Ozeki SMS Gateway vs simhook

Ozeki SMS Gateway is on-premises software for businesses that send SMS from an office, automate messaging, or provide SMS services to customers. It sends and receives messages through modems, Android phones, and protocols including SMPP, UCP/EMI, CIMD2, OZX, HTTP/REST, SIP, and Modbus/SNMP. Routing options include least-cost and backup routing, load balancing, copying, and modifying messages. Applications can connect through REST, SOAP, JSON, WebSocket, SDKs, SQL polling, and integrations such as databases, Excel, email, FTP, and text files. The gateway can run on physical or virtual servers, cloud platforms, or an Android phone. Listed security controls include HTTPS, TLS/SSL for supported protocols, encrypted password storage, and logs that can hide phone numbers and message text. A free trial is available, but there is no free plan. Licenses are one-time purchases; listed plans range from €1,490, paid once to €79,990, paid once. SMS provider charges may also apply.

SimHook turns an Android phone with a SIM into an SMS gateway and API for sending and receiving texts. API messages travel through the paired phone, while incoming texts can be forwarded as webhooks. Signed webhooks report sent, delivered, and failed status changes; they are retried for two days and paused if an endpoint keeps failing. The service also supports scheduled sends, multiple recipients, and dual-SIM phones, with a SIM selectable for each message. Its TypeScript SDK supports Node and edge runtimes, and an MCP server provides eight tools for AI agents. API keys can be limited by scope, including a send-only option. The Android app requires Android 8.0 or newer and is distributed as a signed APK. The full stack can be self-hosted from one Compose file under AGPL-3.0, which the maker says is free without limits. Hosted accounts are currently on Free; listed paid plans open soon. The maker says the service is not for bulk marketing or unsolicited texts.