cachekit-io · 27Bslash6 · Aug 5, 2026 · Aug 4, 2026 · Aug 4, 2026
diff --git a/.secrets.baseline b/.secrets.baseline
@@ -231,7 +231,7 @@
         "filename": "src/cachekit/config/decorator.py",
         "hashed_secret": "1a9a9d37d8305b0cd8353468065cf844259e1b1f",
         "is_verified": false,
-        "line_number": 572
+        "line_number": 567
       }
     ],
     "src/cachekit/serializers/interop_serializer.py": [
@@ -887,5 +887,5 @@
       }
     ]
   },
-  "generated_at": "2026-07-29T00:15:05Z"
+  "generated_at": "2026-08-04T22:16:14Z"
 }
diff --git a/README.md b/README.md
@@ -166,7 +166,6 @@ def get_user_profile(user_id: int):
 | Encryption | - | - | - | - | ✅ Required |
 | L1 SWR (L1-only mode) | - | ✅ | - | ✅ | ✅ |
 | L1 Invalidation | - | - | - | ✅ | ✅ |
-| L1 Namespace Index | - | - | - | ✅ | ✅ |
 | Prometheus Metrics | - | - | - | ✅ | ✅ |
 | Tracing | - | ✅ | - | ✅ | ✅ |
 | Structured Logging | - | ✅ | - | ✅ | ✅ |

diff --git a/docs/configuration.md b/docs/configuration.md
@@ -245,7 +245,6 @@ from cachekit.config import L1CacheConfig
         max_size_mb=100,
         swr_enabled=True,
         swr_threshold_ratio=0.5,  # Refresh at 50% of TTL
-        namespace_index=True,
     ),
     backend=None
 )
@@ -261,12 +260,10 @@ def my_function():
 | `max_size_mb` | int | `100` | Maximum L1 cache size in MB |
 | `swr_enabled` | bool | `True` | Enable stale-while-revalidate (SWR) — [L1-only mode](#l1-only-mode-backendnone) only |
 | `swr_threshold_ratio` | float | `0.5` | Refresh at X% of TTL, in `(0.0, 1.0]` — L1-only mode only |
-| `namespace_index` | bool | `True` | Enable fast namespace-based invalidation |
 
 **L1 Cache Concepts:**
 - **Freshness**: When to serve stale data + trigger background refresh (SWR, [L1-only mode](#l1-only-mode-backendnone) only — with a backend configured these fields have no effect)
 - **Expiry**: Hard deadline when entry is deleted from cache
-- **Namespace**: Logical grouping for bulk invalidation (see [L1 Invalidation Guide](features/l1-invalidation.md))
 
 ### L1-Only Mode (`backend=None`)
 
@@ -343,14 +340,14 @@ def secure_function():
 
 **Feature Matrix by Intent:**
 
-| Intent | SWR | Invalidation | Namespace Index | Max Size | Notes |
-|--------|-----|--------------|-----------------|----------|-------|
-| `minimal()` | ❌ | ❌ | ❌ | 100 MB | Speed-first, no integrity check |
-| `test()` | ❌ | ❌ | ❌ | 100 MB | Deterministic, no monitoring |
-| `dev()` | L1-only¹ | ❌ | ❌ | 100 MB | Verbose logs, no Prometheus |
-| `production()` | L1-only¹ | ✓ | ✓ | 100 MB | Full observability |
-| `secure()` | L1-only¹ | ✓ | ✓ | 100 MB | AES-256-GCM encryption required |
-| `io()` | ✓ | ✓ | ✓ | 100 MB | Managed SaaS backend (closed beta — [request access](https://cachekit.io)); past-TTL [SWR](#stale-while-revalidate-stale_ttl) default-on (`stale_ttl = ttl`) |
+| Intent | SWR | Invalidation | Max Size | Notes |
+|--------|-----|--------------|----------|-------|
+| `minimal()` | ❌ | ❌ | 100 MB | Speed-first, no integrity check |
+| `test()` | ❌ | ❌ | 100 MB | Deterministic, no monitoring |
+| `dev()` | L1-only¹ | ❌ | 100 MB | Verbose logs, no Prometheus |
+| `production()` | L1-only¹ | ✓ | 100 MB | Full observability |
+| `secure()` | L1-only¹ | ✓ | 100 MB | AES-256-GCM encryption required |
+| `io()` | ✓ | ✓ | 100 MB | CachekitIO managed SaaS backend (closed beta — [request access](https://cachekit.io)); past-TTL [SWR](#stale-while-revalidate-stale_ttl) default-on (`stale_ttl = ttl`) |
 
 ¹ Within-TTL refresh-ahead SWR runs **only in L1-only mode** (`backend=None`), where the SDK re-runs your function in the background past `ttl * swr_threshold_ratio`. With a backend configured, these presets have no SWR — `swr_enabled` has no effect outside L1-only mode (Redis exposes no read-side freshness signal). The only backed SWR is `@cache.io`'s past-TTL [`stale_ttl`](#stale-while-revalidate-stale_ttl) mode.
 

diff --git a/docs/features/l1-invalidation.md b/docs/features/l1-invalidation.md
@@ -221,8 +221,6 @@ config = L1CacheConfig(
     # SWR Settings
     swr_enabled=True,                # Enable SWR (default: True)
     swr_threshold_ratio=0.5,         # Refresh at X% of TTL (default: 0.5 = 50%)
-
-    namespace_index=True,            # Enable O(1) namespace lookups (default: True)
 )
 ```
 
@@ -232,7 +230,6 @@ config = L1CacheConfig(
 | `max_size_mb` | int | `100` | Maximum memory usage in MB |
 | `swr_enabled` | bool | `True` | Enable stale-while-revalidate (L1-only mode, requires a `ttl`) |
 | `swr_threshold_ratio` | float | `0.5` | Refresh at X% of TTL, in `(0.0, 1.0]` |
-| `namespace_index` | bool | `True` | Enable fast namespace lookups |
 
 ### Intent Presets
 
@@ -241,7 +238,7 @@ CacheKit includes preconfigured presets for common use cases:
 ```python notest
 from cachekit import cache
 
-# Development: SWR only, no namespace indexing
+# Development: SWR only
 @cache.dev()
 def dev_function():
     pass
@@ -269,14 +266,14 @@ def test_function():
 
 **Feature Behavior by Preset:**
 
-| Preset | SWR | Namespace Index |
-|--------|-----|-----------------|
-| `minimal()` | ❌ | ❌ |
-| `test()` | ❌ | ❌ |
-| `dev()` | L1-only¹ | ❌ |
-| `production()` | L1-only¹ | ✓ |
-| `secure()` | L1-only¹ | ✓ |
-| `io()` | ✓² | ✓ |
+| Preset | SWR |
+|--------|-----|
+| `minimal()` | ❌ |
+| `test()` | ❌ |
+| `dev()` | L1-only¹ |
+| `production()` | L1-only¹ |
+| `secure()` | L1-only¹ |
+| `io()` | ✓² |
 
 ¹ Within-TTL SWR runs only in L1-only mode (`backend=None`) — with a backend configured, `swr_enabled` has no effect (see the callout at the top of this page).
 ² `@cache.io` ships past-TTL SWR via [`stale_ttl`](../configuration.md#stale-while-revalidate-stale_ttl) (default-on), using the CachekitIO backend's freshness signal — a different mechanism from the L1-only within-TTL refresh described here.
@@ -340,7 +337,6 @@ SWR keeps hits at L1 speed, even when serving slightly stale data. In backed mod
 
 ### Memory Impact
 
-- Namespace indexing: ~100 bytes per unique namespace
 - L1-only SWR bookkeeping: a per-entry version counter plus ~8 bytes per key with a refresh in flight
 
 For typical workloads (1000s of keys), overhead is <1MB.

diff --git a/src/cachekit/config/decorator.py b/src/cachekit/config/decorator.py
@@ -337,7 +337,6 @@ def minimal(cls, **kwargs: Any) -> DecoratorConfig:
             l1=L1CacheConfig(
                 enabled=True,
                 swr_enabled=False,
-                namespace_index=False,
             ),
             circuit_breaker=CircuitBreakerConfig(enabled=False),
             backpressure=BackpressureConfig(enabled=True),
@@ -377,7 +376,6 @@ def production(cls, **kwargs: Any) -> DecoratorConfig:
             l1=L1CacheConfig(
                 enabled=True,
                 swr_enabled=True,
-                namespace_index=True,
             ),
             circuit_breaker=CircuitBreakerConfig(enabled=True),
             backpressure=BackpressureConfig(enabled=True),
@@ -442,7 +440,6 @@ def secure(cls, master_key: str, tenant_extractor: Callable[..., str] | None = N
             l1=L1CacheConfig(
                 enabled=True,  # L1 stores encrypted bytes. Enabled: ~50ns hits vs 2-7ms Redis
                 swr_enabled=True,
-                namespace_index=True,
             ),
             encryption=EncryptionConfig(
                 enabled=True,
@@ -490,7 +487,6 @@ def dev(cls, **kwargs: Any) -> DecoratorConfig:
             l1=L1CacheConfig(
                 enabled=True,
                 swr_enabled=True,
-                namespace_index=False,
             ),
             circuit_breaker=CircuitBreakerConfig(enabled=True),
             backpressure=BackpressureConfig(enabled=True),
@@ -530,7 +526,6 @@ def test(cls, **kwargs: Any) -> DecoratorConfig:
             l1=L1CacheConfig(
                 enabled=True,
                 swr_enabled=False,
-                namespace_index=False,
             ),
             circuit_breaker=CircuitBreakerConfig(enabled=False),
             backpressure=BackpressureConfig(enabled=False),
@@ -603,7 +598,6 @@ def io(cls, **kwargs: Any) -> DecoratorConfig:
             l1=L1CacheConfig(
                 enabled=True,
                 swr_enabled=True,
-                namespace_index=True,
             ),
             circuit_breaker=CircuitBreakerConfig(enabled=True),
             backpressure=BackpressureConfig(enabled=True),

diff --git a/src/cachekit/config/nested.py b/src/cachekit/config/nested.py
@@ -30,7 +30,6 @@ class L1CacheConfig:
             task and sync functions via a daemon thread.
         swr_threshold_ratio: Fraction of TTL after which a hit triggers a background
             refresh, in (0.0, 1.0] (default: 0.5)
-        namespace_index: Enable fast namespace-based invalidation (default: True)
 
     Examples:
         Create with defaults:
@@ -58,7 +57,6 @@ class L1CacheConfig:
     max_size_mb: int | None = None
     swr_enabled: bool = True
     swr_threshold_ratio: float = 0.5
-    namespace_index: bool = True
 
     def validate(self) -> None:
         """Validate L1 cache configuration.

diff --git a/src/cachekit/l1_cache.py b/src/cachekit/l1_cache.py
@@ -8,7 +8,7 @@
 import math
 import threading
 import time
-from collections import OrderedDict, defaultdict
+from collections import OrderedDict
 from dataclasses import dataclass
 from typing import Any, Optional
 
@@ -27,7 +27,6 @@ class CacheEntry:
     value: bytes
     expires_at: float
     size_bytes: int
-    namespace: Optional[str] = None
 
     def is_expired(self) -> bool:
         """Check if entry has expired."""
@@ -60,15 +59,13 @@ def __init__(
         max_memory_mb: int = 100,
         ttl_buffer_seconds: float = 1.0,
         namespace: str = "default",
-        config: Optional[Any] = None,
     ):
         """Initialize L1 cache.
 
         Args:
             max_memory_mb: Maximum memory usage in MB (default 100MB)
             ttl_buffer_seconds: Buffer time before Redis TTL expiry (default 1s)
             namespace: Cache namespace for isolation
-            config: Optional L1CacheConfig for invalidation features (namespace index)
         """
         self.max_memory_bytes = max_memory_mb * 1024 * 1024
         self.ttl_buffer_seconds = ttl_buffer_seconds
@@ -88,10 +85,6 @@ def __init__(
         self._evictions = 0
         self._expired_evictions = 0
 
-        # Namespace index for O(1) invalidation (optional)
-        if config and config.namespace_index:
-            self._namespace_index: dict[str, set[str]] = defaultdict(set)
-
         logger.info(
             "L1Cache initialized: namespace=%s, max_memory=%dMB, ttl_buffer=%.1fs",
             namespace,
@@ -151,7 +144,6 @@ def put(
         value: bytes,
         redis_ttl: Optional[float] = None,
         expires_at: Optional[float] = None,
-        namespace: Optional[str] = None,
     ) -> None:
         """Store value in L1 cache with TTL.
 
@@ -160,7 +152,6 @@ def put(
             value: Bytes to cache (encrypted or plaintext msgpack, not deserialized object)
             redis_ttl: TTL in seconds from Redis (used to calculate expiry)
             expires_at: Absolute expiry timestamp (overrides redis_ttl)
-            namespace: Optional namespace for invalidation support
 
         Raises:
             TypeError: if `value` is not exactly `bytes`. L1 stores raw bytes only; a memoryview
@@ -219,22 +210,15 @@ def put(
             if key in self._cache:
                 old_entry = self._cache[key]
                 self._current_memory_bytes -= old_entry.size_bytes
-                # Remove old namespace index entry
-                if hasattr(self, "_namespace_index") and old_entry.namespace:
-                    self._namespace_index[old_entry.namespace].discard(key)
 
             # Evict entries if needed to make room
             self._evict_for_space(size)
 
             # Store new entry
-            entry = CacheEntry(value=value, expires_at=expiry, size_bytes=size, namespace=namespace)
+            entry = CacheEntry(value=value, expires_at=expiry, size_bytes=size)
             self._cache[key] = entry
             self._current_memory_bytes += size
 
-            # Update namespace index
-            if hasattr(self, "_namespace_index") and namespace:
-                self._namespace_index[namespace].add(key)
-
             # Move to end (most recently used)
             self._cache.move_to_end(key)
 
@@ -248,10 +232,6 @@ def _remove_entry(self, key: str) -> None:
             entry = self._cache.pop(key)
             self._current_memory_bytes -= entry.size_bytes
 
-            # Update namespace index
-            if hasattr(self, "_namespace_index") and entry.namespace:
-                self._namespace_index[entry.namespace].discard(key)
-
     def _evict_for_space(self, needed_bytes: int) -> None:
         """Evict LRU entries to make space for new entry.
 
@@ -289,67 +269,6 @@ def invalidate(self, key: str) -> None:
         with self._lock:
             self._remove_entry(key)
 
-    def invalidate_by_key(self, key: str) -> bool:
-        """Invalidate a specific cache key.
-
-        Args:
-            key: Cache key to invalidate
-
-        Returns:
-            True if key was found and removed, False otherwise
-        """
-        with self._lock:
-            if key in self._cache:
-                self._remove_entry(key)
-                return True
-            return False
-
-    def invalidate_by_namespace(self, namespace: str) -> int:
-        """Invalidate all entries in a namespace.
-
-        Args:
-            namespace: Namespace to invalidate
-
-        Returns:
-            Number of entries invalidated
-        """
-        with self._lock:
-            # Use namespace index if available (O(1) lookup + O(k) delete)
-            if hasattr(self, "_namespace_index"):
-                keys_to_remove = list(self._namespace_index.get(namespace, set()))
-                for key in keys_to_remove:
-                    self._remove_entry(key)
-                # Clear namespace index entry
-                if namespace in self._namespace_index:
-                    del self._namespace_index[namespace]
-                return len(keys_to_remove)
-
-            # Fallback: scan all entries (O(n))
-            keys_to_remove = [key for key, entry in self._cache.items() if entry.namespace == namespace]
-            for key in keys_to_remove:
-                self._remove_entry(key)
-            return len(keys_to_remove)
-
-    def invalidate_all(self) -> int:
-        """Invalidate all entries in cache.
-
-        Returns:
-            Number of entries invalidated
-        """
-        with self._lock:
-            count = len(self._cache)
-
-            # Clear all data structures
-            self._cache.clear()
-            self._current_memory_bytes = 0
-
-            # Clear namespace index
-            if hasattr(self, "_namespace_index"):
-                self._namespace_index.clear()
-
-            logger.info("L1Cache invalidated all %d entries for namespace: %s", count, self.namespace)
-            return count
-
     def clear(self) -> None:
         """Clear all entries from L1 cache."""
         with self._lock: