diff --git a/apps/api/src/__tests__/auth.test.ts b/apps/api/src/__tests__/auth.test.ts
new file mode 100644
index 0000000..7b4db22
--- /dev/null
+++ b/apps/api/src/__tests__/auth.test.ts
@@ -0,0 +1,152 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest";
+
+// Mutable state to control mock behavior per test
+let dbSelectResult: unknown[] = [];
+const mockEq = vi.fn((_col: unknown, _val: unknown) => ({ col: _col, val: _val }));
+const mockDecryptSecret = vi.fn((s: string) => `decrypted:${s}`);
+
+vi.mock("@groombook/db", () => {
+  const authProviderConfig = new Proxy(
+    { _name: "auth_provider_config" },
+    {
+      get(target, prop) {
+        if (prop === "_name") return "auth_provider_config";
+        if (prop === "$inferSelect") return {};
+        return { table: "auth_provider_config", column: prop };
+      },
+    }
+  );
+
+  return {
+    getDb: () => ({
+      select: () => ({
+        from: () => ({
+          where: () => ({
+            limit: () => dbSelectResult,
+            [Symbol.iterator]: function* () {
+              for (const item of dbSelectResult) yield item;
+            },
+            0: dbSelectResult[0],
+            length: dbSelectResult.length,
+          }),
+        }),
+      }),
+    }),
+    authProviderConfig,
+    eq: mockEq,
+    decryptSecret: mockDecryptSecret,
+  };
+});
+
+async function reimportAuth() {
+  vi.resetModules();
+  vi.doMock("@groombook/db", () => ({
+    getDb: () => ({
+      select: () => ({
+        from: () => ({
+          where: () => ({
+            limit: () => dbSelectResult,
+            [Symbol.iterator]: function* () {
+              for (const item of dbSelectResult) yield item;
+            },
+            0: dbSelectResult[0],
+            length: dbSelectResult.length,
+          }),
+        }),
+      }),
+    }),
+    authProviderConfig: {},
+    eq: mockEq,
+    decryptSecret: mockDecryptSecret,
+  }));
+  const mod = await import("../lib/auth.js");
+  return mod;
+}
+
+describe("auth init", () => {
+  const originalEnv = { ...process.env };
+
+  beforeEach(() => {
+    dbSelectResult = [];
+    vi.clearAllMocks();
+  });
+
+  afterEach(() => {
+    process.env = { ...originalEnv };
+  });
+
+  it("falls back to env vars when DB returns empty", async () => {
+    process.env = {
+      ...originalEnv,
+      OIDC_ISSUER: "https://issuer.example.com",
+      OIDC_CLIENT_ID: "test-client-id",
+      OIDC_CLIENT_SECRET: "test-client-secret",
+      BETTER_AUTH_SECRET: "test-secret",
+      BETTER_AUTH_URL: "http://localhost:3000",
+      NODE_ENV: "test",
+    };
+
+    const { initAuth, getAuth } = await reimportAuth();
+    await initAuth();
+    expect(getAuth()).toBeDefined();
+  });
+
+  it("uses DB config and decrypts clientSecret when DB has enabled provider", async () => {
+    const dbConfig = {
+      id: "config-id",
+      providerId: "okta",
+      displayName: "Okta",
+      issuerUrl: "https://okta.example.com",
+      internalBaseUrl: null,
+      clientId: "okta-client-id",
+      clientSecret: "encrypted:okta-secret",
+      scopes: "openid profile email",
+      enabled: true,
+      createdAt: new Date(),
+      updatedAt: new Date(),
+    };
+    dbSelectResult = [dbConfig];
+
+    process.env = {
+      ...originalEnv,
+      BETTER_AUTH_SECRET: "test-secret",
+      BETTER_AUTH_URL: "http://localhost:3000",
+      NODE_ENV: "test",
+    };
+
+    const { initAuth, getAuth } = await reimportAuth();
+    await initAuth();
+    expect(getAuth()).toBeDefined();
+    expect(mockDecryptSecret).toHaveBeenCalledWith("encrypted:okta-secret");
+  });
+
+  it("throws when BETTER_AUTH_SECRET is missing and AUTH_DISABLED is not set", async () => {
+    process.env = {
+      ...originalEnv,
+      OIDC_ISSUER: "",
+      OIDC_CLIENT_ID: "",
+      OIDC_CLIENT_SECRET: "",
+      NODE_ENV: "test",
+    };
+    delete process.env.BETTER_AUTH_SECRET;
+    delete process.env.AUTH_DISABLED;
+
+    const { initAuth } = await reimportAuth();
+    await expect(initAuth()).rejects.toThrow(
+      "[FATAL] BETTER_AUTH_SECRET environment variable is required when auth is enabled"
+    );
+  });
+
+  it("builds placeholder auth when AUTH_DISABLED=true without throwing", async () => {
+    process.env = {
+      ...originalEnv,
+      AUTH_DISABLED: "true",
+      NODE_ENV: "test",
+    };
+    delete process.env.BETTER_AUTH_SECRET;
+
+    const { initAuth, getAuth } = await reimportAuth();
+    await expect(initAuth()).resolves.toBeUndefined();
+    expect(getAuth()).toBeDefined();
+  });
+});
diff --git a/apps/api/src/index.ts b/apps/api/src/index.ts
index e51436b..6fa1df3 100644
--- a/apps/api/src/index.ts
+++ b/apps/api/src/index.ts
@@ -2,7 +2,7 @@ import { serve } from "@hono/node-server";
 import { Hono } from "hono";
 import { logger } from "hono/logger";
 import { cors } from "hono/cors";
-import { auth } from "./lib/auth.js";
+import { getAuth, initAuth } from "./lib/auth.js";
 import { clientsRouter } from "./routes/clients.js";
 import { petsRouter } from "./routes/pets.js";
 import { servicesRouter } from "./routes/services.js";
@@ -99,7 +99,7 @@ api.use("*", resolveStaffMiddleware);
 // Better-Auth handler — mounted as sub-app to handle all /api/auth/* routes
 // authMiddleware and resolveStaffMiddleware both skip /api/auth/ paths
 const authRouter = new Hono();
-authRouter.all("/*", (c) => auth.handler(c.req.raw));
+authRouter.all("/*", (c) => getAuth().handler(c.req.raw));
 api.route("/auth", authRouter);
 
 // ── Role guards ────────────────────────────────────────────────────────────────
@@ -168,6 +168,7 @@ api.route("/admin/seed", adminSeedRouter);
 api.route("/search", searchRouter);
 
 const port = Number(process.env.PORT ?? 3000);
+await initAuth();
 console.log(`API server listening on port ${port}`);
 serve({ fetch: app.fetch, port });
 
diff --git a/apps/api/src/lib/auth.ts b/apps/api/src/lib/auth.ts
index 8467513..b7d285c 100644
--- a/apps/api/src/lib/auth.ts
+++ b/apps/api/src/lib/auth.ts
@@ -1,61 +1,182 @@
 import { betterAuth } from "better-auth";
 import { drizzleAdapter } from "better-auth/adapters/drizzle";
 import { genericOAuth } from "better-auth/plugins";
-import { getDb } from "@groombook/db";
+import { getDb, authProviderConfig, eq } from "@groombook/db";
+import { decryptSecret } from "@groombook/db";
 
-const OIDC_ISSUER = process.env.OIDC_ISSUER;
-const OIDC_INTERNAL_BASE = process.env.OIDC_INTERNAL_BASE; // e.g. http://authentik-server.auth.svc.cluster.local
-const OIDC_CLIENT_ID = process.env.OIDC_CLIENT_ID;
-const OIDC_CLIENT_SECRET = process.env.OIDC_CLIENT_SECRET;
 const BETTER_AUTH_SECRET = process.env.BETTER_AUTH_SECRET;
 const BETTER_AUTH_URL = process.env.BETTER_AUTH_URL ?? "http://localhost:3000";
 
-if (!BETTER_AUTH_SECRET && process.env.AUTH_DISABLED !== "true") {
-  throw new Error(
-    "[FATAL] BETTER_AUTH_SECRET environment variable is required when auth is enabled"
-  );
+// Auth instance — initialized lazily via initAuth()
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+let authInstance: any = null;
+let authInitPromise: Promise<void> | null = null;
+
+/** Returns the current auth instance. Throws if not yet initialized. */
+export function getAuth() {
+  if (!authInstance) {
+    throw new Error(
+      "Auth not initialized. Call initAuth() at startup before handling requests."
+    );
+  }
+  return authInstance;
 }
 
-export const auth = betterAuth({
-  database: drizzleAdapter(getDb(), {
-    provider: "pg",
-  }),
-  secret: BETTER_AUTH_SECRET,
-  baseURL: BETTER_AUTH_URL,
-  plugins: [
-    genericOAuth({
-      config: [
-        {
-          providerId: "authentik",
-          clientId: OIDC_CLIENT_ID ?? "",
-          clientSecret: OIDC_CLIENT_SECRET ?? "",
-          // When OIDC_INTERNAL_BASE is set, use explicit URLs to avoid hairpin NAT:
-          // - authorizationUrl: external (browser redirect, no server-side fetch)
-          // - tokenUrl/userInfoUrl: internal (server-to-server, avoids hairpin)
-          // When not set, fall back to discoveryUrl for local dev.
-          ...(OIDC_INTERNAL_BASE
-            ? {
-                authorizationUrl: `${new URL(OIDC_ISSUER!).origin}/application/o/authorize/`,
-                tokenUrl: `${OIDC_INTERNAL_BASE}/application/o/token/`,
-                userInfoUrl: `${OIDC_INTERNAL_BASE}/application/o/userinfo/`,
-              }
-            : {
-                discoveryUrl: OIDC_ISSUER
-                  ? `${OIDC_ISSUER}/.well-known/openid-configuration`
-                  : undefined,
-              }),
-          scopes: ["openid", "profile", "email"],
+/** Returns a promise that resolves when auth is initialized. */
+export function getAuthPromise() {
+  return authInitPromise;
+}
+
+/**
+ * Initializes the Better-Auth instance.
+ *
+ * Config resolution chain:
+ * 1. Query auth_provider_config table for an enabled provider
+ * 2. If DB config exists → use it (decrypt clientSecret)
+ * 3. If no DB config → fall back to OIDC_* env vars
+ * 4. If neither → auth is unconfigured (getAuth() returns null, AUTH_DISABLED implied)
+ *
+ * Idempotent — subsequent calls return immediately after initialization completes.
+ */
+export async function initAuth(): Promise<void> {
+  if (authInstance) return; // Already initialized
+  if (authInitPromise) {
+    await authInitPromise;
+    return;
+  }
+
+  authInitPromise = (async () => {
+    // Guard: require BETTER_AUTH_SECRET unless explicitly in dev/demo mode
+    if (!BETTER_AUTH_SECRET && process.env.AUTH_DISABLED !== "true") {
+      throw new Error(
+        "[FATAL] BETTER_AUTH_SECRET environment variable is required when auth is enabled"
+      );
+    }
+
+    // AUTH_DISABLED=true means dev/demo mode — still build Better-Auth with placeholder
+    // config so auth.handler exists (middleware bypasses it anyway)
+    if (process.env.AUTH_DISABLED === "true") {
+      console.warn("[auth] AUTH_DISABLED=true — building placeholder auth instance");
+      authInstance = betterAuth({
+        database: drizzleAdapter(getDb(), { provider: "pg" }),
+        secret: BETTER_AUTH_SECRET ?? "placeholder-secret-do-not-use-in-prod",
+        baseURL: BETTER_AUTH_URL,
+        plugins: [
+          genericOAuth({
+            config: [
+              {
+                providerId: "authentik",
+                clientId: "placeholder",
+                clientSecret: "placeholder",
+                discoveryUrl: undefined,
+                scopes: ["openid", "profile", "email"],
+              },
+            ],
+          }),
+        ],
+        session: {
+          expiresIn: 60 * 60 * 24 * 7,
+          updateAge: 60 * 60 * 24,
+          cookieCache: { enabled: false },
         },
+        trustedOrigins: [process.env.CORS_ORIGIN ?? "http://localhost:5173"],
+      });
+      return;
+    }
+
+    // Step 1: Try to load config from DB
+    const db = getDb();
+    const [dbConfig] = await db
+      .select()
+      .from(authProviderConfig)
+      .where(eq(authProviderConfig.enabled, true))
+      .limit(1);
+
+    let providerConfig: {
+      providerId: string;
+      clientId: string;
+      clientSecret: string;
+      issuerUrl: string;
+      internalBaseUrl?: string;
+      scopes: string;
+    };
+
+    if (dbConfig) {
+      // Step 2: Use DB config (decrypt clientSecret)
+      const decryptedSecret = decryptSecret(dbConfig.clientSecret);
+      providerConfig = {
+        providerId: dbConfig.providerId,
+        clientId: dbConfig.clientId,
+        clientSecret: decryptedSecret,
+        issuerUrl: dbConfig.issuerUrl,
+        internalBaseUrl: dbConfig.internalBaseUrl ?? undefined,
+        scopes: dbConfig.scopes,
+      };
+      console.log("[auth] Using DB config for provider:", dbConfig.providerId);
+    } else {
+      // Step 3: Fall back to env vars
+      const oidcIssuer = process.env.OIDC_ISSUER;
+      const oidcClientId = process.env.OIDC_CLIENT_ID;
+      const oidcClientSecret = process.env.OIDC_CLIENT_SECRET;
+
+      if (!oidcIssuer || !oidcClientId || !oidcClientSecret) {
+        // Step 4: Neither DB config nor env vars — auth is unconfigured
+        console.warn(
+          "[auth] No auth provider configured. Set up auth_provider_config in DB or OIDC_* env vars."
+        );
+        return; // authInstance stays null — AUTH_DISABLED mode
+      }
+
+      providerConfig = {
+        providerId: "authentik",
+        clientId: oidcClientId,
+        clientSecret: oidcClientSecret,
+        issuerUrl: oidcIssuer,
+        internalBaseUrl: process.env.OIDC_INTERNAL_BASE,
+        scopes: "openid profile email",
+      };
+      console.log("[auth] Using env var config (no DB config found)");
+    }
+
+    // Build Better-Auth instance using resolved config
+    authInstance = betterAuth({
+      database: drizzleAdapter(db, {
+        provider: "pg",
+      }),
+      secret: BETTER_AUTH_SECRET,
+      baseURL: BETTER_AUTH_URL,
+      plugins: [
+        genericOAuth({
+          config: [
+            {
+              providerId: providerConfig.providerId,
+              clientId: providerConfig.clientId,
+              clientSecret: providerConfig.clientSecret,
+              ...(providerConfig.internalBaseUrl
+                ? {
+                    authorizationUrl: `${new URL(providerConfig.issuerUrl).origin}/application/o/authorize/`,
+                    tokenUrl: `${providerConfig.internalBaseUrl}/application/o/token/`,
+                    userInfoUrl: `${providerConfig.internalBaseUrl}/application/o/userinfo/`,
+                  }
+                : {
+                    discoveryUrl: `${providerConfig.issuerUrl}/.well-known/openid-configuration`,
+                  }),
+              scopes: providerConfig.scopes.split(" ").filter(Boolean),
+            },
+          ],
+        }),
       ],
-    }),
-  ],
-  session: {
-    expiresIn: 60 * 60 * 24 * 7, // 7 days
-    updateAge: 60 * 60 * 24, // 1 day
-    cookieCache: {
-      enabled: true,
-      maxAge: 5 * 60, // 5 minutes
-    },
-  },
-  trustedOrigins: [process.env.CORS_ORIGIN ?? "http://localhost:5173"],
-});
+      session: {
+        expiresIn: 60 * 60 * 24 * 7, // 7 days
+        updateAge: 60 * 60 * 24, // 1 day
+        cookieCache: {
+          enabled: true,
+          maxAge: 5 * 60, // 5 minutes
+        },
+      },
+      trustedOrigins: [process.env.CORS_ORIGIN ?? "http://localhost:5173"],
+    });
+  })();
+
+  await authInitPromise;
+}
diff --git a/apps/api/src/middleware/auth.ts b/apps/api/src/middleware/auth.ts
index dbdbb1f..1417614 100644
--- a/apps/api/src/middleware/auth.ts
+++ b/apps/api/src/middleware/auth.ts
@@ -1,5 +1,5 @@
 import type { MiddlewareHandler } from "hono";
-import { auth } from "../lib/auth.js";
+import { getAuth } from "../lib/auth.js";
 
 export interface AuthUser {
   id: string;
@@ -37,7 +37,7 @@ export const authMiddleware: MiddlewareHandler = async (c, next) => {
     return;
   }
 
-  const session = await auth.api.getSession({
+  const session = await getAuth().api.getSession({
     headers: c.req.raw.headers,
   });