Zillow API Network

GetRateSummary API

The GetRateSummary API returns the current rates per loan type — as well as rates from a week ago — from Zillow Mortgage Marketplace. Current supported loan types are 30-year fixed, 15-year fixed, and 5/1 ARM. Rates are computed from real quotes borrowers receive from lenders just seconds before the rate data is returned. The GetRateSummary API returns rates for a specific state if the optional state parameter is used.

The GetRateSummary API Web Service is located at: http://www.zillow.com/webservice/GetRateSummary.htm

Also, check out Zillow's prebuilt mortgage rate widgets.

The parameters of the API are:

zws-idThe Zillow Web Service Identifier. Each subscriber to Zillow Web Services is uniquely identified by an ID sequence and every request to Web services requires this ID. Click here to get yours. Yes
stateThe state for which to return average mortgage rates. Two-letter state abbreviations should be used (AK, AL, AR, AZ, CA, CO, CT, DE, FL, GA, HI, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NV, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WA, DC, WI, WV, WY). If omitted, national average mortgage rates are returned. No
outputThe type of output desired. Specify 'xml' for XML output and 'json' for JSON output. If omitted, 'xml' is assumed. No
callbackThe name of the JavaScript callback function used to process the returned JSON data. If specified, the returned JSON will be wrapped in a function call with the specified function name. This parameter is intended for use with dynamic script tags. The callback function is only used for JSON output. No

The API result set:

Today's RatesA list of three rates for the following loan types as well as the number of quotes used to calculate the rates. The rates are determined by the last 24 hours of data.
  • 30 year fixed rate loans
  • 15 year fixed rate loans
  • 5/1 adjustable rate loans
Last Week's RatesA list of three rates (for the same loan types listed for "Today's Rates") as well as the number of quotes used to calculate the rates. The rates are determined by the last week of data.
Limit-warningIf this field is set to "true," it means you are approaching your call limit. It appears under the "message" element in the API result set:
<text>Request successfully processed</text>
This output field will not be returned if it is false.

Messages and Codes

The following table summarizes possible return codes from the API:

Error codeDescriptionResolution
0Request successfully processed
1Service error-there was a server-side error while processing the requestCheck to see if your url is properly formed: delimiters, character cases, etc.
2The specified ZWSID parameter was invalid or not specified in the requestCheck if you have provided a ZWSID in your API call. If yes, check if the ZWSID is keyed in correctly. If it still doesn't work, contact Zillow to get help with fixing your ZWSID.
3Web services are currently unavailable The Zillow Web Service is currently not available. Please come back later and try again.
4The API call is currently unavailableThe Zillow Web Service is currently not available. Please come back later and try again.
500Rate data unavailableZillow Mortgage Marketplace rate data is currently unavailable. Please come back later and try again.
501Invalid state abbreviation specifiedThe state abbreviation specified for the "state" parameter isn't valid. Please make sure the abbreviation is a valid two-letter state abbreviation (or omitted).

Sample API Call

Below is a sample call to the API returning XML data:

Sample API Output (XML)

    <?xml version="1.0" encoding="utf-8"?>
    <RateSummary:rateSummary xsi:schemaLocation="http://www.zillow.com/static/xsd/RateSummary.xsd /vstatic/9a7665f1f221ad96757e028b5f570e08/static/xsd/RateSummary.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:RateSummary="http://www.zillow.com/static/xsd/RateSummary.xsd">
        <text>Request successfully processed</text>
                <rate loanType="thirtyYearFixed" count="1252">5.91</rate>
                <rate loanType="fifteenYearFixed" count="839">5.68</rate>
                <rate loanType="fiveOneARM" count="685">5.49</rate>
                <rate loanType="thirtyYearFixed" count="8933">6.02</rate>
                <rate loanType="fifteenYearFixed" count="5801">5.94</rate>
                <rate loanType="fiveOneARM" count="3148">5.71</rate>
    <!-- H:1  T:1076ms  S:630  R:Thu Sep 11 13:54:50 PDT 2008  B:3.0-comp_rel_b-SNAPSHOT -->

Below is a sample call to the API returning JSON data:

Sample API Output (JSON)

    cb( { 
    "request" : { 
        "output" : "json", 
        "callback" : "cb" 

    "message" : { 
        "text" : "Request successfully processed", 
        "code" : "0" 

    "response" : { 
        "today" : { 
            "thirtyYearFixed" : "5.91",
            "thirtyYearFixedCount" : "1252",             
            "fifteenYearFixed" : "5.68", 
            "fifteenYearFixedCount" : "839", 
            "fiveOneARM" : "5.49" 
            "fiveOneARMCount" : "685" 
        "lastWeek" : { 
            "thirtyYearFixed" : "6.02", 
            "thirtyYearFixedCount" : "8933", 
            "fifteenYearFixed" : "5.94", 
            "fifteenYearFixedCount" : "5801", 
            "fiveOneARM" : "5.71" 
            "fiveOneARMCount" : "3148" 
    } ); 

Have a question? Find help from a Pro here.