RadioDNS is a method for a hybrid radio receiver, meaning one receiving the broadcast radio signal and connected to the Internet, to find the Internet address of the interactive service corresponding to the radio station actually tuned.
It uses the existing Domain Name System (DNS) to allow the connected radio receiver to look up web resources based on their broadcast parameters, such as the station identifier received within the broadcast signal. Every initial DNS lookup requires inquiring the DNS server belonging to RadioDNS Ltd. Having a station listed on this DNS server costs $10 a year. At the moment (2018) the fee is waived.
The project is an open standard, initially created by a series of broadcasters and manufacturers.
RadioDNS was originally created as a collaborative project between Global Radio (at that time called GCap Media) and the BBC, to investigate creating a mechanism for linking Broadcast Radio and IP delivered webservices.
The concept was first presented to the WorldDMB Technical Committee in Munich in May 2008. Interest in the project grew, to the extent where it was necessary to formalise the project.
The First General Meeting of RadioDNS was hosted by the European Broadcasting Union in Geneva in October 2009 
The Second General Meeting of RadioDNS (held on 16 February 2010 in Geneva) adopted the Statutes, Intellectual Rights Policy, Trust Model and Membership Process, and thus effectively established RadioDNS as a not-for-profit organisation.
The standard supports several radio bearers including VHF/FM, DAB, DRM and AMSS. Using a standardised format, a fully qualified domain name (FQDN) is constructed and queried. This returns a CNAME record known as the "authoritative FQDN", which is a domain that represents the requested radio service. From this domain, SRV record lookups can be performed to verify the availability and location of various other applications that utilise RadioDNS.
Querying this domain returns a CNAME record:
09580.c479.ce1.fm.radiodns.org canonical name = rdns.musicradio.com.
This CNAME record can then be used to look up SRV records that advertise the availability of applications based upon RadioDNS (in this example an application identified by the name radiovis):
_radiovis._tcp.rdns.musicradio.com service = 0 100 80 vis.musicradio.com.
The linking of broadcast media with IP, as RadioDNS enables, allows additional functionality on receivers.
One example is RadioVIS, which is an open standard for accompanying visuals for radio broadcasts. The Sensia, manufactured by PURE, is an example of a receiver with this functionality built-in. Demonstrations have also been made of RadioVIS running on a mobile phone.
Other examples being worked on by the RadioDNS project include RadioEPG, a way of obtaining additional station and programme information; and RadioTAG, a way for a listener to request more information, or simply bookmark a place, in a live broadcast.
RadioText+ (RT+) in RDS (FM) and DynamicLabel Plus (DL+) in DAB already provide content type Programme.PROGRAMME.HOMEPAGE (and possibly Info.INFO.URL) which allows radio stations to pass along their website address to receivers without the need for an additional parallel -- and in the future potentially paid -- listing on the DNS server of RadioDNS Limited.
- "Register a Station with RadioDNS".
- About RadioDNS Archived 2010-03-03 at the Wayback Machine., radiodns.org
- EBU Technical Journal - RadioDNS Gets Formal In Geneva, tech.ebu.ch
- RadioDNS Statutes, radiodns.org
- RadioDNS Intellectual Property Rights Policy, radiodns.org
- RadioDNS Trust Model, radiodns.org
- RadioDNS Membership Application Process, radiodns.org
- RDNS01 Technical Specification, radiodns.org
- RadioDNS Project Website, radiodns.org
- BBC RAD labs blog: Experiments with RadioDNS, bbc.co.uk
- Pluxbox RadioManager, SaaS radio solution provider
- CasterPlay, RadioVIS Monitor for Windows
- MyRadioDNS.com, SaaS solution provider
- metadata.radio Saas radio metadata provider