"Which portal has the best alerts?" is the wrong question, because the portals aren't really competing on alert quality — they're competing on which listings they have. The value of an alert is only as good as the stock behind it, and no single portal has all of it. Here's how each one's alerts work, and where they fall short.
How each portal's alerts work
Rightmove
Rightmove is generally the largest UK property portal by listing volume, and for London rentals that usually means the widest pool of agent-listed flats. You can save a search with your area, price and bedroom criteria and receive email alerts when new matches appear, with options for how often you're notified. If you only had time for one, this would be the default — but "one" is the mistake this article is about.
Zoopla
Zoopla works much the same way — saved searches with email alerts — and overlaps heavily with Rightmove, because many agents list on both. But the overlap isn't total: some agents favour one platform, some list at slightly different times, and Zoopla surfaces listings you won't necessarily see on Rightmove. Running Zoopla alongside Rightmove mainly buys you coverage of that non-overlapping slice.
OpenRent
OpenRent is the important different one. It's weighted towards landlord-direct lettings — properties listed by landlords rather than high-street agents — so a meaningful share of its stock never appears on the agent-heavy portals, or appears there later. You can set up alerts here too. If you skip OpenRent, you're not just getting fewer of the same flats; you're missing a category of flats entirely, often including better-value ones with no agent fee attached.
OnTheMarket
OnTheMarket is the fourth portal worth a saved search. Its coverage overlaps with Rightmove and Zoopla, and some agents post there (occasionally earlier than elsewhere) under its agent-first positioning. It's a smaller pool than Rightmove but still carries listings the others may not, which is the whole reason to include it.
The three gaps every portal alert shares
Whichever portals you pick, their alerts have the same structural limitations — and this is the real story:
- Delay. Alert emails are often sent on a schedule or in batches rather than the instant a listing goes live, so even a "new listing" alert can reach you after the fastest movers have already enquired.
- Duplication. The same flat gets listed by multiple agents and across multiple portals, so running several alert streams means the same property lands in your inbox several times, with no way for the portals to know they're all pointing at one flat.
- Siloing. Each portal only knows about its own listings. There's no cross-portal view, so you're left mentally merging four separate inboxes to work out what's genuinely new across the whole market.
Why running all of them is the point — and the catch
Because coverage is the differentiator, the correct strategy is uncontroversial: set the same saved search on Rightmove, Zoopla, OnTheMarket and OpenRent, and turn on the most immediate alert frequency each offers. That maximises the chance of seeing a given flat early on whichever portal it lands first.
The catch is that you've now created four overlapping alert streams with delay, duplication and no shared view — which is a lot of inbox to triage exactly when you need to move fast. That's the trade-off at the heart of London flat-hunting: full coverage and low noise pull against each other.
The aggregation case
Resolving that trade-off is precisely what an aggregator is for, and it's why we built FlatSignal (our product). Rather than replacing the portals, it reads the saved-search alert emails you already receive from them, folds duplicate listings of the same flat into one entry, scores each listing and groups them by London area — so the four inboxes become one ranked feed of what's actually new, each item still linking straight back to its original portal. It doesn't fix the portals' delay on their end, but it removes the duplication and the siloing, which is most of the daily pain. It's free to browse, and it's our honest answer to "which alerts should I use": all of them, in one place.
For the step-by-step on setting the underlying portal alerts up well, see how to set up property alerts that actually work.