The article presents a versatile single-photon-based quantum computing platform, named Ascella, which is accessible via a cloud service. Ascella consists of a high-efficiency quantum-dot single-photon source, a universal linear optical network on a reconfigurable chip, and a machine-learned transpilation process to correct hardware errors. The platform supports gate-based and photonic computation frameworks, achieving state-of-the-art fidelities for one-, two-, and three-qubit gates. It also implements a variational quantum eigensolver for calculating the energy levels of the hydrogen molecule with chemical accuracy and a photon-native quantum neural network for supervised learning classification tasks. Additionally, Ascella demonstrates heralded three-photon entanglement generation, a key step towards measurement-based quantum computing. The platform's performance and stability are validated through various benchmarks and applications, showcasing its potential for noisy near-term quantum computing tasks and large-scale fault-tolerant quantum computing.The article presents a versatile single-photon-based quantum computing platform, named Ascella, which is accessible via a cloud service. Ascella consists of a high-efficiency quantum-dot single-photon source, a universal linear optical network on a reconfigurable chip, and a machine-learned transpilation process to correct hardware errors. The platform supports gate-based and photonic computation frameworks, achieving state-of-the-art fidelities for one-, two-, and three-qubit gates. It also implements a variational quantum eigensolver for calculating the energy levels of the hydrogen molecule with chemical accuracy and a photon-native quantum neural network for supervised learning classification tasks. Additionally, Ascella demonstrates heralded three-photon entanglement generation, a key step towards measurement-based quantum computing. The platform's performance and stability are validated through various benchmarks and applications, showcasing its potential for noisy near-term quantum computing tasks and large-scale fault-tolerant quantum computing.