Announcing the removal of the legacy Mobipost, DirectSMS, SMS Broadcast and Streetdata APIs

On 29 October 2027, Sinch Engage will permanently switch off the legacy Mobipost, DirectSMS, SMS Broadcast and Streetdata APIs. If your website, software or system sends or receives messages through one of these APIs, you'll need to move it to the Sinch Engage REST API before then. After the switch-off, requests to the legacy APIs will fail and your messages won't be sent.

Nothing else about your account is changing. You'll keep the same account, numbers and pricing. Only the way your system connects to us is changing.

The Sinch Engage REST API is our modern, secure and scalable messaging API that we continue to develop and enhance with new features. We recommend all Sinch Engage customers use the REST API.

This announcement covers:

• What's happening?
• Why is Sinch making this change?
• What do I need to do?
• I use software from another company. What do I need to do?
• How can I tell which accounts, keys or applications are affected?
• What happens if I don't migrate before the deadline?
• Frequently asked questions
• Getting help

What's happening?

We're retiring the legacy APIs in three stages.

Stage 1 (from 30 October 2026): Announcement

The legacy APIs keep working as normal. You can create a REST API key and start migrating straight away.

Stage 2 (from 31 March 2027): No new legacy credentials

You can no longer create new Legacy API Credentials. Existing legacy credentials keep working until the switch-off.

Stage 3 (After 29 October 2027): Switch-off

The legacy APIs are switched off permanently. Every request to them will fail, and they can't be switched back on.

Which APIs are affected?

What isn't affected?

• Your account, users, numbers and pricing
• Sending and receiving messages in the web app at https://app.sinch.com
• Webhooks set up under Settings → API Settings → Webhooks

Why is Sinch making this change?

The Mobipost, DirectSMS, SMS Broadcast and Streetdata APIs were each built separately, on their own systems, before they became part of Sinch. Some of the technology behind them is reaching the end of its life. We've kept them running for as long as we can, but maintaining several separate APIs means we can only keep them going, not make them better.

Your account already runs on the Sinch Engage platform. Moving your integration to our REST API brings it onto the same platform, where our ongoing work on security, reliability and performance happens. It keeps your integration up to date, your account safe, and your messages flowing. We think it's the best path for you.

With the REST API you get:

• Ongoing security and performance updates. The REST API runs on our main platform, which we monitor, maintain and improve continuously.
• New features as they're released. Improvements to the REST API are available to you straight away.
• Easier API management. Create and manage your own API keys in Settings → API Settings.
• Reporting built in. Messages you send through the REST API appear in Sinch Engage reporting alongside everything else.
• Real-time delivery reports and replies. Webhooks send them to your system as they happen, in a format you choose.
• Your own references on every message. Add metadata, such as a booking or customer ID, and get it back with delivery reports and replies.
• Clear responses. Every message gets its own ID, and detailed errors tell you exactly which message and field needs fixing.
• Up-to-date documentation. The REST API documentation covers every endpoint, and includes instructions made for AI coding assistants.

What do I need to do?

1. Find your integrations

Work out which websites, systems, scripts or plugins use your legacy API credentials. See How can I tell which accounts, keys or applications are affected? below.

2. Create a REST API key

Everyone migrating needs a new key. Your legacy credentials won't work with the REST API.

1. Log in at https://app.sinch.com.
2. Go to Settings → API Settings.
3. In the Basic Authentication section, click Create new key.
4. Copy your API key and API secret straight away and store them somewhere safe. The secret is only shown once. If you lose it, you'll need to create a new key.

Don't use the Create new key button under Legacy API Credentials. Those credentials only work with the legacy APIs.

3. Update your integration

Follow the migration guide for your integration. Each guide shows your old API calls side by side with the REST API equivalent.

• Mobipost migration guide
• DirectSMS migration guide
• SMS Broadcast migration guide
• Streetdata migration guide

Whichever API you're moving from, make sure that:

• your system supports TLS 1.2 minimum. TLS 1.3 is recommended.
• phone numbers are in E.164 international format, for example +61412345678
• requests are sent as JSON

4. Set up delivery reports and replies

If you already have webhooks, you'll find them under Settings → API Settings → Webhooks and they'll keep working. 

If you don't have webhooks, we recommend creating one. See Webhooks Management for the options.

5. Test and switch over

Your legacy credentials and your REST API key work side by side on the same account until the switch-off.

• Keep both running for important messages. For anything your business can't afford to stop sending, such as reminders or verification codes, keep your legacy credentials active until your REST API integration is working. Then switch over.
• Only collect delivery reports and replies in one place. Both APIs use the same account, so they can see each other's messages. If two systems check for delivery reports or replies at the same time, one may miss them or both may process them. Use webhooks, or check from one system only.
• Don't delete your legacy credentials early. From 31 March 2027, you can't create new ones.

Once everything has moved, stop using your legacy credentials.

I use software from another company. What do I need to do?

Many customers send messages through software made by another company, such as a CRM, booking system or website plugin. If that software connects to us through one of the legacy APIs, your software provider needs to update it to use the Sinch Engage REST API.

You can't make this change yourself, because it's part of your provider's software. But there are a few things you can do to keep your messages sending.

Sinch is separately reaching out to our software partners to also make them aware of this upcoming change.

1. Talk to your software provider

Contact your provider and ask:

• whether their software uses one of the APIs listed in Which APIs are affected?
• when they'll release an update that uses the Sinch Engage REST API
• what you'll need to do to switch over

You can share this announcement with them. We're also contacting software providers we have partnered with and know are using these APIs. 

2. Create a REST API key when your provider is ready

Unless your provider tells you otherwise, you'll need to create a new REST API key and enter it in their software once their update is ready.

1. Follow the steps in Create a REST API key above.
2. Enter your API key and API secret in your software, following your provider's instructions.

The secret is only shown once, so have your software open and ready before you create the key.

3. Keep your legacy credentials until the update is working

Don't delete your Legacy API Credentials until messages are sending through the updated software. From 31 March 2027, you can't create new ones.

What if my provider can't update in time?

If your provider can't update their software before 29 October 2027, or you can't reach them, contact our Support team as early as you can. We'll talk you through your options, such as sending from the Sinch Engage web app or moving to software that already uses the REST API.

Our Support team can also help you create your REST API key, and check whether your account is still sending messages through a legacy API.

How can I tell which accounts, keys or applications are affected?

You're affected if anything connects to one of the APIs listed in Which APIs are affected? Check for these signs:

• Legacy credentials in your account. In Settings → API Settings, you have credentials listed under Legacy API Credentials.
• Old web addresses in your code or settings. Your system sends requests to a Mobipost, DirectSMS, SMS Broadcast or Streetdata web address, rather than https://au.app.api.sinch.com.
• A plugin or third-party app. You connect another product (for example a CRM, booking system or website plugin) to your account using your legacy username and password or API credentials.
• An email from us. We're emailing the admins, owners and developer contacts of every affected account.

If you have more than one account, check each one.

Not sure? Contact our Support team. They can check whether your account is still sending messages through a legacy API.

What happens if I don't migrate before the deadline?

From 29 October 2027:

• Every request to a legacy API will fail, and messages won't be sent.
• You won't be able to collect delivery reports or replies through a legacy API.
• Automated messages, such as appointment reminders, alerts or verification codes you might be sending via this API, will stop. If your system doesn't check for errors, this may happen without you noticing.

We are unable to offer extensions. The legacy APIs will be switched off for all customers at the same time.

Frequently asked questions

What happens on each key date?

Is my Mobipost, DirectSMS, SMS Broadcast or Streetdata account going away?

No. Your account, numbers and pricing stay the same. Only the API your system uses to connect is changing.

Will my pricing change?

No. Nothing about your pricing changes when you move to the REST API.

I already have API credentials. Do I still need a new key?

Yes. Credentials listed under Legacy API Credentials only work with the legacy APIs, and will stop working at the switch-off. Create a new key under Basic Authentication.

Do I need to migrate everything at once?

No. Your legacy credentials keep working until the switch-off, so you can move one integration at a time. Start with the ones your business relies on most.

Can I use my legacy credentials and my REST API key at the same time?

Yes, until the switch-off. For important messages, we recommend running both while you test, so there's no gap in sending. Keep your legacy credentials until you've finished migrating, because you can't create new ones from 31 March 2027.

Will messages sent through my legacy API show up in the REST API?

Yes. Both APIs use the same account, so they can see each other's messages, delivery reports and replies. Because of this, don't have two systems checking for delivery reports or replies at the same time. Use webhooks, or check from one system only.

Will my existing webhooks keep working?

Yes. Webhooks under Settings → API Settings → Webhooks aren't affected. If you use SMS Broadcast webhooks, message IDs for messages you send through the REST API are UUIDs (text, not whole numbers), so check that your system can handle them. See the SMS Broadcast migration guide. To get delivery reports for messages sent through the REST API, add "delivery_report": true to each message.

What TLS version does the REST API need?

Your system needs to support TLS 1.2 at minimum. We recommend TLS 1.3. Older systems usually fail with a generic connection or handshake error. Talk to your developer or hosting provider about updating your system before you migrate.

I only use the web app. Do I need to do anything?

No. Sending and receiving messages in the web app isn't affected.

I no longer use the API. Do I need to do anything?

No. The legacy APIs will switch off and nothing else about your account changes. If you're unsure whether something is still connected, contact our Support team and they can check for you.

Can I get an extension?

No. With 12 months' notice, the legacy APIs will be switched off for all customers on 29 October 2027.

Will I be reminded?

Yes. We'll send reminder emails throughout the year to accounts still using a legacy API, with the final reminder one week before the switch-off.

Can I use an AI coding assistant to help migrate?

Yes. The REST API documentation has a version made for AI tools such as Claude, ChatGPT or Cursor (see AI Integration). Each migration guide includes a starting prompt you can use.

Getting help

• REST API documentation
• Developer guides
• For help with your migration, or to check whether your account is affected, contact our Support team.

We'll keep this page updated throughout the migration period.