Bulk SMS API questions and answers

A bulk SMS API for developers: send one text or a batch of up to 10,000 numbers per request to 227 countries over REST, follow every message with signed webhooks, and pay per message from a prepaid balance. A web console sends campaigns from a pasted list or CSV without code.

Product and engineering teams that send texts from their own systems: login and sign-up codes, order and delivery updates, appointment reminders, payment alerts, service notices and marketing campaigns. Anyone who can make an HTTPS request can use it.

227 countries and territories, listed with their prices on the pricing page and the countries pages. One request can mix countries: every number is priced by the country it belongs to.

No. You pay per message segment from a prepaid balance, and there is no monthly fee, setup fee or minimum volume. The balance has no expiry date.

Accounts start with a zero balance and the first top-up opens everything. The first top-up adds a bonus of up to 40%, so the first messages cost less. Prices are public, and the estimate endpoint and the console show the exact cost before anything is sent.

POST /v1/batches takes up to 10,000 numbers per request, either one text for everyone or a personal text per number. The console takes 50,000 numbers per campaign. Larger lists are split into several requests.

The queue runs every two seconds and hands up to 1,200 messages per minute per account to the network, in the order they were accepted. A single message usually leaves within a few seconds of the request.

International E.164: a plus sign, the calling code and the national number, such as +14155550123. Spaces, dashes, brackets and a 00 prefix are cleaned automatically; duplicates and numbers that cannot be read are set aside and not charged.

Up to 10 segments: 1,530 characters in GSM-7 or 670 in Unicode. One segment holds 160 GSM-7 or 70 Unicode characters; longer texts are split into parts of 153 or 67 characters and joined again on the phone.

One character outside the GSM-7 alphabet, such as a curly quote, an emoji or a letter like á or ç, switches the whole text to Unicode at 70 characters per segment. The console composer names those characters, and POST /v1/estimates returns the encoding before you send.

Yes. Add send_at to an API request, or pick a time in the console, from 2 minutes to 45 days ahead. A scheduled batch can be canceled until it starts, and its full cost returns to the balance.

Yes. Through the API, send a batch with messages, one {to, text} per recipient. In the console, paste or upload a list with extra columns and use merge fields {{1}} to {{9}} in the text.

Set your opt-out wording once in Settings, for example a link or an email address, and the console adds it to campaign texts when you tick the box. Through the API you control the full text, so add the line yourself to marketing messages. Numbers on your do-not-send list are skipped by the console and the API, and not charged.

Yes. The console has a test send to one number before a campaign, and through the API you can send a single message to your own phone with POST /v1/messages.

Each message moves from queued to sent to delivered or failed. Add a webhook URL in the console to get a signed event for every final status, or read GET /v1/messages/{id} and GET /v1/batches/{id}.

In the Standard Webhooks format: headers webhook-id, webhook-timestamp and webhook-signature, where the signature is HMAC-SHA256 of id, timestamp and raw body with your whsec_ secret. The docs have verification code for Node.js, Python, PHP and Go.

Every event gets 10 attempts over about 24 hours, and every attempt is listed in the console with its HTTP status. You can also poll the message endpoints at any time.

The handset may be switched off for too long, the number may no longer be in service, or the network may refuse the message. The failed status carries an error code, and the price is refunded.

Batches, messages and the balance ledger stay in your account and in the API. The request log keeps your last 500 API calls and the webhook log your last 500 deliveries.

Yes. In the console, paste numbers or upload a CSV file of up to 50,000 rows, write the text with merge fields, check the preview for each recipient and the cost per country, and send now or at a set time.

Balance, recent batches with live counts, each batch with its messages and statuses, top-ups and the ledger, API keys, webhook settings and deliveries, the request log, the price list, support tickets and settings.

From the Support page of the console. Payment questions can be asked from the first day; the other topics open after the first top-up is credited.