Three thousand forms.
That's what the audit turned up when we started migrating an enterprise SaaS company off Marketo. Not three thousand thoughtfully-built forms, either. Roughly twenty of them were near-identical "request a demo" variants, cloned over the years by different regional teams. They'll become one HubSpot form. Multiply that decision by everything else in a decade-old Marketo instance and you have the real shape of an enterprise migration, which looks nothing like the "map your fields, flip the switch" checklists that dominate search results for this keyword. Here's what it actually involves.
Connect Salesforce before you touch field mapping
The single most useful sequencing trick in this project, and one I've never seen in a migration checklist: connect HubSpot to Salesforce first. The connector automatically creates the standard field set for you. Only then do you map what's left over, which turns out to be a short list of oddballs instead of hundreds of fields built by hand. Doing it in the other order means creating fields manually, then fighting the connector over duplicates. One decision, weeks saved.
The hard parts aren't contacts. They're the things Marketo did that HubSpot doesn't know about.
Contact and company records move fine. The work hides elsewhere. This instance had two Marketo custom objects to rebuild, one holding webinar engagement history, another holding roughly 150,000 subscription records from the billing system. It had three years of newsletter landing pages hosted on a legacy platform that will simply break at cutover, so we're testing raw HTML imports to preserve them. And it had a progressive-profiling feature that wasn't standard Marketo at all. A vendor built it years ago, nobody documented it, and someone now has to reverse-engineer what it does before we can decide whether HubSpot replicates it or replaces it. Every mature Marketo instance has at least one of these ghosts. Budget for the archaeology.
The contract end date is your project plan
This migration's timeline wasn't chosen. It was imposed, by the day the Marketo contract expires. Working backward from that date produced the plan: a testing buffer of two full weeks before cutover, and a freeze on new marketing builds in the weeks before the switch so the team isn't migrating a moving target. That freeze is the conversation nobody wants to have with a marketing team mid-quarter, and it's non-negotiable. A migration where campaigns keep launching in the old system until the final week is a migration that fails its testing window.
To be fair to the checklists: for a two-year-old Marketo instance with 40 forms and no custom objects, the simple version is roughly true, and you don't need an enterprise partner for it. The gap opens with scale and age. Ten years of marketing operations accumulate undocumented features, dead landing pages, and duplicated assets the same way a house accumulates cables nobody dares throw out.
If a Marketo migration is on your roadmap, start with the audit, not the timeline. Count your forms. You'll be surprised, and it's much better to be surprised now.
by Mark Fisher on August 23, 2026
CTO of Penguins Strategies. With over 20 years of business experience, Mark has modeled a perfect blend of marketing technology and strategy to take businesses to the next level. Mark is an expert in HubSpot implementation
