The Real Estate Listing Markup Language (RELML) was developed by OpenMLS and John Petit of 4thWORLD Telecom.

<!--   Parameter Entities  -->   
 <!ENTITY % OTHER "OTHER">   
 <!ENTITY % NAME "NAME">   
 <!ENTITY % ACZ "ADDRESS?,CITY?,ZIP?">   
 <!ENTITY % PFW "PHONE?,FAX?,WEB?">  
 <!ENTITY % BA "BUILDING-AREA|ADD-INFO">  

 <!--   Notation Declarations   --> 
  <!--  Should point to media viewers at a universal site   --> 
 <!NOTATION gif SYSTEM "gview.exe">   
 <!NOTATION jpeg SYSTEM "jview.exe">   
 <!NOTATION mov SYSTEM "Movie Player">  

 <!ELEMENT RESIDENTIAL-LISTING (GENERAL,FEATURES,FINANCIAL,REMARKS,CONTACTS) > 
  <!ATTLIST RESIDENTIAL-LISTING   
 VERSION CDATA #FIXED "080698" >     
   

 <!-- *********************************************************************  -->   
 <!ELEMENT GENERAL 
 (IMAGE*,APN?,MLS?,TYPE,PRICE,AGE,LOCATION,STRUCTURE,DATES,LAND-AREA,STATUS,(%OTHER;)?,TERMS*) 
 >   
 <!--The IMAGE element does not include X and Y positions for the placement will more than-->   
 <!--likely be handled by XSL or CSS.-->   
 <!ELEMENT IMAGE EMPTY >   
 <!ATTLIST IMAGE    WIDTH    CDATA    #REQUIRED    
 HEIGHT    CDATA    #REQUIRED   
 SRC    CDATA    #REQUIRED  
 NAME CDATA #IMPLIED 
 DESCRIPTION CDATA #IMPLIED>  

<!ELEMENT APN (#PCDATA) >   
 <!ATTLIST APN    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >  

<!ELEMENT MLS (MLS-CODE,MLS-SOURCE?) >   

<!ELEMENT MLS-CODE (#PCDATA) >   
 <!ATTLIST MLS-CODE    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >  

 <!ELEMENT MLS-SOURCE (%NAME;,%PFW;) >   
 <!ATTLIST MLS-SOURCE    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >  

<!ELEMENT TYPE (#PCDATA) >  

 <!ELEMENT PRICE (#PCDATA) >  
<!ATTLIST PRICE      
 UNITS    (PESO|USDOLLAR|CANDOLLAR) "USDOLLAR" >     

 <!ELEMENT AGE (#PCDATA) >   
 <!ATTLIST AGE   
 UNITS    (YEARS|MONTHS) "YEARS">  

 <!ELEMENT LOCATION (%ACZ;,ROUGH?) >   
 <!ATTLIST LOCATION    
 COUNTRY    CDATA    #REQUIRED   
 STATE    CDATA    #REQUIRED    
 COUNTY    CDATA    #REQUIRED    
 SECURITY  (MLS-Only|Restricted|Public) "Public" >  

 <!ELEMENT ROUGH (#PCDATA) >  

 <!ELEMENT STRUCTURE ((NUM-BEDS|NUM-BATHS|SUPER-STRUCTURE|%BA;)*) >  

 <!ELEMENT NUM-BEDS (#PCDATA) >  

 <!ELEMENT NUM-BATHS (#PCDATA) >  

 <!-- If the property in question is a condo or such, SUPER-STRUCTURE is used -->   
 <!-- to describe the building containing that property -->   
<!ELEMENT SUPER-STRUCTURE ((NUM-UNITS|NUM-FLOORS|%BA;)*) >   

<!ELEMENT BUILDING-AREA (#PCDATA) >   
 <!ATTLIST BUILDING-AREA   
 UNITS    (SQ-METRES|SQ-FEET) "SQ-FEET" >  

 <!ELEMENT NUM-UNITS (#PCDATA) >  

 <!ELEMENT NUM-FLOORS (#PCDATA) >  

<!ELEMENT ADD-INFO (#PCDATA) >  

 <!ELEMENT DATES (LISTING-DATE,LAST-MODIFIED,EXPIRATION-DATE) >  

 <!ELEMENT LISTING-DATE (#PCDATA) >  

<!ELEMENT LAST-MODIFIED (#PCDATA) >  

<!ELEMENT EXPIRATION-DATE (#PCDATA) >  

<!ELEMENT LAND-AREA (#PCDATA) >   
 <!ATTLIST LAND-AREA   
 UNITS    (HECTARES|ACRES) "ACRES" >  

 <!ELEMENT STATUS (#PCDATA) >  

 <!ELEMENT TERMS (#PCDATA) >   
 <!ATTLIST TERMS    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >   
    
   

 <!-- *********************************************************************  -->   
 <!ELEMENT FEATURES (DISCLOSURES,UTILITIES,EXTRAS,CONSTRUCTION,ACCESS,(%OTHER;)?) >   
     
 <!ELEMENT DISCLOSURES (#PCDATA) >  

 <!ELEMENT UTILITIES (#PCDATA) >  

 <!ELEMENT EXTRAS (#PCDATA) >  

 <!ELEMENT CONSTRUCTION (#PCDATA) >  

 <!ELEMENT ACCESS (#PCDATA) >   
    
    
    
   

 <!-- *********************************************************************  -->   
 <!ELEMENT FINANCIAL 
 (ASSUMABLE,OWNER-CARRY,ASSESMENTS,DUES,TAXES,LENDER,EARNEST,DIRECTIONS,(%OTHER;)?) >  

 <!ELEMENT ASSUMABLE (#PCDATA) >   
 <!ATTLIST ASSUMABLE    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >  

 <!ELEMENT OWNER-CARRY (#PCDATA) >   
 <!ATTLIST OWNER-CARRY    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >  

 <!ELEMENT ASSESMENTS (#PCDATA) >   
 <!ATTLIST ASSESMENTS    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >  

 <!ELEMENT DUES (#PCDATA) >   
 <!ATTLIST DUES    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >  

 <!ELEMENT TAXES (#PCDATA) >   
 <!ATTLIST TAXES    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >  

 <!ELEMENT LENDER (#PCDATA) >   
 <!ATTLIST LENDER    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >  

 <!ELEMENT EARNEST (#PCDATA) >   
 <!ATTLIST EARNEST    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >  

 <!ELEMENT DIRECTIONS (#PCDATA) >   
 <!ATTLIST DIRECTIONS    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >   
    
    
   

 <!-- *********************************************************************  -->   
 <!--This is the freeform desciption section, the general impressions of the property-->   
 <!--The aspects of the property that make it special. The PROPERTY-REFERENCE attribute--> 
 <!--is for naming the property (by what title do you want people to refer to the property). -->   
 <!ELEMENT REMARKS (#PCDATA) >   
  <!ATTLIST REMARKS    
 PROPERTY-REFERENCE CDATA #IMPLIED>   
  
   

 <!-- *********************************************************************  -->   
 <!ELEMENT CONTACTS (COMPANY?,AGENT+,OWNER?,TENANT?,COMMISSION+) >  

 <!ELEMENT COMPANY (%NAME;,%ACZ;,%PFW;) >  

 <!ELEMENT AGENT (%NAME;,%ACZ;,%PFW;) >  

 <!ELEMENT OWNER (%NAME;,%ACZ;,%PFW;) >   
 <!ATTLIST OWNER    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >  

 <!ELEMENT TENANT (%NAME;,%ACZ;,%PFW;) >   
 <!ATTLIST TENANT    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >  

 <!ELEMENT COMMISSION (RECIPIENT,AMOUNT) >   
 <!ATTLIST COMMISSION    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >   
   
 <!ELEMENT RECIPIENT (#PCDATA) >   
 <!ATTLIST RECIPIENT    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >   

 <!ELEMENT AMOUNT (#PCDATA) >   
 <!ATTLIST AMOUNT    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >   

 <!ELEMENT OTHER (#PCDATA) >  
 <!ATTLIST OTHER    
 SECURITY  (MLS-Only|Restricted|Public) "MLS-Only" >   

 <!ELEMENT NAME (#PCDATA) >  

 <!ELEMENT ADDRESS (#PCDATA) > 
  <!ATTLIST ADDRESS    
 SECURITY  (MLS-Only|Restricted|Public) "Public" >  
  

 <!ELEMENT CITY (#PCDATA) > 
  <!ATTLIST CITY    
 SECURITY  (MLS-Only|Restricted|Public) "Public" >  
  

 <!ELEMENT ZIP (#PCDATA) > 
  <!ATTLIST ZIP    
 SECURITY  (MLS-Only|Restricted|Public) "Public" >  
  

 <!ELEMENT PHONE (#PCDATA) >  

 <!ELEMENT FAX (#PCDATA) >  

 <!ELEMENT WEB (E-MAIL,SITE) >   
   
 <!ELEMENT E-MAIL (#PCDATA) >  

 <!ELEMENT SITE (#PCDATA) >  
 

 <!ENTITY lt "<">   
 <!ENTITY gt ">">   
 <!ENTITY apos "'">   
 <!ENTITY amp "&">