Connect Amazon RDS or Aurora to your AI agent

RDS is the case where where Midplane runs matters most. A managed Postgres inside a private VPC is unreachable from anything outside it by design — which is usually the point. This page covers both answers: making an RDS instance reachable from Midplane Cloud, and running Midplane inside the VPC when it shouldn’t be. Once connected, your agent reaches RDS only through Midplane: every statement is parsed, checked against policy, and written to the audit trail before it runs.

Pick where Midplane runs

Cloud
Self-host

Midplane Cloud connects over the public internet, so this path fits an instance that already has a public endpoint — commonly a dev or staging instance. It requires all of:

Publicly accessible set to Yes on the instance (Connectivity & security in the RDS console).
The instance’s subnets are public — a route table with a route to an internet gateway.
A security group inbound rule allowing TCP on your database port.

Don’t open a security group to 0.0.0.0/0 to make this work. Midplane Cloud doesn’t publish a fixed egress IP range, so there’s no narrower CIDR that would admit Midplane and nothing else — exposing the instance to every address on the internet is the only rule that would work, and it isn’t worth it for a database you care about.For an instance that isn’t already public, use the self-host tab. It’s the supported answer, and the database stays where it is.

A private instance isn’t blocked at save time, since the connection string is only shape-checked. It fails when an agent first queries, and Test connection reports Could not connect. Check the host, port, and that the database accepts connections from the internet.

Use the right endpoint

RDS and Aurora hand you more than one hostname, and the choice is a safety control in its own right.

Endpoint	When to use it
Aurora reader endpoint	An agent that only reads. The reader physically rejects writes, so a policy gap alone isn’t enough to modify anything.
RDS read replica	Same idea outside Aurora — give the agent the replica’s own endpoint.
Instance or cluster writer endpoint	Only when the agent genuinely needs to write.

Pointing an analysis agent at a reader is the cheapest safety win available here: table access is your policy ceiling, and the replica is a second, physical floor underneath it.

Create a least-privilege role

Don’t use the master user — it holds rds_superuser, and Midplane operates on top of whatever privileges the connection carries. Connect as the master user once, then:

CREATE ROLE midplane LOGIN PASSWORD 'a-strong-password';
GRANT CONNECT ON DATABASE app TO midplane;
GRANT USAGE ON SCHEMA public TO midplane;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO midplane;
ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES TO midplane;

IAM database authentication doesn’t fit. IAM auth issues a token that expires after 15 minutes, and Midplane stores one encrypted connection string per database. Use password authentication for the Midplane role, and rotate it from the credential pane when you need to.

TLS

Check rds.force_ssl in your parameter group. Set to 1, RDS rejects any connection that isn’t encrypted — so a connection string without sslmode will fail at connect time rather than silently downgrade.

postgres://midplane:PASSWORD@mydb.abc123.eu-central-1.rds.amazonaws.com:5432/app?sslmode=require

sslmode=require encrypts without verifying the certificate (libpq semantics, since engine 0.15.0). To verify against Amazon’s CA, download the global RDS trust bundle and point at it:

...?sslmode=verify-full&sslrootcert=/path/to/global-bundle.pem

On Cloud there’s no filesystem to place that bundle on, so sslmode=require is the practical setting there; self-host can mount it and use verify-full. See connecting to your Postgres for the failure modes.

Get started

Core concepts

Connect your database

Connect your agent

Writing policies

Cloud

Run it yourself

Security

Resources

Connect Amazon RDS or Aurora to your AI agent

Pick where Midplane runs

Use the right endpoint

Create a least-privilege role

TLS

Next steps

Deploy self-host

Write a policy

​Pick where Midplane runs

​Use the right endpoint

​Create a least-privilege role

​TLS

​Next steps

Deploy self-host

Write a policy

Pick where Midplane runs

Use the right endpoint

Create a least-privilege role

TLS

Next steps