RDS (parlel emulator)

A zero-dependency, in-process fake of the Amazon RDS control plane. Models DB instance/cluster/snapshot metadata. The data plane backs onto the parlel postgres and mysql emulators.

Property	Value
Port	4721
Protocol	AWS Query/XML (Version 2014-10-31)
Healthcheck	`GET /_parlel/health`
Reset	`POST /_parlel/reset`

Default connection

AWS_REGION=us-east-1
AWS_ENDPOINT_URL=http://127.0.0.1:4721
AWS_ACCESS_KEY_ID=parlel
AWS_SECRET_ACCESS_KEY=parlel

Supported operations

Instances: CreateDBInstance, DescribeDBInstances, DeleteDBInstance, ModifyDBInstance
Clusters: CreateDBCluster, DescribeDBClusters
Snapshots: CreateDBSnapshot, DescribeDBSnapshots

CreateDBInstance returns an Endpoint { Address, Port }. The port defaults to 5432 (postgres family) or 3306 (mysql/maria/aurora-mysql). Point your SQL client at the matching parlel postgres/mysql emulator for the actual data plane.

SDK example

import { RDSClient, CreateDBInstanceCommand } from "@aws-sdk/client-rds";

const rds = new RDSClient({
  region: "us-east-1",
  endpoint: "http://127.0.0.1:4721",
  credentials: { accessKeyId: "parlel", secretAccessKey: "parlel" },
});

const { DBInstance } = await rds.send(new CreateDBInstanceCommand({
  DBInstanceIdentifier: "db1",
  Engine: "postgres",
  DBInstanceClass: "db.t3.micro",
  AllocatedStorage: 20,
  MasterUsername: "admin",
  MasterUserPassword: "secret99",
}));
console.log(DBInstance?.Endpoint); // { Address, Port: 5432 }

Access via MCP / preview URL

Reachable through the parlel pool MCP bridge and preview URL. No auth setup required.

Surface coverage

This emulator faithfully replicates the API surface most application code and agents exercise. Anything below the supported lines is either an intentional design choice for a fast, zero-cost local emulator (✓ By design) or a candidate for a future release (⟳ Roadmap) — never a silent inaccuracy.

Legend: ✅ fully supported · ◐ accepted (stored, not strictly enforced) · ✓ by design · ⟳ on the roadmap.

Area	Limitation
Provisioning	Instances are immediately `available`; no async states.
Data plane	This service is metadata only — use postgres/mysql emulators.
Parameter groups	Not modeled.
Restore	Snapshot restore is not implemented.

Configuration — `test.env`

Copy these into your test.env (used by the bridge sidecar flow). Tokens are Parlel's seeded test credentials — any non-empty value is accepted by the emulator, so you rarely need to change them. Swap in real credentials only when pointing at the live service in prod.env.

AWS_ACCESS_KEY_ID=parlel
AWS_SECRET_ACCESS_KEY=parlel
AWS_REGION=us-east-1
AWS_ENDPOINT_URL=http://parlel-bridge:4721