Operabase is an on-line database of opera performances, opera houses and companies, and performers themselves as well as their agents. Found at operabase.com, it was created in 1996 by English software engineer and opera lover Mike Gibb. Initially a hobby site, it became his full-time occupation after three years. Opera magazine describes the Operabase website as "the most comprehensive source of data on operatic activity".
The public site
By its tenth anniversary, the site received "about 10,000 visitors a day to the public site, who look at over four million pages a month between them. Of these, fewer than half use English, 17% use German, 12% Italian, 10% French, 9% Spanish." In autumn 2006, the British magazine Opera Now reported that "Operabase has taken on the Herculean task of making [the site] available to every European Union citizen in their own language - not only the 21 (as at January 2007) official languages of the EU, but Catalan, Icelandic and Norwegian as well." As of November 2012, the free public area of the site is available in 22 languages, and includes 37,000 performances, 40,000 artists, 700 opera companies, festivals and theatres, and the contact details and rosters of 400 artist managers. 
The Operabase professional section
Seven years after the public site was launched, a professional site followed and within three years, "200 opera houses from the Met to La Scala" were subscribers. The initial service offering for the 750 euro annual subscription fee was increased artist information and an opera casting tool. The casting tool was used for researching singers for a given role, but was particularly valued for finding replacement singers when there were emergency cancellations. The tool could not only put forward the names of all of the singers who had sung that role, but the artist schedules could be used to find if they were available, and the artists management and contact information could be used to make contact.
The professional services now also include a global database of opera productions available to rent or buy.
The database is now operated by Gibb and Muriel Denzler, who provide services to opera professionals for a fee, although the site is searchable by any web user at no charge.
As has been noted by Gibb and Denzler in an article on the website of Opera Europa (the European opera service organization similar to those which exist in the US and Canada, OPERA America and Opera.ca) they provide specialized services to opera professionals, with the site including "casting tools, artist records, management details, productions information". But they emphasize that "the site was originally created for the general public, who still provide 96% of its users".
In autumn 2010, Operabase produced a set of statistics for the opera world to mark the 250,000th performance on file. These statistics were presented at the third European Opera Forum, organised by Opera Europa in London in March 2011. In autumn 2013, the statistics were updated to show the 2012/13 season figures.
The Operabase rankings of the most performed operas formed the basis of a set of music questions in an edition of the BBC's University Challenge, broadcast in July 2014. Competitors were asked to identify three operas in the Operabase list from sound clips of Maria Callas.
Most played composers
In the five seasons 2008/09 to 2012/13, 2415 different works from 1161 different composers were played. The most popular composers were:
- Giuseppe Verdi, with 2,586 performances of 28 operas
- Giacomo Puccini, with 1,893 performances of 12 operas
- Wolfgang Amadeus Mozart
- Richard Wagner
- Gioachino Rossini
More than 600 of the composers played in this period were alive. The most frequently programmed of these were Philip Glass, Hans Werner Henze, and John Adams. Kaija Saariaho was the most played female composer, living or dead.
Most popular operas
In the 2008/09 to 2012/13 five-season period, a total of 2,415 different works were given, including over 300 world premieres. The most popular operas overall were:
- La traviata (1853, Verdi) with 553 performance runs
- Carmen (1875, Bizet) with 477 performances
- La bohème (1896, Puccini) with 471 performances
- Die Zauberflöte (1791, Mozart) with 464 performances
- Tosca (1900, Puccini) with 418 performances
The most popular operas from composers from the 20th century were The Turn of the Screw by Benjamin Britten and Lady Macbeth of the Mtsensk District (1934, Dmitri Shostakovich). The most popular works by composers alive on 31 July 2012 were the monodrama The Diary of Anne Frank (composed 1968, Grigory Frid), and the opera Dead Man Walking (2000, Jake Heggie).
Most operatic places
In the 2012/13 season, the cities with the most opera performances were:
- Vienna with 578 performances
- Berlin with 569 performances
- Paris with 437 performances
- Moscow with 424 performances
- St. Petersburg with 377 performances
- Edward Schneider (29 July 2001), "Singing and Their Suppers", The New York Times. Retrieved 13 May 2011.
- Charlotte Higgins, , "Operabase.com", The Guardian (London). Retrieved 20 November 2013
- Shapiro, Yehuda (June 2012), "Rarity Value", Opera magazine 63 (6): p.671
- Mike Gibb and Muriel Denzler, "Operabase's 10th Anniversary" on opera-europa.org
- Kenneth Richardson, "Net Results: Operabase, the internet tool for opera lovers and professionals, is ten years old. Kenneth Richardson talks to computer wiz and opera lover Mike Gibb about the journey so far and his ambitious plans to develop the site in future", Opera Now (London), Sept/Oct 2006.
- Operabase.com website Retrieved 13 November 2012
- Adam Sweeting, "The show must go on - but how?: When the star of the Royal Opera House's 'Ring' cycle fell ill the day before the show, everything seemed lost. Adam Sweeting tells the story of a frantic 24 hours.", Daily Telegraph (London), 25 Oct 2007. Retrieved 18 November 2012.
- Anaclase, Gilles Charlassier. Forum Opera Europa. Troisième forum des professionnels de l’art lyrique. Retrieved 13 May 2011.
- Opera Europa. OEuvres newsletter no.33 Spring 2011. Retrieved 19 November 2012.
- "Opera Statistics 2012/13" on operabase.com. Retrieved 24 June 2013
- "University Challenge 2014/15, Episode 3 on BBC iPlayer". BBC. Retrieved 4 August 2014.