SimGate FAQ — SMS API & Android SMS gateway

SimGate turns an Android phone into a private SMS gateway. You install the SimGate Gateway app, connect your device, and then send and receive text messages through your own SIM card using a simple REST API. Instead of buying numbers and paying per message from a traditional provider, you send SMS from your own number at a flat monthly price.

The SimGate Gateway app runs on an Android phone that stays online and keeps its SIM active. When your backend calls the SimGate API, the request is routed to your connected device, which sends the SMS through its normal carrier connection — the same way it would send any text. Inbound messages received on the SIM are captured by the app and forwarded to your webhook, so the phone becomes programmable infrastructure you fully control.

SimGate is built for developers, indie hackers, and small teams who want to send SMS from their own number without per-message CPaaS fees. It's a good fit for OTP and 2FA codes, server and uptime alerts, appointment reminders, two-way conversations, and low-volume notification workloads where a flat monthly price beats metered pricing.

Create a free account, install the SimGate Gateway app on an Android phone, and connect the device by scanning the pairing QR code from your dashboard. Generate an API key, then make your first API call to send a test SMS. Most people are up and running in a few minutes without buying a number or approving a campaign.

You need an Android phone with an active SIM, a data or Wi-Fi connection to keep the device online, and the SimGate Gateway app installed. A spare or dedicated Android device works well as an always-on gateway. No SIM contracts with an SMS provider, no number provisioning, and no server hardware are required.

No. Developers can call the REST API directly, but you can also send and receive SMS without writing code by wiring SimGate into no-code automation tools such as n8n, Make, Zapier, Pipedream, and Node-RED using a single HTTP step.

SimGate uses flat monthly pricing instead of charging per message. The Free plan includes 250 SMS per month so you can test in production, and paid plans add higher monthly volumes, unlimited daily sending, and more connected devices. You pay the same predictable amount whether you send 10 messages or your full monthly allowance.

Yes. The Free plan lets you connect one device and send up to 250 SMS per month with a daily cap, which is enough to build and validate an integration end to end. You can upgrade at any time when you need more volume or additional devices.

No. Because messages are sent through your own SIM, there is no per-message SimGate surcharge. Your carrier's plan covers the actual texts, and SimGate charges a flat monthly subscription for gateway access, the API, inbound webhooks, and automation. This is the core reason SimGate is cheaper than metered providers for steady workloads.

Send a POST request to the SimGate send endpoint with your API key, the device ID to send from, the recipient phone number in E.164 format, and the message text. The connected phone delivers the SMS through its SIM and returns a status you can track. It's a single, plain HTTP request that drops into any language or framework.

An API key authenticates your requests to SimGate. You generate keys from your dashboard and pass one in the x-api-key header on every call. You can create multiple keys for different apps or environments and revoke any key instantly if it's exposed.

Yes, within your plan's daily and monthly limits and your carrier's fair-use policy. SimGate is designed for legitimate transactional and notification volume from your own number rather than unsolicited mass marketing. For steady bulk notification workloads, the flat monthly price is far more predictable than per-message billing.

Yes. SimGate is a two-way SMS gateway. Any text delivered to your SIM is captured by the app and can be forwarded to your server as an inbound webhook, so you can build replies, keyword handling, and full conversations on your own number.

When a message arrives, SimGate sends an HTTP POST to the webhook URL you configure, containing the sender, the text, the receiving device, and a timestamp. Your backend can respond however you like — log it, trigger a workflow, or send an automatic reply from the same SIM.

Yes. SimGate's automation rules let you match inbound messages by text content, sender, or device, then automatically send a reply, call your webhook, and record the result in the automation logs. This makes it easy to build keyword responders and opt-in/opt-out flows without a separate workflow tool.

Because SimGate is a plain REST API, it works with any tool that can make an HTTP request. There are ready-made guides for n8n, Make (Integromat), Zapier, Pipedream, Node-RED, Home Assistant, and Uptime Kuma, so you can send and receive SMS from the automations you already run.

Yes. Tools like Uptime Kuma and Home Assistant can call SimGate on an event to text you from your own number when a server goes down, a sensor trips, or a threshold is crossed. It's a reliable, low-cost way to get real SMS alerts without a paid alerting add-on.

Yes. Add an HTTP/webhook step in Zapier, Make, or Pipedream that posts to the SimGate send endpoint with your API key, and any Zap or scenario can send SMS from your SIM. You can also point SimGate's inbound webhook at these tools to kick off automations when a text arrives.

It depends on your plan: the Free plan supports one device, and paid plans allow multiple connected phones, up to unlimited on the top tier. Running more than one device lets you spread volume across SIMs and add redundancy so sending continues if one phone drops offline.

A message can only be sent while the device that owns the SIM is online, so the gateway phone should stay powered, connected, and awake. SimGate surfaces device status through the dashboard and API so you can monitor connectivity, and connecting more than one device gives you a fallback if a phone loses power or signal.

SimGate is well suited to transactional and notification traffic when you follow a few production practices: use a dedicated always-on device, keep it charging with the app whitelisted from battery optimization, monitor device status, and add a second device for redundancy. Our production checklist walks through each step.

Messages are sent and received on your own SIM and your own device, so they don't pass through a third-party carrier's messaging platform the way they do with traditional SMS APIs. This keeps you in control of your number and reduces how many parties can see your message content.

Yes. Recipients see texts coming from the number on the SIM in your gateway phone, not a shared shortcode or rented number. That improves trust and reply rates, and it means two-way conversations happen on a number your contacts recognize.

Because the SIM and hardware are yours, message content originates and terminates on infrastructure you own rather than a provider's cloud. If keeping SMS data on your own infrastructure is a requirement — for compliance or privacy reasons — a self-hosted-style gateway model like SimGate is designed for exactly that.

Yes. SimGate is an alternative to Twilio and other CPaaS providers for teams that would rather send from their own SIM at a flat monthly price than pay per message and per number. There's no number provisioning or campaign registration, and your texts come from a number your recipients recognize.

SimGate takes a fundamentally different approach from Vonage, MessageBird, Sinch, Bandwidth, and Infobip: instead of routing through a provider's network and billing per message, it sends through your own SIM for a predictable monthly fee. For lower-volume, own-number sending, that usually means simpler setup and lower total cost.

If you need to send very high volumes across many countries instantly, guaranteed carrier-grade throughput, or features like number pools and A2P short codes, a large CPaaS platform may fit better. SimGate shines for own-number, flat-price sending at low to moderate volume — the case where per-message pricing hurts most.

Sending SMS from your own SIM is legal when you have consent to message the recipient and you follow the applicable regulations in your region (such as obtaining opt-in and honoring opt-out requests). SimGate is intended for legitimate transactional, notification, and conversational messaging — not unsolicited spam.

Yes. Each plan has a monthly SMS allowance and, on lower tiers, a daily cap; higher tiers remove the daily cap. Your mobile carrier also enforces its own fair-use limits on a consumer SIM, so SimGate is best matched to steady transactional and notification volume rather than aggressive mass campaigns.

Yes — one-time passwords and 2FA codes are one of the most common SimGate use cases. Because codes send from your own recognizable number, they arrive reliably for the recipients your SIM can reach, which works well for login verification and account security flows at low to moderate volume.