Ms. Kuiper became finalist and laureate of the Nicola Martinucci Competition (2019), the International Vocal Competition ‘s Hertogenbosch (2014), laureate of the Dutch Classical Talent Award 2017, 1st Prize winner at the 2013 Concours Kasteel Doorwerth, Klaas Dijkstra Award winner at the 2012 Peter de Grote Festival in Groningen, and the Audience Award winner at the 2011 Presentation Concert of the Stichting Nederlandse Vocalisten Presentatie. Esther's velvety sound and versatile musicality allow her to perform opera, oratorio and Lied repertoire from different periods and styles.​ Highlights from her engagements include Waltraute in Wagner's Walküre under Jaap van Zweden (Zaterdagmatinee November 2019), Pastorkyña/Barena in Janáčeks Jenufa (NTR Zaterdagmatinee 2021), Dritte Dame in Mozart’s Die Zauberflöte with the Orchestra of the 18th Century (2021), Mrs. Segstrom in Sondheim's A Little Night Music at De Nederlandse Reisopera (2019), Dritte Dame in Mozart's Die Zauberflöte at La Monnaie in Brussels (2018), Verdi’s Requiem with NedPhO (2018) and with the Verdi Concert Choir Japan (2019), La Contessa di Ceprano at Dutch National Opera in Verdi's Rigoletto (2017) and the role of Youngest Daughter in Trauernacht - a music theatre performance with music by J.S. Bach, with Katie Mitchell and Raphael Pichon (Aix-en-Provence Festival production, Philharmonie de Paris, 2015).