Softwr

Real Estate · head to head

CoStar vs Zillow

CoStar logo

CoStar

Real Estate

Commercial real estate data subscription with strict per-seat licensing, sold on multi-year contracts and enforced through active anti-piracy litigation against password sharing

From
On request
Rated
-
Full reviewWebsite
Zillow logo

Zillow

Real Estate

Consumer property search site whose actual product, Premier Agent, is paid lead placement sold to agents and brokers, not the free listings buyers browse

From
On request
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: CoStar per-seat licensing with no published rate makes budgeting for headcount growth unpredictable, since adding users typically requires a new negotiation rather than a self-service upgrade.; Zillow leads are frequently sold to multiple agents at once, so an agent is often bidding against competitors for the same buyer rather than buying an exclusive introduction.
  • They diverge on capability: CoStar covers Property and ownership records, Zillow covers Consumer listing search.
  • Prices and features above were last checked on 1 September 2026.

Where they differ

Only the attributes on which CoStar and Zillow actually diverge.

Attributes where CoStar and Zillow differ
AttributeCoStarZillow
PlatformsWebWeb, iOS, Android

Identical on both: starting price (On request), pricing model (quote), free tier (No), user rating (Not yet rated), category (Real Estate).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in CoStar

  • Property and ownership records
  • Lease and sales comparables
  • Tenant and space data
  • Market analytics
  • STR hospitality data
  • CoStar Real Estate Manager

Only in Zillow

  • Consumer listing search
  • Premier Agent placement
  • Lead connections
  • Performance dashboards
  • Zillow Flex
  • Agent profile and reviews

What people use each for

The jobs each tool is most often brought in to do.

CoStar

  • A commercial brokerage needing lease and sales comparables to support underwriting and pitch materialsnot Zillow
  • An institutional investor or lender wanting standardised market analytics across submarkets for portfolio decisionsnot Zillow
  • A corporate real estate team needing lease administration through CoStar Real Estate Managernot Zillow
  • An appraiser needing sourced, defensible comparable transaction data for valuation reportsnot Zillow

Zillow

  • An agent in a competitive metro wanting listing-page visibility on homes they do not personally representnot CoStar
  • A team wanting predictable lead volume to feed a follow-up system, accepting shared, non-exclusive leadsnot CoStar
  • A brokerage evaluating Zillow Flex as a pay-on-closing alternative to upfront advertising spendnot CoStar
  • A buyer or renter using the free consumer search, who is not Zillow paying customer at all and should understand that agent placement on a listing does not mean that agent represents the sellernot CoStar

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

CoStar

  • Per-seat licensing with no published rate makes budgeting for headcount growth unpredictable, since adding users typically requires a new negotiation rather than a self-service upgrade.
  • CoStar actively pursues legal action against password sharing and unauthorised access, which is a genuine compliance and litigation risk for a firm that is loose about login discipline, intentionally or not.
  • A June 2026 antitrust lawsuit names CoStar alongside major brokerages over an alleged price-fixing scheme, a live legal matter that could affect the company standing or practices during a long-term contract.
  • Multi-year contract structures reduce a buyer flexibility to switch providers even if a cheaper or better data source emerges during the term.
  • The breadth of the platform (property, hospitality via STR, lease admin) means a firm often pays for modules it does not use just to access the specific data set it needs.

Zillow

  • Leads are frequently sold to multiple agents at once, so an agent is often bidding against competitors for the same buyer rather than buying an exclusive introduction.
  • Reported lead-to-close conversion of roughly 1 to 3 percent means most paid connections do not become closed transactions, and the advertising spend has no guaranteed return.
  • Cost per connection varies heavily by ZIP code and competition, so budgeting is unpredictable and can spike in desirable areas without warning.
  • The agent shown as a contact on a listing is frequently not the listing agent, which has drawn criticism for consumer confusion about who actually represents the seller.
  • Placement is rented, not owned; an agent who stops paying loses visibility instantly, unlike a website or CRM investment that continues to compound in value.

Pricing, plan by plan

CoStar

On request
  • CoStar$undefined/year
    • Per named user licensing, no published rate
    • Multi-year contracts standard
    • Terms explicitly prohibit password or login sharing

Zillow

On request
  • Premier Agent$undefined/month
    • Consumer search and listings are free; agents pay for lead placement
    • Average cost per connection roughly $139 (non-major metro) to $223+ (major metro)
    • Monthly spend commonly $200-600 small markets, $1,500-5,000+ major metros

Which should you pick?

Choose CoStar if

  • You need property and ownership records.
  • You also want lease and sales comparables.
CoStar review

Choose Zillow if

  • You need consumer listing search.
  • You work on Web, iOS, Android.
  • You also want premier agent placement.
Zillow review

Questions people ask

Is CoStar or Zillow better?
Neither clearly leads. CoStar starts at On request and Zillow at On request, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, CoStar or Zillow?
CoStar starts at On request and Zillow at On request.
Does CoStar or Zillow run on more platforms?
CoStar runs on Web. Zillow runs on Web, iOS, Android.
What is CoStar best used for?
CoStar is most often used for a commercial brokerage needing lease and sales comparables to support underwriting and pitch materials, an institutional investor or lender wanting standardised market analytics across submarkets for portfolio decisions, a corporate real estate team needing lease administration through costar real estate manager, an appraiser needing sourced, defensible comparable transaction data for valuation reports. Of those, a commercial brokerage needing lease and sales comparables to support underwriting and pitch materials and an institutional investor or lender wanting standardised market analytics across submarkets for portfolio decisions are not what Zillow is typically brought in for.
What can CoStar do that Zillow cannot?
CoStar covers Property and ownership records, Lease and sales comparables, Tenant and space data, Market analytics. Zillow covers Consumer listing search, Premier Agent placement, Lead connections, Performance dashboards.

Answered from the vendors’ own pages

CoStar: Can multiple people share one CoStar login to save cost?

No. Terms explicitly prohibit this, and CoStar has an active pattern of suing individuals and firms for unauthorised access under shared credentials.

Zillow: Do home buyers or sellers pay Zillow?

No. Consumer search, Zestimates and listing browsing are free. Zillow revenue comes from agents and brokers paying for Premier Agent placement and leads.

CoStar: Is CoStar pricing published anywhere?

No. It is quote-only, licensed per named user, on multi-year contracts.

Zillow: Does the agent shown on a Zillow listing represent the seller?

Not necessarily. Premier Agent placement can show a paying advertiser as the contact even when they are not the actual listing agent.

CoStar: Is there a current legal risk in signing with CoStar?

A June 2026 antitrust lawsuit names CoStar and several major brokerages over an alleged price-fixing conspiracy; buyers with long-term contracts should track that litigation.

Zillow: Is there a cheaper alternative to paid placement?

Zillow Flex offers a pay-on-closing model instead of upfront ad spend in select markets, trading a lower risk of wasted spend for a referral fee on closed deals.

Share

Related pages

More on CoStar

More on Zillow

Keep looking

Other head to heads