iMessage opt-in links and QR codes

Building on the iMessage API? Build on iMessage with Flow: one agent for iMessage, WhatsApp and Telegram. New to it? Read the iMessage API guide.

The reply-first problem

Without the outbound add-on, a Flow iMessage line replies to people who wrote first. Even with outbound, consent happens in Messages: the customer opts in by texting the line. A checkbox on a website, or consent given on another channel, does not count. For an agent that answers customers, that is a good rule, because it keeps the line from looking like a spammer. It also means somebody has to tap first.

iMessage API rate limits and sending rules explains why lines are protected like this. This post is about the practical side: how to get people to write.

What an opt-in link does

Every Flow iMessage line comes with an opt-in link and a QR code. The link opens Messages with the line’s number filled in and a prefilled text. The person only has to send it, and the conversation exists. In the API, a sender’s address.link is its opt-in link.

You can read it with a live key:

curl "https://api.flow.engineer/v1/senders?channel=imessage" \
  -H "Authorization: Bearer $FLOW_MESSAGING_KEY"

The sender in the answer carries address.link. For comparison, on the Telegram sandbox the link is https://t.me/<bot>?start=<code>, and for WhatsApp it is https://wa.me/.... See Flow’s senders docs.

Where to put it

Anywhere a customer already is and might want to talk:

• Your website. A “Text us” button on product, booking and support pages.
• Receipts and order emails. “Questions about this order? Text us.”
• Confirmation screens after a booking or purchase.
• A QR code on packaging, a table card, a shop window or a printed flyer. A scan opens Messages with the line.
• Email footers and signatures.
• Support pages, next to the phone number.

Make the text on the button say what happens: “Text us on iMessage” beats “Contact”. Put the link behind a button that looks the same on iPhone and everywhere else, and for non-Apple devices offer another channel such as WhatsApp or Telegram. The one-agent guide shows how one handler serves all three.

How Apple Messages for Business does it

Apple’s official business channel works the same way in spirit: the customer starts the conversation. Apple’s FAQ lists these entry points: your website or mobile site, your iOS or iPadOS app, email marketing, QR codes and NFC tags, your Apple Maps listing, a registered business phone number through Message Suggest, and Wallet passes.

That is a different service with its own approval and rules. See Apple Messages for Business vs iMessage API. An opt-in link is for a line from a provider.

Make the first message count

The prefilled text is the first thing your agent receives. Two tips:

• Make it specific. “Hi, I have a question about my order” gives the agent a topic. A blank message does not.
• Tell the agent where it came from. Different links on different pages can carry different prefilled text, so your agent knows the context without asking.

Then greet the person quickly, with typing on, and answer in short bubbles. Tapbacks, typing and effects covers the details that make an agent feel native. Consent rules vary by country and use case, so ask your own lawyer, and honour a stop request at once.

Frequently asked questions

Keep reading

All posts: the Flow blog. The Flow docs have the reference.