Legacy cluster
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
An EU migration runs in three stages. Synthflow copies your workspace, you switch your traffic to EU, and Synthflow copies the calls made in between. Synthflow books a call with you for stage 2, so you need someone technical available for it.
Stage 1: Workspace copy
Before your migration call, Synthflow copies your workspace to the EU cluster. The copy includes your agents, phone numbers, cloned voices, configuration, and call history.
This is a one-time copy. The EU and legacy workspaces are not kept in sync after it. Anything you change on the legacy workspace after the copy does not reach EU, so make agent and configuration changes in the EU workspace from this point on.
Stage 2: Traffic switch
You move your traffic to the EU workspace, one agent at a time if you prefer. Until you switch an agent, it keeps taking calls on the legacy cluster.
On the migration call, you switch a few agents together with Synthflow and test that calls work. If your numbers come through Twilio, Synthflow runs the Twilio cutover on the call. You then switch the remaining agents on your own, using the EU migration checklist.
Stage 3: Call history catch-up
Once you confirm that all your traffic runs on EU, Synthflow copies over every call made on the legacy cluster since stage 1. Your EU call history is then complete.
EU migration checklist
Work through this list for each agent you switch. Synthflow handles stages 1 and 3, so everything here is on your side.
Before the migration call
- If you connect your own Twilio account, send Synthflow your EU Twilio auth token.
- If your network restricts traffic by IP, add the EU egress addresses to your allowlist. Synthflow uses them for custom actions, webhooks, and MCP server calls.
- Pick a few agents to switch during the call, and make sure the people who manage your SIP trunks, API integrations, and workflows can attend.
For each agent you switch
- SIP trunks: point your PBX or SIP trunk at the EU SIP signalling and media addresses, and allow those addresses in your firewall.
- API calls: change the base URL in every integration that calls the Platform API to
https://api.eu.synthflow.ai/v2/. - Workflows: open every workflow that places a call. In each Make Phone Call step, set the cluster to EU. Workflows are not updated automatically, so check each one by hand.
- Test call: place an inbound and an outbound call, and confirm both appear in the EU workspace’s call logs.
After all agents are switched
- Tell Synthflow that every agent runs on EU, so Synthflow can run stage 3.
- Once stage 3 is done, remove the legacy addresses from your allowlists.
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.
- 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 likehttps://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, phone numbers, cloned voices, and call history.
For EU migrations, the workspace is copied once, before your migration call. Changes you make on the legacy workspace after that copy do not move. Calls made on the legacy cluster after the copy do move, in stage 3.
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: no planned outage. You switch traffic one agent at a time, and each agent keeps taking calls on the legacy cluster until you switch it.
Does everything move, including agents, prompts, knowledge bases, cloned voices, and call history?
Yes. For EU migrations, agents and configuration are copied once, before your migration call, so make later changes in the EU workspace. Calls made on the legacy cluster after the copy are moved once you confirm your traffic has switched.
Do I have to switch all my agents at once?
No. You can switch one agent at a time. Tell Synthflow once the last agent is switched, so the remaining call history can be copied.
Do my workflows switch to EU automatically?
No. Open each workflow that places a call and set the cluster in its Make Phone Call step to EU.
Do my API keys change?
No. Your existing API keys keep working after the migration.