Tutorial sulla costruzione della Signal House: AI Agenti con API SMS e voce

Signal House is an SMS and voice API for developers building AI agents that communicate beyond a chat window. Its SDK, inbound webhooks, delivery logs and programmable calling support appointment assistants, customer service agents and account updates.

A useful agent must do more than write a convincing reply. Your software needs to send that reply, receive an answer, recognise delivery failures and know when a person should take over.

Signal House supplies messaging and calling infrastructure while your application controls model selection, memory and business rules. Its integration path suits AI coding tools, so you can build around conversations instead of treating telecom setup as a separate engineering project.

AI Native Starts Inside Your Coding Workflow

In precedenza communications API workflows typically started with reference pages, manual endpoint wiring and callback configuration. Signal House approaches integration through AI assisted development, including a setup path for Cursor and Lovable. Developers can ask a coding assistant to inspect its SDK and implement a messaging feature against actual method signatures.

The distinction is not that established communications platforms cannot support agents. A better question is how much integration context your strumento di codifica receives before producing code.

Signal House’s SDK package includes an agents.skills entry and bundled instructions covering setup, SMS, webhooks, numbers and 10DLC. Those are concrete building blocks behind AI native communications infrastructure, not just a slogan.

Developer task	Signal House component	Your application’s responsibility
Send customer messages	SDK di messaggistica	Approve recipients and content
React to replies	Inbound webhooks	Retrieve conversation context
Separate customer projects	Sub Groups	Enforce tenant permissions
Add telephone interactions	API vocale	Choose conversation and handoff logic

Sub Groups organise numbers, brands and campaigns by customer or use case. Do not treat an organisational group as a replacement for application authorisation. Keep ownership checks beside every messaging tool your model can invoke.

Add Programmable Voice Without Confusing Calls With Conversation

Signal House supports backend initiated calls, browser calling and SHML call control. SHML uses XML responses to instruct a call to speak text, play audio, collect keypad input, record audio or connect another number.

For a backend call, install the SDK above and use an ES module. Set the four environment variables referenced below. The sender must be your voice enabled number; ANSWER_URL must be an HTTPS endpoint that returns your call instructions.

import { SignalHouseSDK } from "@signalhousellc/sdk";
const required = ["SH_API_KEY", "CALL_FROM", "CALL_TO", "ANSWER_URL"];
for (const name of required) {
  if (!process.env[name]) throw new Error(`Missing ${name}`);
}
const client = new SignalHouseSDK({
  apiKey: process.env.SH_API_KEY,
  baseUrl: "https://v2.signalhouse.io",
});
try {
  const { data } = await client.voice.calls.create({
    callData: {
      from: process.env.CALL_FROM,
      to: process.env.CALL_TO,
      answer_url: process.env.ANSWER_URL,
    },
  });
  console.log({ callId: data.call_id, status: data.status });
} catch (error) {
  console.error("Call request failed", {
    status: error?.response?.status ?? "unknown",
  });
  process.exitCode = 1;
}

This example initiates a call; it does not implement a live speech agent. Add destination authorisation before exposing it through an application endpoint.

Inbound calls need a programmable voice profile. Set routeAction to CALL_CONTROL, point webhookUrl at your handler and assign the number. Callbacks include CallSid, From, To and CallStatus. Save the call identifier beside your conversation record so a subsequent SMS confirmation belongs to the same customer task.

For browser calling, install jssip alongside the SDK. Your server issues a temporary voice token, and the browser uses Device from @signalhousellc/sdk/voice-browser to register and connect. Authenticate your token endpoint and keep permanent credentials on the server.

Live conversation needs more than call initiation. Confirm a compatible audio connection, riconoscimento vocale, response audio and interruption handling before choosing a voice model stack. SHML keypad collection is not proof of bidirectional model audio streaming. A documented media integration must settle that decision.

Begin with a bounded reminder or human transfer. Add live conversational speech only after that connection is verified.

Delivery Receipts Should Drive Your Agent’s Next Move

Signal House Message Logs expose message identifiers, segment counts, cost, carrier responses and delivery progress. Use those records to separate API acceptance from handset delivery.

Message state	Significato	Suggested application action
Creato	Accepted into Signal House	Save the message identifier
Enqueued	Waiting for dispatch	Keep delivery pending
Dequeued	Removed from the queue	Continue awaiting carrier progress
Inviati	Passed onward for delivery	Do not mark as delivered
consegnato	Delivery receipt received	Update transport outcome
fallito	Error recorded	Classify before retrying

A delivered message is not evidence that a customer read or understood its contents. Keep business outcomes, such as “appointment accepted”, separate from transport states.

An absent receipt should not automatically trigger a second SMS or a phone call. Set an explicit waiting policy and escalation path in your application.

Price Agent Conversations by Segments, Not Replies

Signal House’s 2026 entry local 10DLC SMS rate is $0.0065 per outbound segment, before carrier charges. AT&T adds $0.0035; Verizon and T-Mobile each add $0.0045. Higher volume tiers reduce platform rates.

Componente di costo	Entry charge
Local outbound SMS	$ 0.0065 per segmento
Toll free outbound SMS	$ 0.0079 per segmento
Verifica del marchio	$4.50 per verification attempt
Registrazione della campagna	$ 15 una volta
Low volume campaign	$ 1.50 al mese
Campagna standard	$ 10 al mese

Carrier fees, number charges and any additional services sit outside those messaging base rates. Confirm account specific MMS, number renewal and voice charges before funding production traffic.

Consider 10,000 outbound single segment local messages, all charged a $0.0045 carrier fee. Platform charges total $65 and carrier charges total $45, producing $110 before numbers, registration, traffico in entrata, voice and model costs. That is an example calculation, not a complete quote.

Now add model verbosity. GSM 7 messages fit 160 encoding units in one segment, or 153 per part once concatenated. UCS 2 messages allow 70 in one segment and 67 per concatenated part. Unicode content can therefore change costs sharply.

Misura SMS segment based pricing before dispatch, using an encoding aware counter. Give your agent a length budget and send detailed material through an approved link when appropriate.

A shorter response is not merely a cleaner copy. At scale, it can reduce both billed segments and pressure on sending allowances.

Keep Throughput and Human Handoff Under Control

Campaign choice affects capacity. Signal House’s low volume mixed option permits up to 6,000 daily segments overall, including a 2,000 daily T-Mobile limit. A low volume campaign cannot simply become a standard campaign; a new registration is required.

Build queues around approved carrier, brand and campaign allowances rather than a guessed universal requests per second limit. A burst of model responses should create queued work, not uncontrolled send attempts.

Before broader release, require three observable checks:

Plan the handoff as carefully as booking. Set conversation ownership to human before starting transfer, cancel queued automated messages and expose previous SMS context in the operator interface. Release ownership only through an explicit action.

Maintain a shared conversation record across SMS and voice. Include pending appointments, previous contact attempts and current ownership, but restrict sensitive content to roles that need access.

Measure completed customer tasks alongside cost per conversation. Send counts alone reward activity, not useful outcomes.

Build the Communications Layer Your Agent Can Actually Use

An agent built to contact customers needs more than a capable model. Signal House gives developers a practical route from generated text to SMS exchanges and programmable calls, supported by SDK context, webhooks and delivery visibility.

Start with one approved workflow. Connect a number, prove replies, constrain model actions and inspect costs before adding complexity. Let working results, rather than impressive promises, decide when to scale.

Se stai costruendo un AI agent that needs SMS or voice, build its communications layer on Signal House. Keep intelligence in your application and make every customer interaction accountable.