DeltaBase with Alchemy

Manage DeltaBase event stores and webhook subscriptions from alchemy.run.ts

If your project already uses Alchemy.run, keep DeltaBase there too.

This guide shows how to create event stores and webhook subscriptions with @delta-base/alchemy so your DeltaBase control plane lives beside the rest of your infrastructure.

When to use this

Use this guide when:

you already deploy infra with alchemy.run.ts
you want DeltaBase resources reconciled with the same deploy
you prefer reusable TypeScript resources over a separate CLI config file

If you want DeltaBase-only infrastructure and nothing else, the CLI IaC guide is simpler.

1. Install the packages

pnpm add @delta-base/alchemy alchemy @delta-base/server

Why @delta-base/server too?

Because @delta-base/alchemy builds on the same public SDK you use elsewhere. Less drift. Fewer surprises.

2. Create an `alchemy.run.ts`

import alchemy from 'alchemy';
import {
  DeltaBaseEventStore,
  DeltaBaseSubscription,
} from '@delta-base/alchemy';

const app = await alchemy('billing');

const baseUrl = process.env.DELTABASE_URL ?? 'https://api.delta-base.com';
const apiKey = process.env.DELTABASE_API_KEY ?? '';
const projectionToken = process.env.PROJECTION_AUTH_TOKEN ?? '';

const billingStore = await DeltaBaseEventStore('billing-events', {
  baseUrl,
  apiKey,
  description: 'Billing service event store',
  settings: {
    retentionPeriodDays: 365,
  },
});

await DeltaBaseSubscription('invoice-projection', {
  baseUrl,
  apiKey,
  eventStoreName: billingStore.eventStoreName,
  eventFilter: ['invoice.created', 'invoice.paid'],
  webhook: {
    url: 'https://billing.example.com/api/projections/invoices/events',
    headers: {
      Authorization: `Bearer ${projectionToken}`,
    },
    retryPolicy: {
      strategy: 'fixed',
      maxAttempts: 5,
      initialDelayMs: 60_000,
      maxDelayMs: 60_000,
    },
  },
});

await app.finalize();

That’s the core flow.

DeltaBaseEventStore reconciles the event store
DeltaBaseSubscription reconciles a webhook subscriber for that store
app.finalize() tells Alchemy to finish the deployment and clean up anything orphaned

3. Deploy it

pnpm alchemy deploy ./alchemy.run.ts

Or for local Alchemy development:

pnpm alchemy dev ./alchemy.run.ts

What gets reconciled

Event stores

DeltaBaseEventStore will:

create the store if it does not exist
update description and settings if they drift
delete the store when the resource is removed

Subscriptions

DeltaBaseSubscription will:

create a webhook subscription if it does not exist
update the event filter and webhook config when they change
delete the subscription when the resource is removed

Webhook only for now. That’s intentional.

Things to know before you use it

`subscriberId` is stable

If you set subscriberId, treat it like infrastructure identity. Changing it later means making a new resource.

`eventStoreName` is not mutable

Move a subscription to a different store by creating a new resource. Don’t try to repoint the old one.

Keep secrets out of git

Use environment variables or Alchemy secrets for tokens and API keys.

const apiKey = process.env.DELTABASE_API_KEY ?? '';

Normalize webhook URLs

The resource normalizes extra trailing slashes for you. Still, give it the real endpoint you expect to run in prod.

Alchemy docs worth reading

Those explain how custom resources work and why app.finalize() matters.