Apptainer vs SingularityCE
Apptainer
apptainer.org
SingularityCE
sylabs.ioSide by side
| Figure | Apptainer | SingularityCE |
|---|---|---|
| Price from | Free | Free |
| Free plan | Yes | Yes |
| Free trial | — | — |
| Open source | — | — |
| Windows | Yes | — |
| macOS | Yes | — |
| Linux | Yes | Yes |
| API | Yes | — |
| Self-hosted | Yes | Yes |
| Plans published | 1 | 1 |
| Spec score · Container Engines | 8.9 (#1) | 7.3 (#24) |
| Spec score · Container Runtime Software | 8.9 (#1) | 7.3 (#24) |
| Purpose | Apptainer creates and runs containers that package software for portability and reproducibility. | SingularityCE creates and runs portable, reproducible containers that package software into a single file. |
| Security model | By default, users retain the same identity inside the container and cannot gain additional host privileges. | By default, the user inside a container remains the same user as outside and cannot gain additional privilege on the host. |
Plans
In their own words
Apptainer
Apptainer is a free container platform for creating and running portable, reproducible workloads, with a focus on shared systems and high-performance computing. It packages containers as immutable, single-file Singularity Image Format (SIF) images designed for transport and sharing. By default, users retain the same privileges inside and outside containers. Images can be signed and verified with PGP keys, PEM keys or X.509 certificates, and encrypted containers can run without writing decrypted contents to disk. Apptainer imports containers from OCI registries and aims to support most Docker Hub containers without changes. It can expose host resources such as GPUs, high-speed networks and parallel filesystems, and supports NVIDIA CUDA, AMD ROCm, Intel Gaudi and OCI Container Device Interface accelerators. Running Apptainer requires Linux; Windows and macOS need a Linux virtual machine, with Windows also listed via WSL2. Root access is unnecessary when user namespaces are available. Full functionality requires kernel support for FUSE and unprivileged user namespaces. Community support includes Slack, Google Groups and GitHub, with commercial services through CIQ.
SingularityCE
SingularityCE has no write-up on Specifiction yet; its figures are above.