Yes, it is. The story draws from real - world scenarios, especially in terms of the police procedures and the concept of isolating an area like the bridges in a big city to contain suspects. This gives the movie a sense of authenticity and makes it more engaging as it feels like it could have really happened. The way the characters interact within this true - story - inspired framework also adds to the overall intensity of the film.
21 Bridges is not based on a true story. It's a work of fiction created by the filmmakers for entertainment purposes. However, it might draw inspiration from various crime and thriller genres to create a compelling narrative.