Legacy cluster | Synthflow

Synthflow is retiring the legacy Global cluster. By the end of 2026, every enterprise workspace still running on it moves to a dedicated regional cluster: US or EU.

This page applies to all enterprise customers currently on the legacy cluster. It covers how your region is chosen, what Synthflow moves for you, and what your team needs to do. Nothing moves without notice.

Choosing your region

Through October, Synthflow emails every enterprise account on the legacy cluster to confirm which region you want to be migrated to.

Synthflow has made an initial assumption for each account based on your environment, and would rather check than guess. If you do not reply, your workspace moves to the US cluster.

Changing region after your migration is a manual migration handled by the professional services team. It is chargeable, and not everything carries across cleanly. If you need the EU, tell Synthflow now rather than after the move.

Moving to the US cluster

Synthflow migrates your agents, call logs, and actions for you, and your API base URL keeps working.

The US cluster sends and receives traffic from different IP addresses than the legacy cluster. If your network restricts traffic by IP, add the US addresses to your allowlist before your migration date:

Action IPs: US egress IP addresses are used for custom actions, webhooks, MCP servers, and other outbound requests from Synthflow to your systems.
Telephony IPs: US SIP signalling and media addresses are used if you connect your own PBX or SIP trunk to Synthflow.

Keep the legacy addresses in place until your migration is complete, then remove them.

Moving to the EU cluster

There is some work at your end:

Repoint your API base URL to the EU endpoint. Synthflow agrees a specific date and time with you to do it so that no data is lost in the switchover.
If you connect your own Twilio account, send Synthflow your EU Twilio auth token.

Synthflow coordinates the whole thing with you directly and gives you plenty of notice, but it is worth knowing now that you need someone technical available on the day.

Send your EU Twilio auth token

Twilio issues separate credentials for each region. The auth token you connected on the legacy cluster belongs to Twilio’s US region, so the EU cluster needs your Ireland (IE1) auth token. Without it, your Twilio integration does not connect after the move. Send it by Friday 9 October 2026.

You share the token through Password Pusher, an EU-hosted tool that creates an encrypted link which deletes itself after it is opened. This keeps the token out of email threads.

Copy your IE1 auth token from your Twilio Console. You can find more details in the Twilio guide. If you have more than one workspace, copy the token for each.
Open eu.pwpush.com/p/new. This link opens the form directly. No account is needed.
Enter your workspace ID and token in the Secret Text field, in this format. Repeat the two lines for each workspace.
```
Workspace ID: {your workspace ID}
EU Twilio Token: {your IE1 auth token}
```
Set the expiration to 7 days and 1 view.
Protect the link from email scanners. Under Additional Options, click Show / Hide and tick Use a 1-click retrieval step. Some email security tools open links automatically to scan them. Without this setting, that scan counts as the link’s one view and the link expires before Synthflow can open it.
Click Push It! and copy the link it gives you. It looks like https://eu.pwpush.com/p/6nspm9ynrftpmds_sw/r.
Reply to the migration email with the link.

Synthflow replies to confirm the token was received.

Never paste the auth token itself into the email. If the link shows as already viewed before Synthflow confirms receipt, rotate your IE1 auth token in Twilio and send a new link.

What moves with you

Everything inside your workspace moves, including agents, prompts, knowledge bases, and call history. For EU migrations, Synthflow runs a final sync immediately before you switch over, so anything you create or change in the run-up comes with you.

Your API keys do not change.

FAQ

Do I have to do anything if I'm moving to the US cluster?

Your base URL keeps working. If your network uses an IP allowlist, add the US egress IP addresses for actions and webhooks and the US SIP signalling and media addresses for telephony before your migration date.

Do I need to send a Twilio auth token?

Only if you are moving to the EU cluster and connect your own Twilio account. If you use Synthflow-provided numbers or are moving to the US cluster, there is nothing to send.

Can I have both US and EU?

Not within one workspace. A second region requires a second workspace, provisioned and billed separately.

What happens if I don't reply to the region email?

Your workspace moves to the US cluster. Moving region afterwards is a manual migration handled by the professional services team. It is chargeable and not everything carries across cleanly, so it is worth telling Synthflow now if you need the EU.

Will there be downtime?

US customers: no. EU customers: a short coordinated window during the agreed switchover slot, which Synthflow sizes with you when the migration is scheduled.

Does everything move, including agents, prompts, knowledge bases, and call history?

Yes. For EU migrations, Synthflow runs a final sync immediately before you switch over, so anything you create or change in the run-up comes with you.

Do my API keys change?

No. Your existing API keys keep working after the migration.