diff --git a/packages/core/src/app/init.ts b/packages/core/src/app/init.ts
index 0a52826a8..5dfd858c5 100644
--- a/packages/core/src/app/init.ts
+++ b/packages/core/src/app/init.ts
@@ -38,7 +38,7 @@ export default async function initApp(app: Koa): Promise<void> {
   app.use(koaConnectorErrorHandler());
   app.use(koaI18next());
 
-  const provider = await initOidc(app);
+  const provider = initOidc(app);
   initRouter(app, provider);
 
   app.use(mount('/', koaRootProxy()));
diff --git a/packages/core/src/env-set/create-pool-by-env.ts b/packages/core/src/env-set/create-pool-by-env.ts
deleted file mode 100644
index 5d033d34b..000000000
--- a/packages/core/src/env-set/create-pool-by-env.ts
+++ /dev/null
@@ -1,42 +0,0 @@
-import { assert, assertEnv } from '@silverhand/essentials';
-import chalk from 'chalk';
-import { createMockPool, createMockQueryResult, createPool, parseDsn } from 'slonik';
-import { createInterceptors } from 'slonik-interceptor-preset';
-
-const createPoolByEnv = async (isTest: boolean) => {
-  // Database connection is disabled in unit test environment
-  if (isTest) {
-    return createMockPool({ query: async () => createMockQueryResult([]) });
-  }
-
-  const key = 'DB_URL';
-  const interceptors = [...createInterceptors()];
-
-  try {
-    const databaseDsn = assertEnv(key);
-    assert(parseDsn(databaseDsn).databaseName, new Error('Database name is required in `DB_URL`'));
-
-    return await createPool(databaseDsn, { interceptors });
-  } catch (error: unknown) {
-    if (error instanceof Error && error.message === `env variable ${key} not found`) {
-      console.error(
-        `${chalk.red('[error]')} No Postgres DSN (${chalk.green(
-          key
-        )}) found in env variables.\n\n` +
-          `  Either provide it in your env, or add it to the ${chalk.blue(
-            '.env'
-          )} file in the Logto project root.\n\n` +
-          `  If you want to set up a new Logto database, run ${chalk.green(
-            'npm run cli db seed'
-          )} before setting env ${chalk.green(key)}.\n\n` +
-          `  Visit ${chalk.blue(
-            'https://docs.logto.io/docs/references/core/configuration'
-          )} for more info about setting up env.\n`
-      );
-    }
-
-    throw error;
-  }
-};
-
-export default createPoolByEnv;
diff --git a/packages/core/src/env-set/create-pool.ts b/packages/core/src/env-set/create-pool.ts
new file mode 100644
index 000000000..625b9dd12
--- /dev/null
+++ b/packages/core/src/env-set/create-pool.ts
@@ -0,0 +1,18 @@
+import { assert } from '@silverhand/essentials';
+import { createMockPool, createMockQueryResult, createPool, parseDsn } from 'slonik';
+import { createInterceptors } from 'slonik-interceptor-preset';
+
+const createPoolByEnv = async (databaseDsn: string, isTest: boolean) => {
+  // Database connection is disabled in unit test environment
+  if (isTest) {
+    return createMockPool({ query: async () => createMockQueryResult([]) });
+  }
+
+  const interceptors = [...createInterceptors()];
+
+  assert(parseDsn(databaseDsn).databaseName, new Error('Database name is required'));
+
+  return createPool(databaseDsn, { interceptors });
+};
+
+export default createPoolByEnv;
diff --git a/packages/core/src/env-set/create-query-client-by-env.ts b/packages/core/src/env-set/create-query-client-by-env.ts
deleted file mode 100644
index cb950c5b1..000000000
--- a/packages/core/src/env-set/create-query-client-by-env.ts
+++ /dev/null
@@ -1,43 +0,0 @@
-import { assert, assertEnv } from '@silverhand/essentials';
-import { PostgresQueryClient } from '@withtyped/postgres';
-import chalk from 'chalk';
-import { parseDsn } from 'slonik';
-
-import { MockQueryClient } from '#src/test-utils/query-client.js';
-
-const createQueryClientByEnv = (isTest: boolean) => {
-  // Database connection is disabled in unit test environment
-  if (isTest) {
-    return new MockQueryClient();
-  }
-
-  const key = 'DB_URL';
-
-  try {
-    const databaseDsn = assertEnv(key);
-    assert(parseDsn(databaseDsn), new Error('Database name is required in `DB_URL`'));
-
-    return new PostgresQueryClient({ connectionString: databaseDsn });
-  } catch (error: unknown) {
-    if (error instanceof Error && error.message === `env variable ${key} not found`) {
-      console.error(
-        `${chalk.red('[error]')} No Postgres DSN (${chalk.green(
-          key
-        )}) found in env variables.\n\n` +
-          `  Either provide it in your env, or add it to the ${chalk.blue(
-            '.env'
-          )} file in the Logto project root.\n\n` +
-          `  If you want to set up a new Logto database, run ${chalk.green(
-            'npm run cli db seed'
-          )} before setting env ${chalk.green(key)}.\n\n` +
-          `  Visit ${chalk.blue(
-            'https://docs.logto.io/docs/references/core/configuration'
-          )} for more info about setting up env.\n`
-      );
-    }
-
-    throw error;
-  }
-};
-
-export default createQueryClientByEnv;
diff --git a/packages/core/src/env-set/create-query-client.ts b/packages/core/src/env-set/create-query-client.ts
new file mode 100644
index 000000000..f091214e9
--- /dev/null
+++ b/packages/core/src/env-set/create-query-client.ts
@@ -0,0 +1,18 @@
+import { assert } from '@silverhand/essentials';
+import { PostgresQueryClient } from '@withtyped/postgres';
+import { parseDsn } from 'slonik';
+
+import { MockQueryClient } from '#src/test-utils/query-client.js';
+
+const createQueryClient = (databaseDsn: string, isTest: boolean) => {
+  // Database connection is disabled in unit test environment
+  if (isTest) {
+    return new MockQueryClient();
+  }
+
+  assert(parseDsn(databaseDsn), new Error('Database name is required'));
+
+  return new PostgresQueryClient({ connectionString: databaseDsn });
+};
+
+export default createQueryClient;
diff --git a/packages/core/src/env-set/dot-env.ts b/packages/core/src/env-set/dot-env.ts
deleted file mode 100644
index f95cd2b9f..000000000
--- a/packages/core/src/env-set/dot-env.ts
+++ /dev/null
@@ -1,12 +0,0 @@
-import { appendFileSync } from 'fs';
-
-import dotenv from 'dotenv';
-import { findUp } from 'find-up';
-
-export const appendDotEnv = (key: string, value: string) => {
-  appendFileSync('.env', `${key}=${value}\n`);
-};
-
-export const configDotEnv = async () => {
-  dotenv.config({ path: await findUp('.env', {}) });
-};
diff --git a/packages/core/src/env-set/index.ts b/packages/core/src/env-set/index.ts
index 5f1a775d1..da291b052 100644
--- a/packages/core/src/env-set/index.ts
+++ b/packages/core/src/env-set/index.ts
@@ -1,5 +1,6 @@
+import { tryThat } from '@logto/shared';
 import type { Optional } from '@silverhand/essentials';
-import { getEnv, getEnvAsStringArray } from '@silverhand/essentials';
+import { assertEnv, getEnv, getEnvAsStringArray } from '@silverhand/essentials';
 import type { PostgreSql } from '@withtyped/postgres';
 import type { QueryClient } from '@withtyped/server';
 import type { DatabasePool } from 'slonik';
@@ -8,10 +9,11 @@ import { getOidcConfigs } from '#src/libraries/logto-config.js';
 import { appendPath } from '#src/utils/url.js';
 
 import { checkAlterationState } from './check-alteration-state.js';
-import createPoolByEnv from './create-pool-by-env.js';
-import createQueryClientByEnv from './create-query-client-by-env.js';
+import createPool from './create-pool.js';
+import createQueryClient from './create-query-client.js';
 import loadOidcValues from './oidc.js';
 import { isTrue } from './parameters.js';
+import { throwErrorWithDsnMessage, throwNotLoadedError } from './throw-errors.js';
 
 export enum MountedApps {
   Api = 'api',
@@ -21,7 +23,7 @@ export enum MountedApps {
   Welcome = 'welcome',
 }
 
-const loadEnvValues = async () => {
+const loadEnvValues = () => {
   const isProduction = getEnv('NODE_ENV') === 'production';
   const isTest = getEnv('NODE_ENV') === 'test';
   const isIntegrationTest = isTrue(getEnv('INTEGRATION_TEST'));
@@ -29,6 +31,7 @@ const loadEnvValues = async () => {
   const port = Number(getEnv('PORT', '3001'));
   const localhostUrl = `${isHttpsEnabled ? 'https' : 'http'}://localhost:${port}`;
   const endpoint = getEnv('ENDPOINT', localhostUrl);
+  const databaseUrl = tryThat(() => assertEnv('DB_URL'), throwErrorWithDsnMessage);
 
   return Object.freeze({
     isTest,
@@ -40,6 +43,7 @@ const loadEnvValues = async () => {
     port,
     localhostUrl,
     endpoint,
+    dbUrl: databaseUrl,
     userDefaultRoleNames: getEnvAsStringArray('USER_DEFAULT_ROLE_NAMES'),
     developmentUserId: getEnv('DEVELOPMENT_USER_ID'),
     trustProxyHeader: isTrue(getEnv('TRUST_PROXY_HEADER')),
@@ -47,68 +51,71 @@ const loadEnvValues = async () => {
   });
 };
 
-const throwNotLoadedError = () => {
-  throw new Error(
-    'The env set is not loaded. Make sure to call `await envSet.load()` before using it.'
-  );
-};
+class EnvSet {
+  static envValues: ReturnType<typeof loadEnvValues> = loadEnvValues();
 
-/* eslint-disable @silverhand/fp/no-let, @silverhand/fp/no-mutation */
-function createEnvSet() {
-  let values: Optional<Awaited<ReturnType<typeof loadEnvValues>>>;
-  let pool: Optional<DatabasePool>;
+  #pool: Optional<DatabasePool>;
   // Use another pool for `withtyped` while adopting the new model,
   // as we cannot extract the original PgPool from slonik
-  let queryClient: Optional<QueryClient<PostgreSql>>;
-  let oidc: Optional<Awaited<ReturnType<typeof loadOidcValues>>>;
+  #queryClient: Optional<QueryClient<PostgreSql>>;
+  #oidc: Optional<Awaited<ReturnType<typeof loadOidcValues>>>;
 
-  return {
-    get values() {
-      if (!values) {
-        return throwNotLoadedError();
-      }
+  constructor(public readonly databaseUrl = EnvSet.envValues.dbUrl) {}
 
-      return values;
-    },
-    get pool() {
-      if (!pool) {
-        return throwNotLoadedError();
-      }
+  get values() {
+    return EnvSet.envValues;
+  }
 
-      return pool;
-    },
-    get poolSafe() {
-      return pool;
-    },
-    get queryClient() {
-      if (!queryClient) {
-        return throwNotLoadedError();
-      }
+  get isTest() {
+    return EnvSet.envValues.isTest;
+  }
 
-      return queryClient;
-    },
-    get queryClientSafe() {
-      return queryClient;
-    },
-    get oidc() {
-      if (!oidc) {
-        return throwNotLoadedError();
-      }
+  get pool() {
+    if (!this.#pool) {
+      return throwNotLoadedError();
+    }
 
-      return oidc;
-    },
-    load: async () => {
-      values = await loadEnvValues();
-      pool = await createPoolByEnv(values.isTest);
-      queryClient = createQueryClientByEnv(values.isTest);
+    return this.#pool;
+  }
 
-      const [, oidcConfigs] = await Promise.all([checkAlterationState(pool), getOidcConfigs(pool)]);
-      oidc = await loadOidcValues(appendPath(values.endpoint, '/oidc').toString(), oidcConfigs);
-    },
-  };
+  get poolSafe() {
+    return this.#pool;
+  }
+
+  get queryClient() {
+    if (!this.#queryClient) {
+      return throwNotLoadedError();
+    }
+
+    return this.#queryClient;
+  }
+
+  get queryClientSafe() {
+    return this.#queryClient;
+  }
+
+  get oidc() {
+    if (!this.#oidc) {
+      return throwNotLoadedError();
+    }
+
+    return this.#oidc;
+  }
+
+  async load() {
+    const pool = await createPool(this.databaseUrl, this.isTest);
+
+    this.#pool = pool;
+    this.#queryClient = createQueryClient(this.databaseUrl, this.isTest);
+
+    const [, oidcConfigs] = await Promise.all([checkAlterationState(pool), getOidcConfigs(pool)]);
+    this.#oidc = await loadOidcValues(
+      appendPath(this.values.endpoint, '/oidc').toString(),
+      oidcConfigs
+    );
+  }
 }
-/* eslint-enable @silverhand/fp/no-let, @silverhand/fp/no-mutation */
 
-const envSet = createEnvSet();
+const envSet = new EnvSet();
 
 export default envSet;
diff --git a/packages/core/src/env-set/throw-errors.ts b/packages/core/src/env-set/throw-errors.ts
new file mode 100644
index 000000000..a3ab6ef09
--- /dev/null
+++ b/packages/core/src/env-set/throw-errors.ts
@@ -0,0 +1,28 @@
+import chalk from 'chalk';
+
+export const throwNotLoadedError = () => {
+  throw new Error(
+    'The env set is not loaded. Make sure to call `await envSet.load()` before using it.'
+  );
+};
+
+export const throwErrorWithDsnMessage = (error: unknown) => {
+  const key = 'DB_URL';
+
+  if (error instanceof Error && error.message === `env variable ${key} not found`) {
+    console.error(
+      `${chalk.red('[error]')} No Postgres DSN (${chalk.green(key)}) found in env variables.\n\n` +
+        `  Either provide it in your env, or add it to the ${chalk.blue(
+          '.env'
+        )} file in the Logto project root.\n\n` +
+        `  If you want to set up a new Logto database, run ${chalk.green(
+          'npm run cli db seed'
+        )} before setting env ${chalk.green(key)}.\n\n` +
+        `  Visit ${chalk.blue(
+          'https://docs.logto.io/docs/references/core/configuration'
+        )} for more info about setting up env.\n`
+    );
+  }
+
+  throw error;
+};
diff --git a/packages/core/src/index.ts b/packages/core/src/index.ts
index 8c7e8f903..ad51c7755 100644
--- a/packages/core/src/index.ts
+++ b/packages/core/src/index.ts
@@ -1,14 +1,19 @@
 import { noop } from '@silverhand/essentials';
+import dotenv from 'dotenv';
+import { findUp } from 'find-up';
 import Koa from 'koa';
 
-import { loadConnectorFactories } from './connectors/index.js';
-import { configDotEnv } from './env-set/dot-env.js';
-import envSet from './env-set/index.js';
 import initI18n from './i18n/init.js';
 
+dotenv.config({ path: await findUp('.env', {}) });
+
+// Import after env has configured
+const { default: envSet } = await import('./env-set/index.js');
+await envSet.load();
+
+const { loadConnectorFactories } = await import('./connectors/index.js');
+
 try {
-  await configDotEnv();
-  await envSet.load();
   const app = new Koa({
     proxy: envSet.values.trustProxyHeader,
   });
diff --git a/packages/core/src/libraries/hook.test.ts b/packages/core/src/libraries/hook.test.ts
index a1e2f119f..c23701718 100644
--- a/packages/core/src/libraries/hook.test.ts
+++ b/packages/core/src/libraries/hook.test.ts
@@ -48,7 +48,7 @@ mockEsm('#src/queries/application.js', () => ({
 }));
 
 // eslint-disable-next-line unicorn/consistent-function-scoping
-mockEsmDefault('#src/env-set/create-query-client-by-env.js', () => () => queryClient);
+mockEsmDefault('#src/env-set/create-query-client.js', () => () => queryClient);
 jest.spyOn(queryClient, 'query').mockImplementation(queryFunction);
 
 const { triggerInteractionHooksIfNeeded } = await import('./hook.js');
diff --git a/packages/core/src/oidc/init.test.ts b/packages/core/src/oidc/init.test.ts
index 6973dd129..b16a2949f 100644
--- a/packages/core/src/oidc/init.test.ts
+++ b/packages/core/src/oidc/init.test.ts
@@ -5,6 +5,6 @@ import initOidc from './init.js';
 describe('oidc provider init', () => {
   it('init should not throw', async () => {
     const app = new Koa();
-    await expect(initOidc(app)).resolves.not.toThrow();
+    expect(() => initOidc(app)).not.toThrow();
   });
 });
diff --git a/packages/core/src/oidc/init.ts b/packages/core/src/oidc/init.ts
index cf58f11ba..47070199f 100644
--- a/packages/core/src/oidc/init.ts
+++ b/packages/core/src/oidc/init.ts
@@ -23,7 +23,7 @@ import assertThat from '#src/utils/assert-that.js';
 
 import { claimToUserKey, getUserClaims } from './scope.js';
 
-export default async function initOidc(app: Koa): Promise<Provider> {
+export default function initOidc(app: Koa): Provider {
   const { issuer, cookieKeys, privateJwks, defaultIdTokenTtl, defaultRefreshTokenTtl } =
     envSet.oidc;
   const logoutSource = readFileSync('static/html/logout.html', 'utf8');
diff --git a/packages/shared/src/utils/function.test.ts b/packages/shared/src/utils/function.test.ts
index 7ddd797bd..44a5af294 100644
--- a/packages/shared/src/utils/function.test.ts
+++ b/packages/shared/src/utils/function.test.ts
@@ -1,9 +1,56 @@
-import { trySafe } from './function.js';
+import { trySafe, tryThat } from './function.js';
+
+describe('tryThat()', () => {
+  it('should directly execute and return or throw if the function is not a Promise', () => {
+    expect(tryThat(() => 'foo', new Error('try'))).toStrictEqual('foo');
+    expect(() =>
+      tryThat(() => {
+        throw new Error('Test');
+      }, new Error('try'))
+    ).toThrowError(new Error('try'));
+    expect(() =>
+      tryThat(
+        () => {
+          throw new Error('Test');
+        },
+        (error) => {
+          throw new Error(String(error instanceof Error && error.message) + ' try');
+        }
+      )
+    ).toThrowError(new Error('Test try'));
+  });
+
+  it('should execute or unwrap a Promise and throw the error', async () => {
+    expect(
+      await tryThat(
+        new Promise((resolve) => {
+          setTimeout(() => {
+            resolve('bar');
+          }, 0);
+        }),
+        new Error('try')
+      )
+    ).toStrictEqual('bar');
+
+    await expect(
+      tryThat(
+        async () =>
+          new Promise((resolve, reject) => {
+            reject();
+          }),
+        () => {
+          throw new Error('try');
+        }
+      )
+    ).rejects.toStrictEqual(new Error('try'));
+  });
+});
 
 describe('trySafe()', () => {
   it('should directly execute and return if the function is not a Promise', () => {
     expect(trySafe(() => 'foo')).toStrictEqual('foo');
     expect(
+      // eslint-disable-next-line @typescript-eslint/no-confusing-void-expression
       trySafe(() => {
         throw new Error('Test');
       })
diff --git a/packages/shared/src/utils/function.ts b/packages/shared/src/utils/function.ts
index f55dfb727..bc505e37e 100644
--- a/packages/shared/src/utils/function.ts
+++ b/packages/shared/src/utils/function.ts
@@ -1,29 +1,41 @@
-export const tryThat = async <T, E extends Error>(
-  exec: Promise<T> | (() => Promise<T>),
-  onError: E | ((error: unknown) => never)
-): Promise<T> => {
-  try {
-    return await (typeof exec === 'function' ? exec() : exec);
-  } catch (error: unknown) {
-    if (onError instanceof Error) {
-      // https://github.com/typescript-eslint/typescript-eslint/issues/3814
-      // eslint-disable-next-line @typescript-eslint/no-throw-literal
-      throw onError;
-    }
-
-    return onError(error);
-  }
-};
-
 export const isPromise = (value: unknown): value is Promise<unknown> =>
   value !== null &&
   (typeof value === 'object' || typeof value === 'function') &&
   'then' in value &&
   typeof value.then === 'function';
 
+export type TryThat = {
+  <T>(exec: () => T, onError: Error | ((error: unknown) => never)): T;
+  <T>(
+    exec: Promise<T> | (() => Promise<T>),
+    onError: Error | ((error: unknown) => never)
+  ): Promise<T>;
+};
+
+export const tryThat: TryThat = (exec, onError) => {
+  const handleError = (error: unknown) => {
+    if (onError instanceof Error) {
+      throw onError;
+    }
+
+    return onError(error);
+  };
+
+  try {
+    const unwrapped = typeof exec === 'function' ? exec() : exec;
+
+    return isPromise(unwrapped)
+      ? // eslint-disable-next-line promise/prefer-await-to-then
+        unwrapped.catch(handleError)
+      : unwrapped;
+  } catch (error: unknown) {
+    return handleError(error);
+  }
+};
+
 export type TrySafe = {
-  <T>(exec: Promise<T> | (() => Promise<T>)): Promise<T | undefined>;
   <T>(exec: () => T): T | undefined;
+  <T>(exec: Promise<T> | (() => Promise<T>)): Promise<T | undefined>;
 };
 
 export const trySafe: TrySafe = (exec) => {