Gumloop vs Prismatic

Gumloop

Gumloop's REST API has a public OpenAPI file with 105 operations, Markdown docs and a changelog with 28 dated releases since 9 July 2026. API keys need the $37 Pro plan, the trial needs a card, the key can travel in the URL, and self-serve content may be used to train Gumloop's models.

Prismatic

The GraphQL API covers 120 queries and 124 mutations with typed inputs, cursor pagination and Markdown documentation, and tokens follow seven user roles. No price is published, paid use runs under an agreement that is not public, and no API rate limit or idempotency key was found in the reviewed documentation.

Gumloop

1. Send the key as Authorization: Bearer and, for a personal key, add the x-auth-key header with the user ID. Do not put api_key in the URL
2. Create sessions with POST /agents/{agent_id}/sessions, then poll GET /sessions/{session_id}. A 202 means processing or queued, and the reply is not in the response
3. Supply your own session_id when creating a session. A repeat returns 409, which makes a retry safe
4. For streamed output send the same body with stream: true to ws.gumloop.com. api.gumloop.com answers 400 to it
5. Treat a webhook trigger URL as a password. It returns {"success": true} at once and never carries the agent's output

Prismatic

1. Have a person run prism login once, then store the output of prism me:token --type refresh as PRISM_REFRESH_TOKEN. Access tokens last 7 days
2. Read the errors array on every mutation. A failed mutation still returns HTTP 200
3. Pass sortBy with CREATED_AT when paging. Without a sort order pages can repeat or skip records
4. Use the regional host for the tenant, such as app.eu-west-1.prismatic.io and mcp.eu-west-1.prismatic.io
5. Create a guest user for a read-only agent, because tokens have no scopes of their own