simhook

SimHook turns an Android phone and its SIM into a programmable route for SMS. It suits developers who want software to send texts over a mobile line and handle replies in their own workflows. Its self-hosted edition has no stated limits, but hosted paid plans are not open yet.

Overview

API messages leave through the paired phone’s SIM, while incoming texts can be forwarded to the account as webhooks. This makes SimHook a fit for applications that need two-way SMS tied to a real phone connection, rather than a general-purpose campaign service. The maker explicitly cautions against bulk marketing and texting people who have not opted in; for real volume, it recommends a business SIM.

Key features

Signed webhooks report sent, delivered, and failed states, giving integrations a way to react to delivery outcomes as well as inbound replies. Webhook deliveries are retried for two days, then paused if the endpoint keeps failing. That retry window helps with temporary outages, though a persistently broken endpoint will need fixing before event delivery resumes.

SimHook supports scheduled sends and messages to multiple recipients. The Free plan caps a send at 25 recipients, while Pro allows 500 and Scale 2,500; those higher ceilings suit larger operational notifications, not unsolicited campaigns. Dual-SIM phones are supported, with the SIM selectable for each message, a useful detail for phones with separate lines or routing needs.

API keys can be scoped to sending, reading, devices, or webhooks. A send-only key can submit messages without granting broader access, which is a practical way to reduce what an integration can do if its credentials are exposed. The TypeScript SDK supports Node and edge runtimes, and an MCP server offers eight tools for AI agents, with setup documented for Claude Desktop, Cursor, and Claude Code.

The Android app requires Android 8.0 or newer and is distributed as a signed APK. It updates itself after the user approves installation, so installation and updates depend on accepting APK prompts rather than a standard app-store flow. The full stack can instead be self-hosted from one Compose file under AGPL-3.0; the maker describes that option as free and without limits.

The hosted service runs on Hetzner servers behind Cloudflare and takes nightly database dumps. Firebase Cloud Messaging pushes contain no message content. These are useful operational and privacy details, though they do not change the core dependency on a paired Android phone and SIM.

Pricing

The hosted Free plan costs nothing and allows 30 messages a day, 500 a month, one phone, and 25 recipients per send. It is the only currently usable hosted tier: paid plans are listed as opening soon, and every account remains on Free until then. That makes the current ceiling a material constraint for anyone planning a production workload above those caps.

Pro costs $12 a month, billed at $12 / month or $120 / year. It raises the monthly allowance to 10,000 messages, supports three phones, and permits 500 recipients per send. It is the natural eventual step for a small service or team that needs more capacity than Free but not a larger device pool.

Scale costs $39 a month, billed at $39 / month or $390 / year. It includes 50,000 messages a month, ten phones, and up to 2,500 recipients per send, making it the higher-capacity hosted option. The annual listings—Pro (annual) at $120 a year and Scale (annual) at $390 a year—carry the same respective monthly quotas, phone counts, and send limits as their monthly counterparts.

Self-hosted costs nothing, billed free, and includes the whole stack with no limits of any kind. It is the strongest fit for operators willing to run the stack themselves; hosted convenience is the tradeoff, and the self-hosted option remains subject to its AGPL-3.0 license.

Platforms

SimHook spans Android, API, web, and self-hosted deployment. Android 8.0 or newer is required for the phone app, which acts as the SMS endpoint; the API and web account provide the software-facing side of that connection. It is not a phone-independent SMS API: outbound traffic depends on a paired device and its SIM.

Who it's for

SimHook is best for developers and operators who want SMS integrated into an application or agent workflow, need inbound replies or delivery callbacks, and can manage an Android phone or self-hosted stack. Send-only keys, signed event hooks, and the SDK give integrations useful control points. It is a poor match for unsolicited campaigns, bulk marketing, or teams that need paid hosted capacity immediately.

Pros and cons

• Useful two-way routing: API sends use the paired phone’s SIM, and incoming texts can return by webhook.
• Actionable delivery events: Signed sent, delivered, and failed callbacks support status-aware workflows, with retries for two days.
• Flexible deployment: Self-hosting is free with no stated limits, while the hosted Free tier provides a bounded way to start.
• Hosted capacity is currently constrained: All accounts remain on Free until paid plans open, limiting current use to 30 messages daily and 500 monthly.
• Device and SIM dependency: The service needs a paired Android 8.0+ phone, and the app is installed as an APK.
• Not a campaign platform: The maker advises against bulk marketing and unsolicited texts, and recommends a business SIM for real volume.

Alternatives

For a broader comparison, browse SMS Gateway Software.

Choose SMSBOX if you want an API and web service with a paid model and one-off test credits for sending to your own verified number.

Android SMS Gateway is another Android-and-API option; its free tier is limited to one device and 300 lifetime SMS, while its Starter plan is $19 a month for two devices and unlimited SMS.

Telerivet may suit a reader who wants a freemium Android/API service with 50 messages per day, 50 stored contacts, and two automated services on its Free plan.

OpenVox SMS Gateway is an alternative for readers seeking a Linux or self-hosted API gateway.

Clickatell SMS API is a paid API option with pay-as-you-go outgoing messages, with prices varying by destination and message type.

Bird Verify is for readers focused on verification, where verification is included and channel message charges apply.

Ozeki SMS Gateway is an alternative for readers who need a self-hosted gateway across Android, Linux, web, and Windows.

Smstools offers another freemium option and per-message U.S. SMS pricing without a subscription.

Verdict

Choose SimHook if you need a developer-oriented bridge from an Android SIM to an API, especially when inbound texts, delivery callbacks, or self-hosting matter. Its main advantage is combining phone-based SMS routing with scoped keys and webhook workflows; its main drawback today is that hosted accounts are all confined to Free until paid tiers open. Look elsewhere if your required hosted volume exceeds 500 messages a month now, or if your use case is bulk or unsolicited messaging.