Convex vs Supabase for AI agent apps (realtime, auth, DB)

The short version

Convex feels like "build fast with guardrails" while Supabase feels like "build anything with Postgres." If you want a tightly integrated, realtime-first backend where functions and data live together, Convex is clean and fast. If you want the flexibility and ecosystem of Postgres with strong auth and an open SQL surface, Supabase wins.

For AI agent apps, the right pick depends on whether you prioritize realtime orchestration or database control.

What an agent app needs from a backend

AI agents create a backend workload that's slightly different from typical CRUD apps:

• Realtime coordination: agents need to react to new events quickly.
• Structured memory: you'll store prompts, traces, and run logs.
• Auth and tenancy: agents often act on behalf of users; you need clean boundaries.
• Safe mutation workflows: guardrails to avoid corrupting state.

Both Convex and Supabase can do this, but they push you toward different architectures.

Convex: integrated functions + data

Convex positions itself as a realtime backend where functions and data live in the same environment. You write backend logic as functions, and the data model is built for reactive queries.

Where Convex shines

• Realtime by design: queries auto-update; great for agent dashboards.
• Functions tied to data: logic and data are bundled, reducing glue code.
• Consistency model: strong guardrails for state changes and transactions.
• Developer velocity: fewer moving parts; great for prototyping.

Convex tradeoffs

• Less SQL flexibility: you're not living in raw Postgres.
• Vendor-specific workflows: Convex functions and query model are unique.
• Ecosystem depth: fewer extensions and third-party tools.

Best-fit Convex use cases

• Multi-agent apps with realtime dashboards and status boards.
• Early-stage products prioritizing speed and clarity — like the approach in our 3-app build diary.
• Teams that want to avoid managing migrations and infra complexity.

Supabase: Postgres + platform primitives

Supabase is a Postgres-first platform with auth, realtime, and storage. It's closer to the metal but still provides a managed experience.

Where Supabase shines

• Full SQL control: schema design, indexing, and advanced queries.
• Auth and row-level security: solid primitives for multi-tenant agents.
• Ecosystem compatibility: Postgres tooling, backups, extensions.
• Long-term flexibility: easier to migrate or integrate with other systems.

Supabase tradeoffs

• More moving parts: schema design, migrations, and query optimization are on you.
• Realtime limitations: powerful, but you need to design around it.
• Operational overhead: more decisions and surface area for mistakes.

Best-fit Supabase use cases

• Agent platforms with complex relational data models.
• Teams that need SQL power and deep control.
• Products that might outgrow a more opinionated backend.

Realtime: how the two feel in practice

Agent apps often need realtime updates: run status, new tasks, errors, and "human in the loop" signals.

Convex realtime

Convex's realtime queries are the default. Build a dashboard and it updates as data changes. This is excellent for orchestrating agent activity and showing progress to humans.

Supabase realtime

Supabase offers realtime via Postgres changes, but you need to decide how you'll subscribe, which tables to expose, and how to manage scale. It works, but it is more explicit and requires more design.

If your app is realtime-first, Convex feels smoother. If realtime is a secondary feature, Supabase can be enough.

Auth and tenancy

Agent apps often involve multiple roles: admins, operators, end users, and sometimes autonomous agents with scoped permissions.

Convex auth

Convex integrates auth, but it's more opinionated and you may use a provider alongside it. The workflow is smooth, but you'll need to confirm it fits your identity stack.

Supabase auth

Supabase has robust auth out of the box plus row-level security (RLS). This is strong for multi-tenant scenarios where you want strict data separation.

If your app needs complex tenant policies, Supabase's RLS gives you a lot of power.

Database and "memory" design for agents

Agents generate logs, traces, tool calls, and intermediate state.

Convex approach

Convex is good for structured document-like data and event-driven updates. If your "agent memory" is mostly structured logs and you want reactive reads, it's a good fit.

Supabase approach

Supabase shines if you want a well-modeled relational system with joins, indexes, and custom analytics. It's better for long-term retention, analytics, and reporting.

Practical pros and cons

Convex - pros

• Realtime is default
• Functions and data tightly integrated
• Fast prototyping and fewer moving pieces
• Guardrails for consistency

Convex - cons

• More opinionated stack
• Less raw SQL flexibility
• Smaller ecosystem

Supabase - pros

• Full Postgres control
• Strong auth and RLS
• Mature ecosystem
• Easier long-term portability

Supabase - cons

• More operational decisions
• Realtime requires extra design
• More room for schema mistakes

When to choose each (practical scenarios)

Choose Convex if:

• You want a "batteries-included" realtime backend.
• Your agent app is event-driven and needs live updates.
• Your team wants to avoid heavy database operations early on.

Choose Supabase if:

• You need deep SQL control and long-term data flexibility.
• You're modeling complex relationships between users, tasks, and runs.
• You want portability and tooling around Postgres.

Choose both (hybrid patterns)

Some teams use Convex for realtime task orchestration and Supabase for durable storage and analytics. This can work, but be honest about the extra integration cost.

Builder tips for either stack

• Design your agent logs early: define run, step, and tool-call tables/collections.
• Guardrails matter: build soft-delete and validation to prevent agent drift.
• Keep an operator view: your team needs to debug agent behavior quickly.

Decision checklist

• Do we need realtime updates as a core feature? → Convex
• Do we need deep SQL control and relational modeling? → Supabase
• Is our team allergic to DB ops? → Convex
• Are we building long-term analytics and reporting? → Supabase
• Are we willing to run a hybrid architecture? → Maybe both

Final take

Convex is the fast path to a realtime-first agent backend. Supabase is the flexible, SQL-native path for teams that want long-term control. Your choice should be shaped by how much you want to design your data model versus how much you want the platform to do it for you.

The AI Product Building course walks through building with both stacks in depth. If you choose Convex, the Next.js + Convex stack guide covers the full architecture for AI apps. The AI Product Building course walks through building and shipping with this stack end to end. For hands‑on setup, the Convex auth tutorial walks through authentication step by step, and the deployment tutorial covers shipping to production with Vercel.