Announcing Qiskit SDK v2.3

Building on the momentum established across the v2.x series, which has centered on positioning Qiskit as the leading platform for hybrid quantum-HPC workflows, Qiskit SDK v2.3 delivers a significant expansion of the C API, alongside faster, more flexible tools for building and optimizing quantum circuits.

Major updates include:

• Custom transpiler passes in C - Write custom transpiler passes through Qiskit's C API using the new QkDag object and an expanded QkTarget object, which enable step-by-step inspection, modification, and extension of the compilation process - without rebuilding the entire compiler pipeline.

• Faster hardware layout selection - Upgrades and Rust-driven performance enhancements to VF2Layout and VF2PostLayout improve the speed and scalability of circuit-to-hardware layout selection, reducing compilation overhead and improving fidelity on quantum hardware.

• New multi-qubit Pauli measurement The new PauliProductMeasurement instruction enables joint projective measurement across multiple qubits in a single operation, unlocking compilation to Pauli-based computation - a common representation in fault-tolerant quantum computing.

• Improvements in early fault-tolerant transpilation - Performance and feature enhancements for transpilation to early fault-tolerant targets - especially Clifford+T targets - help users more efficiently build transpilation pipelines for future QPUs.

These capabilities give developers greater flexibility to customize quantum circuit optimizations and integrate with existing HPC workflows. Visit the blog for the full technical summary, and see the changelog and the v2.3 release notes for more information.