Which Portal Actually Lists Rentals First?
You set up alerts on Rightmove. You set up alerts on OnTheMarket. A property appears on one before the other, and by the time you see it on the second portal, the landlord already has a stack of applications. If you picked the wrong portal to check first, you lost before you started.
So which one is faster?
We track rental listings across six UK property portals continuously. Using data from 25,987 Rightmove listings and 4,113 OnTheMarket listings across 120+ cities, here is what the numbers actually show.
Rightmove Has 6x More Rental Listings
Before talking speed, volume matters. A portal that lists properties first is only useful if it has properties to list.
Across our tracked cities, Rightmove carries 25,987 active rental listings compared to OnTheMarket's 4,113. That is a 6.3x gap.
The difference is even starker at the city level. Rightmove's busiest rental markets are Bournemouth (964 listings), Brighton (928), and Leeds (913). OnTheMarket's top city, Exeter, has just 63. Bristol, London, and Manchester all sit in Rightmove's top 10 with 700-900 listings each, while OnTheMarket's numbers across these cities are a fraction of that.
This is the baseline reality: Rightmove has the inventory. Over 90% of UK letting agents list there, and 78% of tenants start their search on Rightmove. If you use only one portal, it should be Rightmove.
But volume and speed are different questions.
Where OnTheMarket Gets Listings First
OnTheMarket offers agents something Rightmove does not: a feature called "New & Exclusive" (branded as "Only With Us"). Agents who opt in can list a property on OnTheMarket for 24, 48, or 72 hours before it appears on any other portal, including Rightmove.
These listings sit at the top of OnTheMarket's search results, displayed with three images instead of one. OnTheMarket's own data shows they generate roughly twice as many enquiries in the first 24 hours compared to standard new listings.
This is not theoretical. Thousands of properties each month go through this exclusive window. For renters in competitive cities, seeing a listing a full day before everyone else on Rightmove is a genuine advantage.
The feature dates back to OnTheMarket's founding. When it launched in 2015, agents had to agree to list on OnTheMarket plus only one other portal. That rule was scrapped in 2018, but the exclusivity window survived and remains active.
What Our Cross-Portal Data Shows
We matched 22 rental properties that appeared on both Rightmove and OnTheMarket within the same two-week period, using address matching across cities including Derby, Stafford, Ramsgate, and Birmingham.
The results:
- Rightmove listed first in 16 of 22 cases (73%)
- OnTheMarket listed first in 5 cases (23%)
- Same time in 1 case
When Rightmove listed first, the gap was often significant, averaging around 43 hours. When OnTheMarket listed first, the gaps were smaller, typically under 16 hours, consistent with agents using the "New & Exclusive" window then publishing to Rightmove shortly after.
One example: a property on Sherlock Street in Birmingham appeared on OnTheMarket 15.5 hours before Rightmove. Several Derby listings showed OnTheMarket first by minutes to hours. In Ramsgate, Rightmove led across all four matched properties.
The takeaway is not that one portal is universally faster. It depends on the agent. Agents using OnTheMarket's exclusive window will list there first. Everyone else defaults to Rightmove, which is the larger platform and where most agents upload first.
How the CoStar Acquisition Changes Things
In December 2023, US property data giant CoStar Group bought OnTheMarket for £99 million and committed £46.5 million in marketing spend in the first full year. That investment has paid off: OnTheMarket reports a 212% increase in traffic, a 47% rise in listing stock, and a doubling of property alerts compared to pre-acquisition numbers.
In March 2026, OnTheMarket signed a deal with the Connells Group, the UK's largest estate agency network, adding listings from roughly 1,200 branches. That alone brought close to 100,000 additional properties onto the platform.
Meanwhile, Rightmove faces a £1.5 billion class action from over 250 estate agencies alleging excessive fees. Agent frustration with Rightmove's pricing is growing: monthly fees rose 6.5% in 2024 while house prices rose just 1.3%.
The portal landscape is shifting. OnTheMarket's listing volume is growing, and if more agents switch or reduce their Rightmove spend, the speed and coverage dynamics will change with them.
OnTheMarket vs Rightmove: Head-to-Head Comparison
| Factor | Rightmove | OnTheMarket |
|--------|-----------|-------------|
| Active rental listings | 25,987 (across 120+ cities) | 4,113 (across 120+ cities) |
| Annual visits | 2 billion+ | Growing fast (up 212% post-CoStar) |
| Exclusive listing window | None | 24-72 hours ("Only With Us") |
| Agent coverage | 90%+ of UK agents, 16,000+ branches | Growing; Connells deal added 1,200 branches |
| Email alert speed | Batched, 2-8 hour delays | Similar batched delays for standard alerts |
| Lists first (our data) | 73% of matched listings | 23% of matched listings |
| Best for | Broadest coverage, most listings | Early access to exclusive listings |
How to Monitor Both Portals Without the Overhead
Checking two portals means two sets of saved searches, two alert schedules, and duplicate listings cluttering your inbox. Most renters either give up and stick to Rightmove, or check OnTheMarket occasionally and miss the time-sensitive exclusive listings that are the whole point.
Dwellio monitors Rightmove, OnTheMarket, OpenRent, Zoopla, SpareRoom, and PrimeLocation in one place. Set your search criteria once, and you get a single deduplicated alert within minutes of a matching property appearing on any portal. That includes OnTheMarket's exclusive listings during their early window. No duplicate management, no switching between apps.
We covered all six portals and their differences in our comparison of Rightmove, Zoopla, and OnTheMarket.
The Bottom Line
Rightmove lists more properties and lists most of them first. OnTheMarket lists some properties first, thanks to its exclusive window, and those are often the ones where being early matters most.
If you rely on one portal, you are either missing volume or missing speed. The renters who move fastest are the ones watching both simultaneously. Dwellio offers a 14-day free trial with no card required to do exactly that.