diff --git a/Cargo.lock b/Cargo.lock
index a989bc5..7bd9faa 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5,7 +5,7 @@ version = 4
 [[package]]
 name = "corvid-db"
 version = "0.3.2"
-source = "git+https://github.com/corvid-db/corvid.git?tag=v0.3.3#b726ac5a1ebace9f94dc12007a4e06927241cf4c"
+source = "git+https://github.com/corvid-db/corvid.git?tag=v0.3.4#b726ac5a1ebace9f94dc12007a4e06927241cf4c"
 dependencies = [
  "redb",
  "thiserror",
diff --git a/Cargo.toml b/Cargo.toml
index f9d43d2..890991f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -23,7 +23,7 @@ pyo3 = { version = "0.29", features = ["abi3-py311"] }
 # binding pins exact engine tags; the engine PACKAGE is corvid-db —
 # bare `corvid` is an unrelated crates.io crate — its LIB ident is
 # corvid, so `use corvid::…` is unchanged).
-corvid-db = { git = "https://github.com/corvid-db/corvid.git", tag = "v0.3.3" }
+corvid-db = { git = "https://github.com/corvid-db/corvid.git", tag = "v0.3.4" }
 
 [dev-dependencies]
 # Test-only: the variant-inventory snapshot test (src/error.rs)
diff --git a/docs/PLAN.md b/docs/PLAN.md
index 535aa7d..8e2aad2 100644
--- a/docs/PLAN.md
+++ b/docs/PLAN.md
@@ -18,7 +18,7 @@ variants are additive later, decided by the FFI bench).
 | --- | --- |
 | The pyo3 crate (engine-binding layer AND idiom layer — see §3) | `src/*.rs` — `DbPy`/`CollectionPy`/`QueryPy`, value mapping, error mapping, predicates |
 | The public package | `python/corvid/__init__.py` re-exports `corvid._native`; `__init__.pyi` + `py.typed` carry the full typing |
-| The golden-suite port | `tests/test_golden.py` driving `tests/golden/*.txt` (vendored byte-identical from the v0.3.3 release — the pinned engine tag; the same fixtures the C smoke suite and corvid-node run) |
+| The golden-suite port | `tests/test_golden.py` driving `tests/golden/*.txt` (vendored byte-identical from the v0.3.4 release — the pinned engine tag; the same fixtures the C smoke suite and corvid-node run) |
 | Packaging | `pyproject.toml` (maturin, one cp311-abi3 wheel per platform), README (install-pending note), LICENSE (MIT), `.gitignore` |
 | CI | `.github/workflows/ci.yml` — surface gate + lint + golden suite × 4 platform legs (linux-x64/arm64, macos-arm64, windows-x64) × {3.14, 3.13, 3.12, 3.11} + `maturin build` smoke |
 
@@ -35,7 +35,7 @@ totals test pre-scans all files for exactly 267).
 Two architectures were on the table:
 
 1. **(chosen)** A Rust pyo3 crate that links the engine crate directly
-   (`corvid-db = { git = "https://github.com/corvid-db/corvid.git", tag = "v0.3.3" }`
+   (`corvid-db = { git = "https://github.com/corvid-db/corvid.git", tag = "v0.3.4" }`
    — the engine package is `corvid-db` with lib ident `corvid`; bare
    `corvid` on crates.io is an unrelated crate) and exposes the OOP
    surface through native pyo3 classes, built into a Python extension
@@ -222,4 +222,4 @@ Documented corners:
 | Variadic `and_`/`or_` (trailing underscores) | Python keywords; mirrors the JS binding's variadic `and`/`or` |
 | Counter + Arc exclusivity for `compact` | mirrors the ABI §4.13 gate exactly; pinned by admin.txt |
 | pyo3 0.29, maturin 1.x | current crates.io stable lines |
-| Vendored golden fixtures (byte-identical to the v0.3.3 tag — the pinned engine version) | stable text; the suite must run offline and per-PR (verified identical to `crates/corvid-ffi/golden/`) |
+| Vendored golden fixtures (byte-identical to the v0.3.4 tag — the pinned engine version) | stable text; the suite must run offline and per-PR (verified identical to `crates/corvid-ffi/golden/`) |
diff --git a/docs/SURFACE.tsv b/docs/SURFACE.tsv
index 0929906..d6e2f06 100644
--- a/docs/SURFACE.tsv
+++ b/docs/SURFACE.tsv
@@ -122,8 +122,10 @@ corvid::QueryBuilder::run	SELECT shaping	MAPPED	Query.run	golden:queries.txt:QVE
 corvid::Db	Lifecycle	MAPPED	Db	golden:admin.txt:FILEDB
 corvid::Db::open	Lifecycle	MAPPED	Db.open/open_memory/collection/collections/backup/compact	golden:admin.txt (COLLECTIONS/BACKUP/COMPACT)
 corvid::Db::open_in_memory	Lifecycle	MAPPED	Db.open/open_memory/collection/collections/backup/compact	golden:admin.txt (COLLECTIONS/BACKUP/COMPACT)
+corvid::Db::open_with_backend	Lifecycle	N/A	N/A	wasm-only backend seam (redb StorageBackend over custom storage): no C-ABI/native equivalent; browser-binding machinery, not constructible here
 corvid::Db::collection	Lifecycle	MAPPED	Db.open/open_memory/collection/collections/backup/compact	golden:admin.txt (COLLECTIONS/BACKUP/COMPACT)
 corvid::Db::backup	Lifecycle	MAPPED	Db.open/open_memory/collection/collections/backup/compact	golden:admin.txt (COLLECTIONS/BACKUP/COMPACT)
+corvid::Db::backup_with_backend	Lifecycle	N/A	N/A	wasm-only backend seam (redb StorageBackend over custom storage): no C-ABI/native equivalent; browser-binding machinery, not constructible here
 corvid::Db::bulk	Lifecycle	N/A	N/A	put_many covers the bulk fast path (FFI.md §9); Db::bulk not exposed
 corvid::Db::compact	Lifecycle	MAPPED	Db.open/open_memory/collection/collections/backup/compact	golden:admin.txt (COLLECTIONS/BACKUP/COMPACT)
 corvid::Db::collections	Lifecycle	MAPPED	Db.open/open_memory/collection/collections/backup/compact	golden:admin.txt (COLLECTIONS/BACKUP/COMPACT)
@@ -148,12 +150,14 @@ corvid::db::Page	SELECT shaping	MAPPED	Collection.page / Page	golden:mutations.t
 corvid::Store	Lifecycle	N/A	N/A	engine low-level byte KV (Store/WriteBatch/ReadBatch); the v1 binding is typed-document only (FFI.md ruling 1)
 corvid::Store::open	Lifecycle	N/A	N/A	engine low-level byte KV (Store/WriteBatch/ReadBatch); the v1 binding is typed-document only (FFI.md ruling 1)
 corvid::Store::open_in_memory	Lifecycle	N/A	N/A	engine low-level byte KV (Store/WriteBatch/ReadBatch); the v1 binding is typed-document only (FFI.md ruling 1)
+corvid::Store::open_with_backend	Lifecycle	N/A	N/A	wasm-only backend seam (redb StorageBackend over custom storage): no C-ABI/native equivalent; browser-binding machinery, not constructible here
 corvid::Store::set_relaxed_durability	Lifecycle	N/A	N/A	engine low-level byte KV (Store/WriteBatch/ReadBatch); the v1 binding is typed-document only (FFI.md ruling 1)
 corvid::Store::begin_bulk	Lifecycle	N/A	N/A	engine low-level byte KV (Store/WriteBatch/ReadBatch); the v1 binding is typed-document only (FFI.md ruling 1)
 corvid::Store::flush	Lifecycle	N/A	N/A	engine low-level byte KV (Store/WriteBatch/ReadBatch); the v1 binding is typed-document only (FFI.md ruling 1)
 corvid::Store::compact	Lifecycle	N/A	N/A	engine low-level byte KV (Store/WriteBatch/ReadBatch); the v1 binding is typed-document only (FFI.md ruling 1)
 corvid::Store::next_auto_id	Lifecycle	N/A	N/A	engine low-level byte KV (Store/WriteBatch/ReadBatch); the v1 binding is typed-document only (FFI.md ruling 1)
 corvid::Store::backup	Lifecycle	N/A	N/A	engine low-level byte KV (Store/WriteBatch/ReadBatch); the v1 binding is typed-document only (FFI.md ruling 1)
+corvid::Store::backup_with_backend	Lifecycle	N/A	N/A	wasm-only backend seam (redb StorageBackend over custom storage): no C-ABI/native equivalent; browser-binding machinery, not constructible here
 corvid::Store::transaction	Lifecycle	N/A	N/A	engine low-level byte KV (Store/WriteBatch/ReadBatch); the v1 binding is typed-document only (FFI.md ruling 1)
 corvid::Store::read	Lifecycle	N/A	N/A	engine low-level byte KV (Store/WriteBatch/ReadBatch); the v1 binding is typed-document only (FFI.md ruling 1)
 corvid::Store::put	Lifecycle	N/A	N/A	engine low-level byte KV (Store/WriteBatch/ReadBatch); the v1 binding is typed-document only (FFI.md ruling 1)
diff --git a/pyproject.toml b/pyproject.toml
index e9020a3..a7ad235 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -4,7 +4,7 @@ build-backend = "maturin"
 
 [project]
 name = "corvid-python"
-version = "0.3.3"
+version = "0.3.4"
 description = "Python binding for the corvid embedded database — the engine compiled in via pyo3, exposed as idiomatic OOP"
 readme = "README.md"
 license = "MIT"
diff --git a/scripts/surface-gate.sh b/scripts/surface-gate.sh
index 2e277b4..55a0cdc 100755
--- a/scripts/surface-gate.sh
+++ b/scripts/surface-gate.sh
@@ -34,7 +34,7 @@ SURFACE="$ROOT/docs/SURFACE.tsv"
 ENGINE_REPO="corvid-db/corvid"
 
 # The committed N/A baseline for THIS binding (see (c) above).
-NA_BASELINE=155
+NA_BASELINE=159
 
 # ---- locate the engine pin ------------------------------------------------
 pin=""