Getting started

This guide takes you from a new account to your first message, and explains the handful of ideas everything else on our platform is built on. When you're ready for exact requests and responses, the API Reference has every endpoint.

1. Create your account and API key

1. Sign up or log in at app.sintalk.com.br.
2. Create an API key from the dashboard. Give it only the permissions your integration needs, and keep it on your server: anyone holding the key can send messages, and be billed for them, on your account.

Every request to the API is authenticated with that key. The API Reference shows how to pass it, and lets you try requests with it right from the browser.

2. Core concepts

Messages. A message is one piece of content sent to one phone number over one channel: RCS, SMS, or Voice. You can send the same content to many recipients in a single request, and each recipient gets their own message, with its own delivery status and its own charge. Content can be personalised per recipient, such as a name, a code, or an order number.

Templates. A template is saved, reusable message content for a channel. Instead of repeating the content on every send, you reference the template and supply each recipient's personalised values. A template can also carry follow-ups, such as sending an SMS version when an RCS message is not delivered.

Contacts and contact lists. A contact is a person on your account, identified by their phone number, so their history is tracked across channels. Contact lists group contacts for sending. Lists come in two types: default lists, which campaigns send to, and blacklist lists, which suppress sends on the channels they cover. A message to a blacklisted contact is marked blocked, never handed to a carrier, and not charged.

Campaigns. A campaign sends one template to every contact in a list, now or at a scheduled time. Every message it creates is attributed to the campaign, so deliveries and results roll up in one place.

Webhooks. Sending is asynchronous: a successful request means your messages were accepted, not that they were delivered. Each message starts as pending and moves through sending and sent to a final status: delivered, not delivered, error or blocked. We notify the webhook endpoints you register when it reaches sent and when it reaches its final status. Use webhooks rather than polling to keep your systems up to date.

Files and inbound messages. Media for RCS cards and audio for Voice can be uploaded as files. Replies and RCS events your recipients send back arrive as inbound messages.

3. Choose a channel

For most use cases, send RCS first and fall back to SMS. Read more:

• RCS vs SMS: why RCS converts better
• SMS character counts and segments: how Portuguese accents and emoji change what an SMS costs.

4. A typical first integration

1. Register a webhook endpoint on your server, so you receive status updates from the first message on. Verify each delivery's signature, and handle duplicates, since the same update can be delivered more than once.
2. Create a template for your first use case, for example an order confirmation, with placeholders for the values that change per customer.
3. Send to yourself. Send the template to your own phone number and watch the status updates arrive at your webhook.
4. Make sends safe to retry. Attach an idempotency key to each send, so a timeout or network error never sends or charges twice.
5. Go live. Send from your application as events happen, or load contacts into a list and run a campaign.

Phone numbers are Brazilian mobiles. We accept common formats and normalise them to the international E.164 form (+55, area code, number).

5. Next steps

• API Reference: authentication, every endpoint, and a request console you can use with your key.
• Send messages: the endpoint behind every send.
• Create a template and Create a webhook endpoint.
• Questions? Write to [email protected].