Alternatives
STACK plus five others (Descope, Aembit, Keycard, Composio, Stacklok) show up adjacent to the agent-runtime question. Each lives at a different layer of the stack and answers a different question. The right pick depends on which question is yours.
What's right for me? 30-second answer.
Pick the row that matches your situation. Read the head-to-head pages for the depth on each.
| Pick | If… |
|---|---|
| STACK | You ship agents that touch real services and want one signed chain across identity, credential proxy, runtime detectors, audit, and revocation. Cross-vendor neutral. EU AI Act Article 14 alignment is on your procurement checklist. |
| Descope | You already use Descope for customer authentication and want agent identity managed in the same console, with the same operational model. |
| Aembit | You need workload-to-workload credential brokering across multiple clouds (AWS, Azure, GCP, on-prem) and agents are one of many workloads in that mix. |
| Keycard | Your mental model leads with cryptographic attestation of the agent's runtime environment (SPIFFE, mTLS, Kubernetes service accounts before any token is issued). SOC 2 Type II, CMEK, and BYOC are procurement gates today. |
| Composio | Your dominant need is breadth of SaaS-tool integration (Gmail, Salesforce, Slack, hundreds of others) and the credential layer is a useful side feature rather than the wedge. |
| Stacklok | You have a Kubernetes platform team and want MCP servers deployed as pods with namespace-shaped boundaries, on Apache 2.0. |
What STACK does not compete on
Honest scope is a stronger procurement story than claiming full coverage. STACK is not the right tool for these.
| Use case | Who anchors it |
|---|---|
| Customer authentication at scale | Descope's home turf. |
| Workload identity for non-agent workloads across multiple clouds | Aembit covers more shapes. |
| Maximum SaaS-connector breadth | Composio has more named tool wrappers. |
| Kubernetes-native deployment as the operational model | Stacklok is structurally that. STACK runs managed SaaS. |
All vendor claims dated 2026-05-09 against current public materials. STACK is the comparing party. Claims about STACK are first-hand and verifiable in our docs. Claims about other vendors are sourced from their public marketing and documentation as of the date stamp. Page is updated quarterly and on material vendor announcements.