diff --git a/sketch.rs b/sketch.rs
new file mode 100644
index 000000000..e355e1af5
--- /dev/null
+++ b/sketch.rs
@@ -0,0 +1,135 @@
+// crates/orchestrator/src/network/node.rs
+
+impl NetworkNode {
+    /// Tar this node's database into `out_path` (gzip). Archive layout:
+    /// `data/` at the top, plus `relay-data/` for cumulus collators
+    /// (auto-detected from the node's context). Directly consumable by
+    /// `with_db_snapshot` on a sibling node.
+    ///
+    /// The caller is responsible for pausing the node before calling this;
+    /// snapshotting a running node risks a torn RocksDB state.
+    ///
+    /// `kind` controls whether per-node identity (`keystore/`, `network/`)
+    /// is included — see [`SnapshotKind`].
+    pub async fn snapshot_db(
+        &self,
+        out_path: impl AsRef<Path>,
+        kind: SnapshotKind,
+    ) -> Result<NodeSnapshot, anyhow::Error>;
+}
+
+/// Identity-handling policy for [`NetworkNode::snapshot_db`].
+#[derive(Default)]
+pub enum SnapshotKind {
+    /// Strips the node's identity, only DB. Safe to load on any number of sibling
+    /// nodes.
+    #[default]
+    Shareable,
+    /// Includes the node's identity (`keystore/` and `network/`). Use
+    /// only when the snapshot will be loaded back into a node that plays
+    /// the same role as the source. Loading a `Full` snapshot on a
+    /// different node causes equivocation and peer-id collisions.
+    Full,
+}
+
+/// Result of [`NetworkNode::snapshot_db`].
+pub struct NodeSnapshot {
+    /// Absolute path to the produced `.tgz`.
+    pub path: PathBuf,
+    /// Hex-encoded SHA-256 of the archive contents.
+    pub sha256: String,
+    /// Size of the archive in bytes.
+    pub size: u64,
+    /// Name of the node this snapshot was taken from.
+    pub node_name: String,
+}
+
+
+// crates/orchestrator/src/network.rs
+
+impl<FS> Network<FS> {
+    /// Pause every node in the network (SIGSTOP). Issued in parallel.
+    pub async fn pause(&self) -> Result<(), anyhow::Error>;
+
+    /// Resume every node in the network (SIGCONT). Issued in parallel.
+    pub async fn resume(&self) -> Result<(), anyhow::Error>;
+}
+
+
+// crates/sdk/src/snapshot.rs  (new module, re-exported as zombienet_sdk::snapshot)
+
+/// Assembles a single `bundle.tar.gz` from one or more [`NodeSnapshot`]s
+/// plus a JSON `user_data` blob. The bundle is the unit of upload.
+///
+/// Layout inside the bundle:
+/// ```text
+/// <archive1>.tgz
+/// <archive2>.tgz
+/// ...
+/// manifest.json   // schema: SnapshotManifest
+/// ```
+///
+/// Uses a typestate to make [`build`](BundleBuilder::build) unreachable
+/// until at least one archive has been added. Matches the SDK's
+/// `NetworkConfigBuilder<Initial, …>` convention.
+pub struct BundleBuilder<S = Empty> { /* … */ }
+
+/// Typestate marker — no archives added yet.
+pub struct Empty;
+/// Typestate marker — at least one archive has been added.
+pub struct NonEmpty;
+
+impl BundleBuilder<Empty> {
+    pub fn new() -> Self;
+
+    /// Add the first per-node archive. Transitions the builder to the
+    /// [`NonEmpty`] state, which is the only state that exposes
+    /// [`build`](BundleBuilder::build).
+    pub fn add(self, snap: NodeSnapshot) -> BundleBuilder<NonEmpty>;
+}
+
+impl BundleBuilder<NonEmpty> {
+    /// Add a subsequent per-node archive.
+    pub fn add(self, snap: NodeSnapshot) -> Self;
+
+    /// Produce `out_path` (gzipped tarball). Only callable once at least
+    /// one archive has been added — enforced at compile time via the
+    /// [`NonEmpty`] typestate.
+    pub fn build(self, out_path: impl AsRef<Path>) -> Result<Bundle, anyhow::Error>;
+}
+
+impl<S> BundleBuilder<S> {
+    /// Attach an arbitrary serializable blob. Stored as JSON under
+    /// `user_data` in the manifest. Test authors put block heights,
+    /// CIDs, release tags, "number of collators", etc. here. Can be
+    /// called before or after [`add`](BundleBuilder::add); last call wins.
+    pub fn user_data<T: serde::Serialize>(self, data: T) -> Self;
+}
+
+/// Result of [`BundleBuilder::build`].
+pub struct Bundle {
+    pub path: PathBuf,
+    pub sha256: String,
+    pub size: u64,
+}
+
+/// Schema of `manifest.json` inside the bundle. Versioned —
+/// `schema_version` bumps are breaking changes.
+#[derive(serde::Serialize, serde::Deserialize)]
+pub struct SnapshotManifest {
+    pub schema_version: u32,
+    /// RFC 3339 timestamp at bundle-build time.
+    pub created_at: String,
+    pub archives: Vec<ArchiveEntry>,
+    /// Caller-provided payload from [`BundleBuilder::user_data`].
+    pub user_data: serde_json::Value,
+}
+
+#[derive(serde::Serialize, serde::Deserialize)]
+pub struct ArchiveEntry {
+    /// Basename inside the bundle (e.g. `"relaychain-db.tgz"`).
+    pub file: String,
+    pub sha256: String,
+    pub size: u64,
+    pub node_name: String,
+}