The best backend for an AI coding agent is the one that completes your required setup with the smallest safe permission set and the fewest human handoffs. Cohesivity, Supabase, and Firebase all expose agent-facing paths, but they start from different assumptions about accounts, existing projects, and underlying services.
Choose with one real provisioning test. Feature grids hide the login, authorization, and ownership steps where agent workflows usually stop.
The shortlist
Cohesivity for account-free project bootstrap
Cohesivity lets a coding agent create an ephemeral tenant with npx @cohesivity/init, then provision supported backend resources through one project context. The initial tenant needs no signup and expires after 72 hours unless a human chooses to claim it. Upstream provider credentials stay behind Cohesivity.
This fits greenfield builds where the agent needs some combination of Postgres, social login, object storage, hosting, realtime, email, Redis, vector storage, browser access, or model APIs. It is a poor fit when a team needs direct provider ownership from the first request, self-hosting, or a service Cohesivity does not expose.
The agent-operable backend guide explains the difference between calling a runtime API and administering the backend itself.
Supabase for a Postgres-centered platform
Supabase combines Postgres, Auth, Storage, Realtime, Edge Functions, and related developer tooling. Its official remote MCP server can manage projects, migrations, SQL, logs, functions, and branches. Supabase recommends project scoping, read-only mode where possible, feature-group restrictions, and keeping the MCP server away from production data. Those controls are documented in the Supabase MCP guide.
The setup includes browser authentication into a Supabase account or organization. That is reasonable for an existing team and less suitable when the goal is an unattended, account-free first build.
Firebase for Google-centered application services
Firebase provides Firestore, Authentication, Cloud Storage, Hosting, Functions, messaging, and other Google services. The official Firebase MCP server can create and manage Firebase projects, work with Authentication users and databases, inspect security rules, and expose Firebase tools to compatible coding agents. Its MCP documentation includes Claude Code, Cursor, and Windsurf among supported clients.
Firebase fits teams already using Google Cloud or applications built around Firebase's document and event model. It is less natural when the design assumes portable Postgres semantics.
Compare the complete setup path
| Question | Cohesivity | Supabase | Firebase |
|---|---|---|---|
| Can an agent create a project? | Yes, including an ephemeral no-signup path | Yes through account-scoped MCP tools | Yes through Firebase tooling and MCP |
| What human step remains? | Claiming, paid actions, and plan changes | Account authentication and organization access | Google authentication and project access |
| Primary data model | Managed Postgres plus separate services | Postgres-centered platform | Firestore, Data Connect, and Google services |
| Tool restriction | Cohesivity resource and tenant scope | Project, read-only, and feature-group options | Client permissions and selected Firebase tools |
| Hosting path | Managed Railway hosting through Cohesivity | Edge Functions plus external or adjacent web hosting choices | Firebase Hosting and App Hosting |
| Provider ownership | Cohesivity manages upstream providers | Team owns the Supabase project | Team owns the Google or Firebase project |
This table describes operating models, not a universal ranking. Verify current feature availability and limits in each platform's documentation before adopting it.
Five checks the demo should pass
Start from an empty repository
Do not pre-create the project for the test. Record every login, consent screen, copied key, and console setting. If those steps are acceptable for your workflow, count them as explicit dependencies instead of pretending they disappear.
Restrict the agent before connecting it
Limit the agent to one development project and only the tools the task needs. Supabase explicitly recommends project scoping and avoiding production. Apply the same rule to every platform, even when its documentation is less direct.
Retry one write
Interrupt project creation or schema setup, then repeat the request with the same operation identifier. The second attempt should return or reconcile the first operation rather than create another resource.
Inspect what reaches application code
The browser bundle should receive only public or short-lived credentials intended for it. Database administrator strings, management keys, and upstream provider keys belong in a server environment.
The walkthrough on how coding agents provision backend services shows the Cohesivity split between control-plane and application credentials.
Test ownership and removal
Find out how a human takes ownership, revokes the agent, exports data, and removes resources. Fast creation without a clean ownership path leaves the team with an application nobody can safely administer.
Pick based on the workflow already in front of you
Choose Cohesivity when an agent needs to begin a multi-service build before a human creates provider accounts. Choose Supabase when Postgres is the center of the application and the team is comfortable authenticating the agent into a Supabase organization. Choose Firebase when the product already belongs in the Google and Firebase model.
The prompt below compares those paths against this repository without creating anything.