Show HN: Let agents send/receive SMS using your old Android phone

SimLink by Snáz.cz is an open-source, self-hostable server that gives AI agents a real phone number by relaying SMS through an old Android phone and a prepaid SIM card via the Model Context Protocol. The service encrypts messages in transit, never logs them, and prunes data within minutes, offering a transient relay with no subscription fees.

SimLink by Snáz.cz / sms · mcp · your sim SMS for your agents, over MCP . A small, self-hostable server that gives an AI agent a real phone number. It relays texts through an old Android phone and a prepaid SIM you control — send and receive over the Model Context Protocol. I built it for my own agents and put it here in case it's useful to you. It's open source. bash point any MCP client at the endpoint $ https://simlink.snaz.cz/mcp Authorization: Bearer <token or, for clients that only accept a URL $ https://simlink.snaz.cz/mcp/<token get a token → install the app, sign in, share a SIM how it works Nothing in the middle stores your texts. The server holds a message only long enough to hand it from the agent to the phone or back — encrypted, never logged, pruned within minutes. mcp tools send sms to, body Send a text from the SIM the user shared with you. list messages since?, limit? Recently sent messages, with delivery status and any error. fetch sms box?, since?, address?, limit?, request id? Read SMS already on the phone inbox/sent . Two-step and non-blocking: start a read, then call again with the returned request id to collect the rows. Args marked ? are optional. Full machine-readable summary at /llms.txt /llms.txt . properties - transit - TLS between phone, server, and agent. - at rest - Encrypted in the database; pruned within minutes. - logs - Message bodies are never written to logs. - history - None — a transient relay, no browsable archive. - number - A real SIM number, not a shortcode that gets flagged. - hardware - Any spare Android in a drawer + a prepaid SIM. Nothing to buy. - cost - Your normal per-text rate. No subscription, no per-seat fee. - source - Open source — audit it, or run the whole thing yourself. run the server Use this instance Create an account here and connect a phone in minutes — I run the server. Messages are encrypted in transit, never logged, and pruned within minutes. create an account /registration/new Run it on your VPS It's open source. Deploy the whole SimLink server yourself with Kamal — your domain, your database — then point the Android app at it. read the source https://github.com/LukBrezina/simlink tested clients Any MCP client works — these just have copy-paste guides. Building an agent? Point it at https://simlink.snaz.cz/mcp