SimLink
Let agents send/receive SMS using your old Android phone
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What is SimLink?
SimLink is a small, self-hostable server that gives an AI agent a real phone number over the Model Context Protocol. It relays texts through an Android phone plus a prepaid SIM you control, so an agent can send and receive SMS through a real mobile number.
The service is designed as a transient relay rather than a message archive. Messages are encrypted in transit, encrypted at rest, never written to logs, and pruned within minutes after delivery.
It exposes MCP tools for SMS workflows, including sending texts, listing recent messages with delivery status, and fetching SMS already on the phone. Fetching messages is two-step and non-blocking, which makes it better suited for agents than a blocking inbox reader.
SimLink is aimed at builders using MCP-capable AI clients such as Claude Desktop, Claude Code, ChatGPT, Cursor, Hermes, and OpenClaw. It can be used through the hosted instance or self-hosted on a VPS, and the project is open source for people who want full control.
SimLink pricing
Pricing model: Freemium
The website says there is no subscription and no per-seat fee. You pay only your normal per-text rate for SMS usage. The hosted instance is available for quick setup, and the full server can be self-hosted on your own VPS for full control. The site does not list tiered paid plans; it emphasizes open source access and usage-based SMS costs.
SimLink pros
- Real phone number for agents
- Works over MCP
- Supports send and receive SMS
- Uses your own prepaid SIM
- Uses an Android phone you control
- Open source codebase
- Hosted instance available
- Self-hosting supported
- No subscription fee
- No per-seat fee
- Messages encrypted in transit
- Messages encrypted at rest
- Messages pruned within minutes
- Message bodies never logged
- Transient relay with no browsable archive
- Non-blocking message fetch flow
- Delivery status for sent messages
- Compatible with many MCP clients
- Can run on your own VPS
- No special hardware purchase needed
SimLink cons
- Requires an Android phone
- Requires a prepaid SIM
- Depends on a real mobile number
- Not a general-purpose messaging platform
- No message history archive
- No long-term inbox browsing
- Self-hosting adds setup complexity
- Hosted service still depends on the operator
- SMS-only focus, not chat app messaging
- Fetch flow is two-step
Frequently asked questions about SimLink
What does SimLink do?
SimLink lets an AI agent send and receive SMS through a real phone number over MCP. It relays messages using an Android phone and a prepaid SIM you control, so the agent can interact with the SMS network like a normal user.
How does SimLink work?
You connect an Android phone with a SIM to the SimLink relay. Your MCP client talks to the relay server, and the server passes messages to and from the phone through the device API and SMS network.
What MCP tools does it provide?
The site lists send_sms for sending a text from the shared SIM, list_messages for recent sent messages and delivery status, and fetch_sms for reading SMS already on the phone.
Does SimLink store message history?
No. The website says it is a transient relay with no browsable archive. Messages are held only long enough to hand them between the agent and phone, then pruned within minutes.
Is SimLink secure?
The site says traffic is encrypted in transit, messages are encrypted at rest, and message bodies are never written to logs. It also states that nothing in the middle stores texts beyond the short relay window.
Can I self-host SimLink?
Yes. The site says the full server can be deployed on your own VPS with Kamal, using your own domain and database, and then pointed to the Android app.
Is there a hosted version?
Yes. The website offers a hosted instance where you create an account and connect a phone in minutes, while the operator runs the server for you.
What does it cost?
The site says there is no subscription and no per-seat fee. The cost is your normal per-text rate, so pricing is tied to SMS usage rather than a software plan.
What do I need to use it?
You need an MCP-capable client, an Android phone, and a prepaid SIM you control. The site says any spare Android in a drawer is enough, and no special hardware purchase is required.
Which clients are supported?
The site says any MCP client works, and it explicitly mentions Claude Desktop, Claude Code, ChatGPT, Cursor, Hermes, and OpenClaw as tested clients with copy-paste guides.