onOffice vs. FlowFact vs. PROPSTACK: An Honest Software Comparison for Estate Agents

Three names come up almost every time German estate agencies talk about their office software: onOffice, FlowFact and PROPSTACK. All three manage listings, contacts and marketing, all three charge per user per month, and all three claim to be the best choice. This article does not hand you a pre-decided winner. It explains what each system is actually built for, and points at the thing many agencies overlook when choosing: the best agency software is worthless online if your website never makes that data visible.

The three systems at a glance

Pricing and module names change regularly at all three providers — always confirm current figures directly with the vendor before deciding, not from this article.

onOffice — the incumbent with the broadest portal reach

onOffice has been established the longest and is correspondingly the most feature-rich all-rounder of the three. Agencies with many special workflows, multiple locations, or a strong need for the broadest possible portal integration typically find the deepest configuration options here. The trade-off: setup takes longer, and agencies looking for a lean system for day-to-day listing management often end up configuring features they never use.

Good fit for: established agencies with several agents, complex internal processes, and a need for maximum portal reach.

FlowFact — the compliance-focused constant

FlowFact has positioned itself for years as a solid, compliance-focused solution with a clear emphasis on the full marketing process: listing creation, acquisition, market valuation and contract documentation in one place. Agencies looking for a proven system without constant experimentation, and that value clean, GDPR-compliant documentation, get a tool that covers exactly that reliably, without surprising them with frequent interface overhauls.

Good fit for: agencies that want a proven marketing process without major disruption and that prioritise compliant documentation.

PROPSTACK — the most modern system with the strongest AI features

PROPSTACK is the youngest of the three providers and positions itself accordingly, with the most modern interface and the most visible AI features, for example in virtual staging or automated listing preparation. Setup is noticeably faster than with the established systems, and the ImmoScout24 integration is considered especially tight. The trade-off for the modern interface: PROPSTACK's feature depth for very complex, multi-stage workflows is not yet as deep as onOffice's.

Good fit for: modern, growth-focused teams that value fast onboarding and an intuitive interface over maximum feature depth.

What gets overlooked when choosing software: your website

This is the point we end up raising in practically every discovery call with estate agencies, regardless of which of the three systems they run: the agency software manages your listings excellently. Whether those listings actually get found on Google through your own website has almost nothing to do with choosing onOffice, FlowFact or PROPSTACK — it comes down to how the listings are embedded on the website.

Most standard websites built around these systems embed the listing feed through an iframe or a standard widget. That is quick to set up, but technically invisible to Google: each listing gets no dedicated URL, no indexable content, no chance to rank for "[property type] [neighbourhood]". This applies structurally in the same way to onOffice, FlowFact and PROPSTACK websites whenever they rely on that kind of widget.

The fix is the same regardless of which system you run: bidirectional synchronisation via the OpenImmo interface, which all three providers support, combined with real, server-rendered listing pages on your own domain instead of an iframe. You keep managing everything in the software you already use; the website pulls the data automatically, with an optional feed to ImmoScout24 and Immowelt on top.

Making the decision: which system fits you?

Instead of a blanket recommendation, three questions that tend to settle it in practice:

How complex are your processes really? A small team, a manageable range of property types, clear workflows — the extra depth of onOffice is often unnecessary configuration overhead. Multiple locations, many edge cases, complex internal approval chains — that is where the depth pays off.

How much do you value a modern, fast-to-learn interface? Teams with high staff turnover or little time for training benefit noticeably from PROPSTACK's faster onboarding.

How much does your business depend on ImmoScout24? If ImmoScout24 is your main marketing channel, PROPSTACK's especially tight integration is a real argument, not just marketing copy.

In the end, none of the three systems is fundamentally wrong. They differ in depth, speed and focus, not in quality. The more expensive mistake usually does not happen at the software decision — it happens afterwards, when the website built around it fails to make the carefully maintained listing data visible. Test this yourself with a simple search: look up the title of one of your current listings on Google. If your own site does not show up, that is a website problem regardless of which CRM you run, not a software problem.