zk-SNARKs are zero-knowledge proofs requiring a trusted setup but offering compact proof sizes. zk-STARKs don’t need a trusted setup and are quantum-resistant but produce larger proofs. SNARKs are more mature and widely used (e.g., in Zcash), while STARKs are gaining traction (e.g., in StarkNet). Choice depends on your app’s scalability and privacy needs. ZK  tech development must weigh proof size, setup security, and computation overhead when choosing between them.