Latvian composer  Santa Ratniece started her musical studies with piano playing classes at Valmiera Music School. In 1992 she took up music theory classes in Emils Dārziņš College of Music in Riga. She continued her musical education at J.Vītols Latvia  Music Academy and  graduated  in musicology (2000) and in composition (2002) with professor Romualds Kalsons. Later on she studied composition  with  English composer David Rowland at Enschede Conservatory in Netherlands. Afterwards Santa Ratniece went on with her studies at Estonian Academy of Music and Theatre with Estonian composer Helena Tulve and in 2007 she obtained her MA. 

Santa Ratniece`s music has been played in Europe, Australia, Canada, United States and South America by Latvian Radio Choir, Orchestra RIGA, Sinfonietta Riga,  Liepaja Symphony Orchestra, Latvian National Symphony Orchestra, vocal group Putni, pianists Vestard Shimkus and Reinis Zariņš, harpsichordist Ieva Saliete, Trio Art-i-Shock, Trio Palladio, ReDo string quartet (Latvia),  NYYD Ensemble, Ensemble Resonabilis, Estonian National Male choir, Estonian National Symphony orchestra  (Estonia), Ensemble Sarband, Ensemble Recherche, Leipziger Blaserquintett, Ensemble Avantgarde,  Ensemble RARO, Deutsch-Skandinavische Jugend-Philharmonie (Germany), Arditti Quartet, BBC Singers (England), Nederlands Kamerkoor, Cappella Amsterdam, Scordatura Ensemble (The Netherlands), Musiques Nouvelles, Ensemble Fractales (Belgium) Quatuor Molinari (Canada), Sydney Symphony Fellows (Australia), SOCO Ensemble (Uruguay), Kronos QuartetThe Crossing choir, International Contemporary Ensemble, Chelsea Music festival orchestra, iSing Silicone Valley choir (United States), ConTempo Quartet (Rumania), Ensemble Reconsil (Austria), Chamber Choir Ireland (Ireland), The Moravian Philharmonic Orchestra, Lichtzwang Ensemble (Czech Republic) Forbidden City Chamber orchestra (China), Ars Nova Copenhagen (Danemark) and others.

Santa Ratniece first came into public view in 2004 after winning the 1st prize at the 2004  UNESCO International Rostrum of Composers in Paris for her work sens nacre (in the category of composers under 30), performed by Ensemble Nove, conductor Normunds Šnē. 

Hirondelles du Coeur for mixed choir and orchestra - nominated for Grand Music Award 2006; 
Saline - Latvian Annual Award for culture 2006 of the newspaper "Diena";
Sens nacre for ensemble - Copyrights' Infinity Award 2007;
Saline - selected work 2008 UNESCO International Rostrum of Composers;
Shant Nadi - selected work 2012 UNESCO International Rostrum of Composers;

Chu Dal for choir - Copyrights’ Infinity Award 2011;

Concerto for piano and symphonic orchestra - Latvian Annual Award for Culture 2014 of the newspaper "Diena" (performed by pianist Vestard Simkus and Liepaja Symphony orchestra);

Concerto for piano and symphonic orchestra - nominated for Grand Music Award 2014 in Latvia;

Pļavas for wind orchestra - nominated for the Grand Music Award 2019;
Music for the movie "Natural Light" - Lielais Kristaps National film award 2021 (best composer).

Santa Raniece`s music has been widely played in Baltic states. Her compositions have been  included regularly in the programs of Arena Festival, Skaņu Mežs Festival, Latvian New Music Days, Introvert Music Festival, Autumn Chamber Music Festival, Cesis Art Festival (Latvia), Estonian Music Days 2007, 2008, 2023, Autumn Festival, AFEKT 2022 (Estonia), ISCM World Music Days Vilnius 2008, GAIDA 2009, Music of Changes 2011 (Lithuania).

Santa Ratniece has participated with her music in well-known festivals, such as Présences 2006, Tenso Days Paris 2007 (France),  Klangspuren 2006, Klangraum im Herbst 2012 (Austria), The Baltic Sea Festival (Sweden), MusiMars 2006, Soundstreams 2012 (Canada), Cello Bienneale Amsterdam 2016, Tenso Dagen Amsterdam 2009, Koorbiënnale Haarlem 2011, Operadagen Rotterdam 2012 (The Netherlands), 2010 ISCM World New Music days Sydney (Australia), La Biennale di Venezia 2010 (Italy), Usedomer Music Festival 2010 (Germany), SOCO Festival 2011 (Uruguay), Vale of Glamorgan festival of music 2011, Brighton festival (United Kingdom), Month of Moderns 2013 (USA)), Warsaw Autumn 2013 (Poland), Mostly Mozart's Festival 2016, Chelsea Music Festival 2019, ACDA 2023 Convention (USA), SoundPlasma Festival 2021 (Germany), MusicOlomouc Festival 2021 (Czech Republic) and others.

In 2017 Santa Ratniece has been a Artist-in-residence at KulturKontakt Austria (Vienna). She was three times a composer-in-residence in Visby International Centre for composers in Sweden (2013, 2015, 2017).

In summer  2013 Santa Ratniece had her first American tour. The Crossing Choir of Philadelphia had the performances of Santa Ratniece’s three choir compositions in three concerts in the festival The Month of Moderns. Saline, Chu Dal and horo horo horo hata were sounding in three different venues of Philadelphia. New piece My soul will sink within me written for The Crossing Choir in collaboration with International Contemporary Ensemble of New York was premiered in summer 2016 in Philadelphia and New York at Mostly Mozart's festival, Lincoln Center for the performing Arts. Later on the album Seven responses was nominated for the Grammy Music Award 2016. In 2019 piece Leider liegt kaum Schnee for two sopranos and string orchestra was premiered at Chelsea Music Festival, conducted by Ken-David Masur. Album Rising w/the Crossing (live) with a piece horo horo hate hata was nominated for the Grammy Music Award 2021. 

Most of Ratniece`s music is devoted to the chamber choir, she has received regular commissions from Latvian Radio choir and relationship with the choir started with  Saline in 2006 and  followed by Hirondelles du Coeur (2007, for choir and orchestra) horo horo hata hata (2008, for 12 voices), Chu Dal (2009), Fuoco Celeste (2011 for cello solo and choir) and Nada el layli (2015) for  kemenche, qanun and choir), Vigilia del Mattino (2017) for harp and choir, nakts gaisma (2021).
Latvian Radio Choir, with conductors Sigvards Kļava and Kaspars Putniņš, recorded two albums with Ratniece's music - Saline (2011) and Vigilia del Mattino (2021),published by "Skani". 

Latvian Radio choir chamber singers are the soloists in Santa Ratniece’s first stage work - multimedia opera by Hotel Pro Forma - WAR SUM UP. Music. Manga. Machines. This opera was premiered in Latvian National Opera in 2011, conducted by Kaspars Putniņš,  having had further performances at Royal Theatre  in Copenhagen, BAM Howard Gilman Opera House in Brooklyn New York, Brighton Festival 2012 , ULTIMA Oslo Contemporary Music Festival 2011, Café Budapest Contemporary Arts Festival 2012, Materia Prima Festival 2012 (Poland), Transart Festival 2013 (Italy) OzAsia Festival (Australia) and on other more than twenty theatre stages around Europe and Asia (Taiwan and China). 

In the last years Peteris Vasks Foundation in Latvia has commissioned two pieces to Santa Ratniece -  mirdzums for the German RARO trio (Alina Pogostkina - violin, Reto Bieri - clarinet and Diana Ketler - piano) and - es mīlu mazo, smalko lietu; lyrics of Latvian poet Imants Ziedonis. It was premiered in August, 2013 by soprano Liene Kinca, flutist Dita Krenberga, cellist Eriks Kirsfelds and pianist Peteris Plakidis.

Santa Ratniece’s recent projects include commission from legendary Kronos Quartet. The premiere of Silsila took place in Big Concert hall of Stanford University in October 2014. In Silsila (chain in Arabic) we are following the Brahmaputra river down streams from Tibet, through India and Bangladesh to the Bay of Bengal. It is the highest major river in the world, which starts as a tiny little spring in Angsi glacier in Himalayas. In the curse of the piece we are descending from 5210 m above the sea level.

In 2014 she was involved in the project called Clybird’s lullaby, an artistic collaboration between Swedish artist Knutte Wester and children from  Ziemeli orphanage. The project is based on hand-made sculptural instruments,  so-called "clay birds", a small ocarina instruments that are traditionally used both in Sweden and Latvia. Knutte Wester - the artist from Sweden worked together with  children from Ziemeli orphenage and made the ocarinas from the clay.  Some of these small instruments  sometimes  have strong and clear tones, but others are completely out of tune, as if their wings were broken. Santa Ratniece got involved in the project and has written music especially for these clay birds and their characteristic sound. The representations of the lives of the children together with music form the basis for the Claybirds Lullaby, which the vocal ensemble Putni performed on October, 2014 in the St.Saviors Church in Riga.

Commission from Latvian Radio choir and Sarband ensemble - Nada el Layli was premierred in Oslo Church music festival in March 2015. It was a joint project, called Canticum Canticorum, where the Latvian Radio choir joined together with musicians from the Middle East, and five composers where creating the musical painting that integrates the Middle East traditional music in the Western contemporary choir music and vice versa. In Santas Ratniece’s piece the choir  was specifically created to feel secure and comfortable, just as in the maqam (place, space) tradition. The small Greek kemenche violin reflects qanun melodies, and its delicate arabesques are echoed in the quietly expressive sounds of the kemenche.

In October 2017 the premiere of Morning Rain took place in Beijing Concert hall. It was commissioned by China Ministry of Culture and premiered by Forbidden City Chamber Orchestra.