Sinch is now a Marketplace Partner in the SpaceX Super Intelligence (SpaceXSI) Partner Network, which means teams building software in Grok Build (formerly Cursor) can have its AI agent add text messages, rich messages, phone calls, identity checks, and email to their apps, and test every one of them for real before launch.

You can start today. The Sinch plugin is in the Cursor Marketplace.

SpaceXSI set up the network in October 2026 for companies building around Grok, its AI platform for business. Transformation Partners help enterprises roll Grok out across their operations, while Marketplace Partners like Sinch publish plugins that connect Grok’s tools to the services companies already run on.

As one of the first Marketplace Partners, Sinch looks after communications, so whatever a team builds in Grok Build (formerly Cursor) can reach the people it’s meant for by text, call, or email.

Grok Build (formerly Cursor) is SpaceXSI’s AI coding tool: a developer explains a feature in everyday words, and an AI agent writes the code for it.

The agent is a capable general programmer, but customer communications come with fine print it can’t be expected to know, from the carrier rules for texting in a particular country to what a phone does with a message it can’t display, or how to confirm who a customer is before they pay.

That’s where the Sinch plugin comes in. Sinch Skills give the agent current instructions for each Sinch service before it starts writing, and a secure link to your Sinch account lets it send a test to a real phone and see what actually arrived.

Why does this matter?

AI coding tools have shortened the time it takes to write software, but reaching a customer has always depended on more than code. Sender names have to be verified, campaigns registered with carriers, and messages adapted to whatever phone is on the other end, and if one of those is missed, a reminder that worked on a developer’s laptop never shows up.

Sinch handles more than one trillion customer interactions a year in over 190 countries. The plugin puts that infrastructure where the building happens, so teams learn on day one whether a journey works for real customers.

What does this look like in practice?

To try it on something with real stakes, our developer advocate built a payment reminder journey for RockBank, a fictional lender whose customers ignore reminders sent by post. The goal was to reach them on channels they check every day.

Here’s what a RockBank customer gets:

1. A reminder they’ll see. Three days before a payment is due, a branded message from a verified RockBank sender lands in their phone’s regular messaging app, showing the amount and a “Pay now” button. Text and rich messages both go through Sinch’s Conversation API, so phones that can’t display rich messages automatically get the same reminder as plain text.
2. A security check before money moves. “Pay now” opens the payment page, which first asks for a one-time passcode sent to their phone by Sinch’s Verification API.
3. A receipt in their inbox. Once they’ve paid, an email sent through Mailgun, Sinch’s email platform, confirms the amount, date, and reference number.
4. A phone call if the payment slips. If it’s still outstanding two days later, RockBank follows up with an automated voice call placed through Sinch’s Voice API.

Normally each of those channels is a project of its own. He built and tested the whole journey in one afternoon, describing every step to the agent in plain language and checking the results on his own phone and inbox as they came in.

When the build takes an afternoon, the longest part of the project is usually waiting for approvals. Texting US numbers requires carrier registration (known as 10DLC), and rich messaging (RCS) is approved country by country, which can take days. The teams that launch fastest file both the same day they start building, and Sinch’s registration guide walks through the US process.

Code review and compliance sign-off stay with your teams, and the plugin gives them more to work with: readable code, and test results from real delivery.

For developers who want the technical detail, our developer advocate wrote up every prompt and gotcha from the build.

Developers can install the Sinch plugin from the Cursor Marketplace and connect it to a Sinch account. It works the same way in Grok Build (formerly Cursor). New to Sinch? Sign up free.

Leading a team that wants to build customer journeys this way? Talk to your account manager, or let’s chat.

Is Grok Build the same as Cursor? Yes. Grok Build is the new name for Cursor, SpaceX Super Intelligence’s (SpaceXSI) AI coding tool. The Sinch plugin works the same in both and installs from the same marketplace listing.

What does it mean that Sinch is a SpaceXSI Marketplace Partner? Sinch publishes a plugin that lets the AI agent in Grok Build (formerly Cursor) add Sinch messaging, voice, verification, and email to the apps it builds. Marketplace Partners are one of two tracks in the SpaceXSI Partner Network, which launched in October 2026.

What’s included in the Sinch plugin? Sinch Skills, which give the AI agent current instructions for each Sinch service, and a secure connection to your Sinch account so it can send test messages. Developers also get chat commands such as /send-message.

Do I need a Sinch account to use the plugin? Yes, to send real messages. The plugin connects to your own Sinch account, and you can sign up free at dashboard.sinch.com.

Does the Sinch plugin send real messages? Yes. It acts on your live Sinch account, so tests reach real phones. Use your own phone number while you build.

Is the Sinch plugin open source? Yes. The source is on GitHub at sinch/sinch-plugins.

Can the AI agent handle carrier registration for me? No. US text message registration (10DLC) and rich messaging (RCS) approval run on the carriers’ timelines. Start them the day you start building.

Author: Linda Le Phan Linda is a Senior Marketing Manager at Sinch.