diff --git a/apps/mesh/src/settings/resolve-config.ts b/apps/mesh/src/settings/resolve-config.ts
index cbcc023470..e34dffd5b4 100644
--- a/apps/mesh/src/settings/resolve-config.ts
+++ b/apps/mesh/src/settings/resolve-config.ts
@@ -228,6 +228,9 @@ export function resolveConfig(
       envVars.AWS_S3_TENANT_PROVISIONER_ACCESS_KEY_ID,
     awsS3TenantProvisionerSecretAccessKey:
       envVars.AWS_S3_TENANT_PROVISIONER_SECRET_ACCESS_KEY,
+
+    decoCacheS3Bucket: envVars.DECO_CACHE_S3_BUCKET,
+    decoCacheS3Region: envVars.DECO_CACHE_S3_REGION,
   };
 
   return {
diff --git a/apps/mesh/src/settings/types.ts b/apps/mesh/src/settings/types.ts
index d5b0dc03bd..e7f7c0d76b 100644
--- a/apps/mesh/src/settings/types.ts
+++ b/apps/mesh/src/settings/types.ts
@@ -138,6 +138,10 @@ export interface Settings {
   awsS3TenantRoleArn: string | undefined;
   awsS3TenantProvisionerAccessKeyId: string | undefined;
   awsS3TenantProvisionerSecretAccessKey: string | undefined;
+
+  // deco S3 cache — pre-signed URL generation for deco-sites sandbox warm-up.
+  decoCacheS3Bucket: string | undefined;
+  decoCacheS3Region: string | undefined;
 }
 
 export interface CliFlags {
diff --git a/apps/mesh/src/tools/sandbox/start.ts b/apps/mesh/src/tools/sandbox/start.ts
index eb1422e909..eb25c445a1 100644
--- a/apps/mesh/src/tools/sandbox/start.ts
+++ b/apps/mesh/src/tools/sandbox/start.ts
@@ -8,6 +8,9 @@
  * (user, branch) key — no stale-sandbox teardown is needed on kind change.
  */
 
+import { GetObjectCommand, S3Client } from "@aws-sdk/client-s3";
+import { AssumeRoleCommand, STSClient } from "@aws-sdk/client-sts";
+import { getSignedUrl } from "@aws-sdk/s3-request-presigner";
 import { z } from "zod";
 import type { SandboxRecord } from "@decocms/mesh-sdk";
 import {
@@ -66,6 +69,53 @@ const sandboxProviderKindInputSchema = z.enum([
   "cluster",
 ]);
 
+async function tryGenerateDecoCachePresignedUrl(
+  owner: string,
+  repo: string,
+): Promise<string | undefined> {
+  if (owner !== "deco-sites") return undefined;
+  const settings = getSettings();
+  const bucket = settings.decoCacheS3Bucket;
+  const region = settings.decoCacheS3Region;
+  const roleArn = settings.awsS3TenantRoleArn;
+  if (!bucket || !region || !roleArn) return undefined;
+  try {
+    const accessKeyId = settings.awsS3TenantProvisionerAccessKeyId;
+    const secretAccessKey = settings.awsS3TenantProvisionerSecretAccessKey;
+    const sts = new STSClient({
+      region,
+      ...(accessKeyId && secretAccessKey
+        ? { credentials: { accessKeyId, secretAccessKey } }
+        : {}),
+    });
+    const { Credentials: creds } = await sts.send(
+      new AssumeRoleCommand({
+        RoleArn: roleArn,
+        RoleSessionName: "deco-cache-presign",
+      }),
+    );
+    if (!creds?.AccessKeyId || !creds.SecretAccessKey) return undefined;
+    const s3 = new S3Client({
+      region,
+      credentials: {
+        accessKeyId: creds.AccessKeyId,
+        secretAccessKey: creds.SecretAccessKey,
+        sessionToken: creds.SessionToken,
+      },
+    });
+    return await getSignedUrl(
+      s3,
+      new GetObjectCommand({
+        Bucket: bucket,
+        Key: `${owner}/${repo}/cache.tar.zst`,
+      }),
+      { expiresIn: 900 },
+    );
+  } catch {
+    return undefined;
+  }
+}
+
 export const SANDBOX_START = defineTool({
   name: "SANDBOX_START",
   description: "Start a sandbox with the connected GitHub repo and dev server.",
@@ -297,6 +347,9 @@ async function provisionSandbox(
         userEmail: string;
         branch: string;
         displayName: string;
+        owner?: string;
+        name?: string;
+        denoCachePresignedUrl?: string;
       }
     | undefined;
 
@@ -376,6 +429,12 @@ async function provisionSandbox(
       userEmail: gitUserEmail,
       branch,
       displayName: `${githubRepo.owner}/${githubRepo.name}`,
+      owner: githubRepo.owner,
+      name: githubRepo.name,
+      denoCachePresignedUrl: await tryGenerateDecoCachePresignedUrl(
+        githubRepo.owner,
+        githubRepo.name,
+      ),
     };
   }
 
diff --git a/bun.lock b/bun.lock
index d8105075e5..d651b11a99 100644
--- a/bun.lock
+++ b/bun.lock
@@ -38,7 +38,7 @@
     },
     "apps/mesh": {
       "name": "decocms",
-      "version": "3.53.0",
+      "version": "3.57.0",
       "bin": {
         "deco": "./dist/server/cli.js",
       },
@@ -211,7 +211,7 @@
     },
     "packages/e2e": {
       "name": "@decocms/e2e",
-      "version": "0.0.1",
+      "version": "0.0.2",
       "dependencies": {
         "@decocms/harness": "workspace:*",
         "@decocms/sandbox": "workspace:*",
@@ -311,8 +311,9 @@
     },
     "packages/sandbox": {
       "name": "@decocms/sandbox",
-      "version": "1.3.1",
+      "version": "1.3.2",
       "dependencies": {
+        "@aws-sdk/client-s3": "^3.1013.0",
         "@decocms/harness": "workspace:*",
         "@decocms/std": "workspace:*",
         "@kubernetes/client-node": "^1.4.0",
diff --git a/deploy/helm/sandbox-env/templates/_helpers.tpl b/deploy/helm/sandbox-env/templates/_helpers.tpl
index f2a3ab7c61..42ca0cab31 100644
--- a/deploy/helm/sandbox-env/templates/_helpers.tpl
+++ b/deploy/helm/sandbox-env/templates/_helpers.tpl
@@ -146,6 +146,7 @@ atomic and gives a pointer to the right install command.
 {{- end }}
 {{- end }}
 
+
 {{- define "sandbox-env.housekeeperName" -}}
 {{- printf "sandbox-housekeeper-%s" (include "sandbox-env.envName" .) -}}
 {{- end }}
diff --git a/packages/sandbox/daemon/setup/install.ts b/packages/sandbox/daemon/setup/install.ts
index ae07e63627..9443bbee6a 100644
--- a/packages/sandbox/daemon/setup/install.ts
+++ b/packages/sandbox/daemon/setup/install.ts
@@ -1,10 +1,70 @@
 import { existsSync } from "node:fs";
+import { createWriteStream } from "node:fs";
+import { mkdtemp, rm } from "node:fs/promises";
+import { homedir, tmpdir } from "node:os";
 import { join } from "node:path";
+import { pipeline } from "node:stream/promises";
 import { PACKAGE_MANAGER_DAEMON_CONFIG } from "../constants";
 import { resolvePmRoot } from "../paths";
 import type { Config } from "../types";
 import { spawnSetupStep } from "./spawn-step";
 
+/**
+ * For Deno projects, tries to pre-populate $DENO_DIR from a pre-signed S3 URL
+ * provided by mesh. The URL is scoped to exactly one object (owner/repo/cache.tar.zst)
+ * and expires in 15 minutes — no AWS credentials needed in the sandbox pod.
+ *
+ * Non-fatal: any failure (URL expired, object not found, network error) is logged
+ * and the sandbox continues to start normally.
+ */
+export function tryWarmDenoCache(deps: InstallDeps): Promise<void> | null {
+  const { config } = deps;
+  if (config.application?.packageManager?.name !== "deno") return null;
+
+  const presignedUrl = config.denoCache?.presignedUrl;
+  if (!presignedUrl) return null;
+
+  return (async () => {
+    deps.onChunk(
+      "setup",
+      "\r\n[deno cache] fetching from pre-signed URL...\r\n",
+    );
+
+    let tmpDir: string | null = null;
+    try {
+      const res = await fetch(presignedUrl);
+      if (!res.ok) throw new Error(`HTTP ${res.status}`);
+      if (!res.body) throw new Error("empty response body");
+
+      tmpDir = await mkdtemp(join(tmpdir(), "deco-cache-"));
+      const tmpFile = join(tmpDir, "cache.tar.zst");
+      const ws = createWriteStream(tmpFile);
+      await pipeline(res.body as unknown as NodeJS.ReadableStream, ws);
+
+      const denoDir =
+        deps.env?.DENO_DIR ?? process.env.DENO_DIR ?? join(homedir(), ".deno");
+      const cmd = [
+        `mkdir -p "${denoDir}"`,
+        `zstd -d "${tmpFile}" --stdout | tar xf - -C "${denoDir}" --no-same-permissions --no-same-owner`,
+        `echo "[deno cache] restored from S3"`,
+      ].join(" && ");
+
+      await spawnSetupStep(cmd, deps.onChunk, {
+        dropPrivileges: deps.dropPrivileges,
+        env: deps.env,
+      });
+    } catch {
+      deps.onChunk(
+        "setup",
+        "[deno cache] not available — deno will fetch deps on first run\r\n",
+      );
+    } finally {
+      if (tmpDir)
+        await rm(tmpDir, { recursive: true, force: true }).catch(() => {});
+    }
+  })();
+}
+
 export interface InstallDeps {
   config: Config;
   dropPrivileges?: boolean;
diff --git a/packages/sandbox/daemon/setup/orchestrator.ts b/packages/sandbox/daemon/setup/orchestrator.ts
index 6795282088..ba79d5ad20 100644
--- a/packages/sandbox/daemon/setup/orchestrator.ts
+++ b/packages/sandbox/daemon/setup/orchestrator.ts
@@ -27,7 +27,7 @@ import type { Application, Config } from "../types";
 import { autodetectApplication } from "./autodetect";
 import { spawnClone } from "./clone";
 import { configureGitIdentity } from "./identity";
-import { spawnInstall } from "./install";
+import { spawnInstall, tryWarmDenoCache } from "./install";
 import { spawnSetupStep } from "./spawn-step";
 import { installProtectedBranchHook } from "../git/protect-branch";
 
@@ -323,6 +323,17 @@ export class SetupOrchestrator {
     // present yet). Treat as success so the caller proceeds to start; mark
     // the install fingerprint so resume doesn't retry on every boot.
     if (!installPromise) {
+      // For deno, opportunistically pre-populate the cache from S3.
+      // Non-fatal: failure just means a cold first run.
+      const cachePromise = tryWarmDenoCache({
+        config,
+        env: config.env,
+        onChunk: (_src, data) => {
+          this.rawChunk(data);
+          installTee.write(data);
+        },
+      });
+      if (cachePromise) await cachePromise;
       installTee.close();
       this.markInstallSucceeded(config);
       return true;
diff --git a/packages/sandbox/daemon/types.ts b/packages/sandbox/daemon/types.ts
index e40c320792..0890742002 100644
--- a/packages/sandbox/daemon/types.ts
+++ b/packages/sandbox/daemon/types.ts
@@ -36,6 +36,10 @@ export interface GitRepository {
   readonly cloneUrl: string;
   readonly branch?: string;
   readonly repoName?: string;
+  /** GitHub org or user that owns the repo (e.g. "deco-sites"). */
+  readonly owner?: string;
+  /** Repository name without owner (e.g. "my-site"). */
+  readonly name?: string;
 }
 
 export interface GitConfig {
@@ -67,6 +71,7 @@ export interface TenantConfig {
   readonly operator?: OperatorIdentity;
   readonly application?: Application;
   readonly env?: Readonly<Record<string, string>>;
+  readonly denoCache?: { readonly presignedUrl: string };
 }
 
 /** In-memory enriched view: TenantConfig + derivations. */
diff --git a/packages/sandbox/image/Dockerfile b/packages/sandbox/image/Dockerfile
index 1a0de19c34..af50f90126 100644
--- a/packages/sandbox/image/Dockerfile
+++ b/packages/sandbox/image/Dockerfile
@@ -9,7 +9,7 @@ ARG DENO_VERSION=v1.46.3
 RUN apt-get update \
   && apt-get install -y --no-install-recommends \
        bash ca-certificates curl git gnupg locales python3 python3-pip \
-       ripgrep unzip \
+       ripgrep unzip zstd \
   && sed -i 's/^#\s*en_US.UTF-8 UTF-8/en_US.UTF-8 UTF-8/' /etc/locale.gen \
   && locale-gen \
   && curl -fsSL https://deb.nodesource.com/setup_${NODE_MAJOR}.x | bash - \
diff --git a/packages/sandbox/server/provider/agent-sandbox/runner.ts b/packages/sandbox/server/provider/agent-sandbox/runner.ts
index 94eaa54f44..30d08b8d78 100644
--- a/packages/sandbox/server/provider/agent-sandbox/runner.ts
+++ b/packages/sandbox/server/provider/agent-sandbox/runner.ts
@@ -1324,6 +1324,7 @@ export class AgentSandboxProvider implements SandboxProvider {
       repo: opts?.repo ?? null,
       port: opts?.workload?.devPort ?? DEFAULT_DEV_PORT,
       tenant: opts?.tenant ?? undefined,
+      denoCachePresignedUrl: opts?.repo?.denoCachePresignedUrl,
     });
   }
 
diff --git a/packages/sandbox/server/provider/shared/build-config-payload.ts b/packages/sandbox/server/provider/shared/build-config-payload.ts
index bf0428ad61..05b7b2e78c 100644
--- a/packages/sandbox/server/provider/shared/build-config-payload.ts
+++ b/packages/sandbox/server/provider/shared/build-config-payload.ts
@@ -13,6 +13,7 @@ export function buildConfigPayload(args: {
   port?: number;
   repo: NonNullable<EnsureOptions["repo"]> | null;
   tenant?: EnsureOptions["tenant"];
+  denoCachePresignedUrl?: string;
 }): Partial<TenantConfig> | null {
   const repo = args.repo;
   const git = repo
@@ -21,6 +22,8 @@ export function buildConfigPayload(args: {
           cloneUrl: repo.cloneUrl,
           repoName: repo.displayName ?? deriveRepoLabel(repo.cloneUrl),
           ...(repo.branch ? { branch: repo.branch } : {}),
+          ...(repo.owner ? { owner: repo.owner } : {}),
+          ...(repo.name ? { name: repo.name } : {}),
         },
         identity: {
           userName: repo.userName,
@@ -51,11 +54,16 @@ export function buildConfigPayload(args: {
       }
     : undefined;
 
-  if (!git && !application && !operator) return null;
+  const denoCache = args.denoCachePresignedUrl
+    ? { presignedUrl: args.denoCachePresignedUrl }
+    : undefined;
+
+  if (!git && !application && !operator && !denoCache) return null;
   return {
     ...(git ? { git } : {}),
     ...(operator ? { operator } : {}),
     ...(application ? { application } : {}),
+    ...(denoCache ? { denoCache } : {}),
   };
 }
 
diff --git a/packages/sandbox/server/provider/types.ts b/packages/sandbox/server/provider/types.ts
index 23afd11b77..e6e8b0b36f 100644
--- a/packages/sandbox/server/provider/types.ts
+++ b/packages/sandbox/server/provider/types.ts
@@ -70,6 +70,12 @@ export interface EnsureOptions {
     branch?: string;
     /** Human-readable label for logs/UI; no functional effect. */
     displayName?: string;
+    /** GitHub org or user that owns the repo (e.g. "deco-sites"). */
+    owner?: string;
+    /** Pre-signed URL to download the Deno module cache from S3. */
+    denoCachePresignedUrl?: string;
+    /** Repository name without owner (e.g. "my-site"). */
+    name?: string;
   };
   /** Image override. Non-image runners MUST ignore. */
   image?: string;