diff --git a/packages/db/src/config.ts b/packages/db/src/config.ts
index 9e6956cab3..0336f9af99 100644
--- a/packages/db/src/config.ts
+++ b/packages/db/src/config.ts
@@ -1,6 +1,6 @@
 import type { SQLiteInsertValue } from 'drizzle-orm/sqlite-core';
 import type { SqliteDB, Table } from './internal.js';
-import type { MaybeArray, collectionSchema } from './types.js';
+import type { DBCollection, MaybeArray, collectionSchema } from './types.js';
 import {
 	type BooleanField,
 	type DBFieldInput,
@@ -9,15 +9,14 @@ import {
 	type NumberField,
 	type TextField,
 	collectionsSchema,
+	type indexSchema,
 	type MaybePromise,
 } from './types.js';
 import { z } from 'zod';
 
-export type DBFieldsConfig = z.input<typeof collectionSchema>['fields'];
-
 export type DBDataContext = {
 	db: SqliteDB;
-	seed<TFields extends DBFieldsConfig>(
+	seed<TFields extends FieldsConfig>(
 		collection: ResolvedCollectionConfig<TFields>,
 		data: MaybeArray<
 			SQLiteInsertValue<
@@ -25,7 +24,7 @@ export type DBDataContext = {
 					string,
 					/** TODO: true type inference */ Record<
 						Extract<keyof TFields, string>,
-						DBFieldsConfig[number]
+						FieldsConfig[number]
 					>
 				>
 			>
@@ -51,26 +50,36 @@ export const astroConfigWithDbSchema = z.object({
 	db: dbConfigSchema.optional(),
 });
 
-type CollectionMeta<TFields extends DBFieldsConfig> = {
+export type FieldsConfig = z.input<typeof collectionSchema>['fields'];
+
+type CollectionMeta<TFields extends FieldsConfig> = {
 	// Collection table is set later when running the data() function.
 	// Collection config is assigned to an object key,
 	// so the collection itself does not know the table name.
 	table: Table<string, TFields>;
 };
 
-type CollectionConfig<TFields extends DBFieldsConfig> = {
+interface CollectionConfig<TFields extends FieldsConfig>
+	// use `extends` to ensure types line up with zod,
+	// only adding generics for type completions.
+	extends Pick<z.input<typeof collectionSchema>, 'fields' | 'indexes'> {
 	fields: TFields;
-};
+	indexes?: Record<string, IndexConfig<TFields>>;
+}
+
+interface IndexConfig<TFields extends FieldsConfig> extends z.input<typeof indexSchema> {
+	on: MaybeArray<Extract<keyof TFields, string>>;
+}
 
 export type ResolvedCollectionConfig<
-	TFields extends DBFieldsConfig = DBFieldsConfig,
+	TFields extends FieldsConfig = FieldsConfig,
 	Writable extends boolean = boolean,
 > = CollectionConfig<TFields> & {
 	writable: Writable;
 	table: Table<string, TFields>;
 };
 
-export function defineCollection<TFields extends DBFieldsConfig>(
+export function defineCollection<TFields extends FieldsConfig>(
 	userConfig: CollectionConfig<TFields>
 ): ResolvedCollectionConfig<TFields, false> {
 	const meta: CollectionMeta<TFields> = { table: null! };
@@ -88,7 +97,7 @@ export function defineCollection<TFields extends DBFieldsConfig>(
 	};
 }
 
-export function defineWritableCollection<TFields extends DBFieldsConfig>(
+export function defineWritableCollection<TFields extends FieldsConfig>(
 	userConfig: CollectionConfig<TFields>
 ): ResolvedCollectionConfig<TFields, true> {
 	const meta: CollectionMeta<TFields> = { table: null! };
diff --git a/packages/db/src/types.ts b/packages/db/src/types.ts
index ff580bafd8..510d99ea3a 100644
--- a/packages/db/src/types.ts
+++ b/packages/db/src/types.ts
@@ -52,18 +52,25 @@ const fieldSchema = z.union([
 ]);
 const fieldsSchema = z.record(fieldSchema);
 
-export const readableCollectionSchema = z.object({
+export const indexSchema = z.object({
+	on: z.string().or(z.array(z.string())),
+	unique: z.boolean().optional(),
+});
+const indexesSchema = z.record(indexSchema);
+
+const baseCollectionSchema = z.object({
 	fields: fieldsSchema,
-	writable: z.literal(false),
+	indexes: indexesSchema.optional(),
 	table: z.any(),
 	_setMeta: z.function().optional(),
 });
 
-export const writableCollectionSchema = z.object({
-	fields: fieldsSchema,
+export const readableCollectionSchema = baseCollectionSchema.extend({
+	writable: z.literal(false),
+});
+
+export const writableCollectionSchema = baseCollectionSchema.extend({
 	writable: z.literal(true),
-	table: z.any(),
-	_setMeta: z.function().optional(),
 });
 
 export const collectionSchema = z.union([readableCollectionSchema, writableCollectionSchema]);
diff --git a/packages/db/test/fixtures/recipes/astro.config.ts b/packages/db/test/fixtures/recipes/astro.config.ts
index fd09536894..0a8eedbae2 100644
--- a/packages/db/test/fixtures/recipes/astro.config.ts
+++ b/packages/db/test/fixtures/recipes/astro.config.ts
@@ -16,6 +16,9 @@ const Ingredient = defineCollection({
 		quantity: field.number(),
 		recipeId: field.text(),
 	},
+	indexes: {
+		recipeIdx: { on: 'recipeId', unique: true },
+	},
 });
 
 export default defineConfig({