no credit card — Many people worldwide have Bitcoin but no access to international credit cards or carrier plans that support international SMS. Lightning opens texting to anyone with sats.

Developers and Businesses Who Need Programmatic SMS

Traditional SMS APIs require contracts, monthly fees, number provisioning, account approval, and compliance paperwork. With Sats4AI, you make a single API call, pay per message with Lightning, and you're done. No vendor lock-in, no recurring charges, no minimum spend.

• Verification codes — Send one-time passwords or confirmation codes to users without signing up for a telecom provider. Pay per message, scale as needed.
• Notification systems — Delivery confirmations, payment receipts, appointment reminders, shipping updates. Any system that needs to reach a phone number via text.
• Alerts and monitoring — Your server goes down, your pipeline fails, a threshold is breached. Fire off a text to the on-call engineer for a few sats. No telecom account needed.
• AI agent pipelines — An AI assistant using the MCP server can generate a response with AI chat, then text it to a phone number — all paid in sats, fully automated.

What It Actually Costs

Pricing starts from 5 sats per message. The exact cost varies by destination country and is shown before you pay — no hidden fees, no minimum balance, no expiring credits. Here's how it compares:

How to Send an SMS

1. Go to sats4ai.com/sms.
2. Enter the destination phone number with country code (e.g., +1 for US, +44 for UK, +81 for Japan).
3. Type your message.
4. Click Send. A Lightning invoice appears as a QR code. The price depends on the destination country.
5. Pay with any Lightning wallet (Phoenix, Alby, Zeus, Wallet of Satoshi, etc.).
6. Your message is delivered immediately after payment confirms.

Automate SMS from Your Code

Three ways to send SMS programmatically, all pay-per-use with Lightning — no contracts, no API keys to manage, no monthly fees:

L402 API

Standard HTTP API with Lightning-native authentication. Send a request, receive a Lightning invoice in a 402 response, pay it, resend with the payment proof, and the SMS is delivered. Works with any language that can make HTTP requests. See the docs.

MCP Server

Connect any MCP-compatible AI agent (Claude, GPT, custom agents) to Sats4AI's tool server. The agent can send SMS messages as part of its workflow — chaining texts with AI chat, transcription, phone calls, and more. The AI handles the payment flow automatically. See the docs.

OpenClaw

Open protocol for AI agents to discover and use tools autonomously. Agents find Sats4AI's SMS service through the registry, negotiate payment, and send messages without human intervention. Learn more.

Combine with Other Sats4AI Services

The real power shows up when you chain services together. Every Sats4AI service works the same way — pay per use with Lightning, no accounts — so they compose naturally:

• SMS + Call — Send a text first, then follow up with a phone call if no response. Multi-channel outreach without any telecom contracts.
• AI Chat + SMS — Generate a response with an AI model, then text it directly to a phone number. Automated customer replies, AI-drafted notifications, or personalized messages at scale.
• TTS + Call + SMS — Generate a voice message, call the recipient to deliver it, then send a text follow-up with a written summary or next steps. Voice-first outreach with text backup.

Why Pay with Bitcoin?

• Instant — Lightning settles in milliseconds. No pending charges, no authorization holds, no billing surprises.
• No gatekeepers — No bank or payment processor can restrict your access. Bitcoin is borderless — works the same from Nigeria, Japan, Brazil, or Germany.
• No commitment — Pay for exactly what you use. No subscriptions, no credit packs, no expiring balances. Use it once and never come back, or use it every day.
• Transparent — The exact price for your destination is shown before you pay. The price is the price.

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