Sandra Balej is a visual effects supervisor. Balej began her career as a finishing artist, honing her skills in assembling and refining visual elements for final shots. This early work laid the foundation for her transition to compositing supervision, where she led teams at several visual effects houses, including Method Studios. Her expertise in compositing enabled her to move into roles as an on-set and production VFX supervisor, where she became responsible for integrating complex digital effects into live-action environments.

Her credits include major Hollywood blockbusters such as Mulan (2020), where she served as Compositing Supervisor, and Ant-Man and the Wasp (2018), where she acted as Digital Effects Supervisor. She also worked on Elysium (2013), The Maze Runner (2014), Doctor Strange (2016), and Thor: Ragnarok (2017), handling the assembly of intricate visual sequences. Her work in the Marvel Cinematic Universe continued with television series, including WandaVision (2021), Loki (2021–2023), and Ms. Marvel (2022), where she held various supervisory roles, including Additional VFX Supervisor.

The industry has recognised Balej’s contributions through multiple nominations, including two Primetime Emmy Award nods for Outstanding Special Visual Effects in a Season or a Movie. She received these nominations for her work on WandaVision and Loki, where she served as an Additional VFX Supervisor.