Sponsored Produced in partnership with Signal House.
AI agents are moving off the screen. They book appointments, qualify leads, send confirmations, run two-factor codes, follow up with customers, and increasingly place and take calls, and a growing share of that runs over SMS and voice. The moment an agent has to reach a real phone, it needs a communications layer underneath it: numbers, carrier connections, delivery, and the compliance paperwork that keeps messages from being filtered as spam.
Signal House is built for that layer. It is a communications API aimed at developers wiring SMS and voice into AI agents and automations, not the enterprise phone room.
What Signal House is
Signal House is a Tier-2 messaging and voice aggregator: it sits between your application and the mobile carriers, so you work with one API and one account instead of stitching together separate carrier deals.
The big communications APIs, Twilio chief among them, were built for an earlier era of software, when a developer wired messaging into a web app by hand. Signal House is built for how software gets made now, where an agent or an automation has to message and call on its own. It competes with Twilio, Plivo, Vonage, and Sinch on price, approval speed, and support.
Signal House covers the channels an agent needs from one API: SMS, MMS, and group messaging, plus voice, toll-free, and short code, with the A2P 10DLC registration US carriers require handled in-platform. So an agent can text a confirmation and place the follow-up call on the same account, without wiring up a second provider for voice.
What matters when you wire it into an agent
A handful of things decide whether a messaging provider is worth committing to. The first is how quickly you can start sending: every US campaign has to clear A2P 10DLC registration before a message goes out, and Signal House turns standard campaigns around in about 48 hours, against the several business days Twilio can take. Carrier and registry vetting can still add time on either, since that step is out of any provider’s hands. The second is whether messages arrive at all, and Signal House runs above 95% deliverability on 10DLC, the floor you need for the reminders and one-time codes an agent leans on.
The build itself is straightforward: REST APIs, SDKs, sandboxes, and low or no-code tooling, with docs covering endpoints, formats, and error codes, plus HubSpot and GoHighLevel integrations that shorten the path for a CRM-driven agent. Support is included on every plan rather than sold as an add-on, and it is what customers raise most: on G2 it holds around 4.6 out of 5, and the reason buyers most often give for moving is being able to reach a real person.
How pricing works
Signal House’s list pricing is public. Rates are per outbound message segment, before separate carrier fees, and step down with volume:
| What | Entry rate | At high volume |
|---|---|---|
| SMS (10DLC) | $0.0065 / segment | $0.0030 at 10M+/mo |
| MMS | $0.0200 / message | $0.0170 at 500k+/mo |
| 10DLC local number | $1.00 / mo | $0.25 / mo at volume |
| A2P registration | Brand $4.50; campaign $15 one-time | Standard campaign $10/mo |
Carrier pass-through fees (for example AT&T, Verizon, and T-Mobile surcharges) are billed separately, as they are with every US aggregator. Voice and short-code are priced on request.
If you are coming from Twilio
Most teams weighing Signal House are coming off Twilio, so it helps to be clear about the trade. On price, Signal House is the cheaper option, and on high-volume messaging the gap can be large, though how large depends on your volume, destinations, and message mix, so price it against your own traffic rather than a headline percentage.
Past price, the real difference is setup and support: Signal House bundles hands-on support into every plan rather than selling it separately, and approves 10DLC campaigns faster. Twilio’s edge is the flip side of being the incumbent. It has a broader catalogue (video, email, and a huge partner ecosystem) and the deepest documentation in the market. If your agent will soon need channels beyond messaging and voice, or you want the most battle-tested option, that breadth is worth weighing.
Who it is for, and who it is not
Signal House is a strong fit if you are a developer or a small team adding SMS and voice to an AI agent, an automation, or a CRM; you send a lot to US numbers and want the per-message cost down; and you would rather have published pricing and a real person on support than a giant feature catalogue.
It is a weaker fit if you send mainly outside the US, or if you need a regulated setup such as a signed agreement for handling protected health data, which the site does not currently advertise. In those cases, check scope with their team first.
See how Signal House fits AI agents →Frequently asked questions
Is Signal House a Twilio alternative?
For messaging and voice, yes: a lower-cost, faster-to-approve substitute for Twilio, built with AI-agent and automation workloads in mind. Twilio still has a broader catalogue (video, email, a larger partner ecosystem), but for the SMS, voice, and messaging an agent needs, Signal House covers it for less.
Does Signal House support voice?
Yes. Signal House offers voice alongside SMS, MMS, and group messaging, so an agent can both text and call through a single API and account.
How fast is A2P 10DLC approval?
Standard campaigns are reviewed in about 48 hours. Actual times also depend on the Campaign Registry and carrier vetting, which sit outside any provider’s control.
How much does Signal House cost?
List prices start at $0.0065 per SMS segment on 10DLC, dropping to $0.0030 at very high volume, with MMS from $0.0200. Carrier pass-through fees are billed separately. See the pricing table above.
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