Massed Compute vs Vast.ai

Massed Compute

The hosted MCP server and REST API accept OAuth grants or API tokens in read-only and full-access tiers, and all 17 tools carry typed schemas and safety annotations in a public server card. No status page, rate limit figures or API changelog were found, a launch has no idempotency key, and the governing terms could not be read.

Vast.ai

API keys can be limited by permission category and by resource ID, the REST API has a public OpenAPI 3.1 file, and the CLI ships weekly with a skill file for coding agents. Machines belong to independent hosts, prices move with the market, rate-limit thresholds are unpublished, and there is no SLA or free tier.

Massed Compute

1. Use https://vm.massedcompute.com/api/v1. The older docs at api-docs.massedcompute.com describe a separate marketplace API on api.massedcompute.com whose keys come from support.
2. Ask the owner for a read-only token unless the task must launch or terminate. Read-only credentials cannot call launch, restart, terminate or SSH key changes.
3. Call gpu_inventory_list and images_list before instances_launch. Product names and image IDs are free values, and SXM-only images do not run on PCIe cards.
4. Expect 402 on launch until the owner has added credit and set a recharge amount and threshold. List instances before retrying a launch.
5. Terminate to end billing. Stopping keeps the full hourly charge, and termination deletes the instance data.

Vast.ai

1. Create a scoped key with vastai create api-key --permissions for the agent. A default key has full account access, billing and key management included
2. Pass --raw on every CLI command for JSON output, and -y on vastai destroy instance, which otherwise waits for a confirmation prompt
3. Register an SSH key with vastai create ssh-key before creating an instance, or the host is unreachable
4. Destroy instances when finished. A stopped instance still bills storage, and a zero balance without a saved card leads to deletion
5. Back off on HTTP 429 yourself when calling REST directly. The CLI retries 429 three times from 0.15 seconds
6. Filter searches with verified=true or the Secure Cloud option for sensitive data, and set a dph_total price cap