How to Migrate Existing Automations to Next Gen Zaps

A practical field guide from Automation Ace.

Short answer: migrate existing automations to Next Gen Zaps one workflow at a time. Pick Zaps that strain classic limits, write their current behavior as a spec, have an AI agent build the Next Gen version, test it against the classic one with the same inputs, run both in parallel without duplicate side effects, then cut over, turn off the old Zaps, and document the new version.

Short answer

1. Choose candidates where Next Gen Zaps solve a real problem.
2. Turn the current Zap into a written spec, including problems to fix.
3. Build with an agent; review the plan and diagram.
4. Test with the same inputs as the classic Zap.
5. Run in parallel safely, then cut over.
6. Retire old Zaps and document the new workflow.

Before you start

• Access: Next Gen Zaps were in early access by request on paid plans at the time of writing, enabled for the whole account.
• An inventory: know which Zaps exist, who owns them, and which are healthy; see auditing Zaps.
• An agent: the Zapier editor's agent or an MCP client; see how to build and deploy Next Gen Zaps.
• A reviewer who can follow the generated logic.

Step 1: Choose what to migrate

Do not migrate for its own sake. If a classic Zap is simple and stable, leave it; see classic vs Next Gen Zaps.

Step 2: Document current behavior as a spec

Read the Zap's steps and recent history, then write what it actually does, what is wrong with it, and what must stay the same:

Classic Zap(s) being replaced: "Orders -> CRM" + "Orders -> Inventory"
                                 (linked by webhook)
Trigger:     New paid order in the store
Current behavior (from Zap history and step config):
  1. Find or create customer in the CRM
  2. For each line item (Looping, capped at 500) reserve inventory
  3. Paths: VIP -> Slack alert; Standard -> nothing
  4. Each Path repeats: log to Sheets, email confirmation
Known problems: duplicate Path endings, failures stop the run,
  large wholesale orders exceed the loop cap
Desired behavior: same outcome, one workflow, per-item error log,
  shared logging and email after branches rejoin
Must match: CRM fields, inventory reservations, email content
Tests: VIP order, standard order, 600-line wholesale order,
  out-of-stock item, CRM lookup failure

Including “must match” outputs and specific tests makes the migration verifiable. See the automation requirements doc template.

Step 3: Build the Next Gen Zap

• Give the agent the spec and ask for a plan before it writes code.
• Pick the same app connections the classic Zap uses (or shared, owned connections).
• Ask it to explain the logic back to you and check the diagram for every branch and loop.
• Keep the draft unpublished until tests pass.

For complex logic patterns, see Next Gen Zaps for complex workflows.

Step 4: Test against the classic version

• Run the draft with the same sample inputs the classic Zap processed recently.
• Compare outputs field by field in the destination apps.
• Run the edge cases from your spec, including failures.
• Use test or sandbox records where actions have real side effects; see why automations work in testing but fail when on.

Step 5: Run in parallel

Running both versions builds confidence, but two live workflows can double-send emails or double-create records. Options:

• Run the new version in a “log only” mode that records what it would do.
• Point the new version at a test destination for a week.
• Split traffic by a safe rule (for example, one store or one region) if the process allows it.

The same principles apply to any platform migration; see migrating Zaps without downtime and preventing two automations from updating the same record.

Step 6: Cut over and retire

1. Pick a quiet time and turn off the classic Zap(s).
2. Publish and enable the Next Gen version.
3. Process anything that arrived during the switch, checking for duplicates.
4. Keep the classic Zaps off (not deleted) for a few weeks as a rollback path.

Step 7: Monitor and document

• Watch the first live runs closely and check the error log daily at first.
• Decide what Agentic Management may do on its own; start with diagnose-and-propose.
• Save the spec and a plain-language summary with the published version; see documentation and handoff and version control.
• Measure the result: fewer failures, less maintenance, faster runs.

Migration checklist

• Candidate chosen for a real limitation, not novelty.
• Current behavior documented as a spec with must-match outputs and tests.
• Same, owned app connections.
• Plan reviewed and logic explained back.
• Outputs compared against the classic Zap.
• Parallel run without duplicate side effects.
• Cutover plan with a rollback path.
• Monitoring, autonomy rules, and documentation in place.

For the role changes this brings, see how Next Gen Zaps change the Zapier builder role.

Frequently asked questions

How do I migrate a classic Zap to a Next Gen Zap?

Choose a Zap where Next Gen Zaps solve a real problem, document its current behavior as a spec with must-match outputs and tests, have an AI agent build the Next Gen version, test it with the same inputs, run both in parallel without duplicate side effects, then cut over and keep the classic Zap off as a rollback path.

Which Zaps should I migrate to Next Gen Zaps first?

Start with Zaps that hit the 500-item loop cap, chains of Zaps linked by webhooks for one process, Paths with duplicated endings, and Code steps handling nested data. Leave simple, stable Zaps as they are.

Which automations should not be migrated yet?

At the time of writing, workflows that rely on Sub-Zaps, your most sensitive workflows, those needing Enterprise features not yet supported such as audit logs, processes still being redesigned, and Zaps without an owner to review the new version.

How do I run a classic Zap and a Next Gen Zap in parallel safely?

Avoid two live workflows sending the same emails or creating the same records. Run the new version in a log-only mode, point it at a test destination, or split traffic by a safe rule until outputs match.

Should I delete the old Zap after migrating?

Turn it off rather than deleting it, and keep it for a few weeks as a rollback path while you monitor the new version.