diff --git a/packages/service-core/src/storage/BucketStorage.ts b/packages/service-core/src/storage/BucketStorage.ts
index 84165fb7c..61b376be0 100644
--- a/packages/service-core/src/storage/BucketStorage.ts
+++ b/packages/service-core/src/storage/BucketStorage.ts
@@ -90,6 +90,11 @@ export interface BucketStorageFactory
    */
   getActiveCheckpoint(): Promise<ActiveCheckpoint>;
 
+  /**
+   * Yields the latest sync checkpoint.
+   */
+  watchActiveCheckpoint(signal: AbortSignal): AsyncIterable<ActiveCheckpoint>;
+
   /**
    * Yields the latest user write checkpoint whenever the sync checkpoint updates.
    */
@@ -118,6 +123,8 @@ export interface ActiveCheckpoint {
   hasSyncRules(): boolean;
 
   getBucketStorage(): Promise<SyncRulesBucketStorage | null>;
+
+  syncRules: PersistedSyncRulesContent | null;
 }
 
 export interface StorageMetrics {
diff --git a/packages/service-core/src/storage/MongoBucketStorage.ts b/packages/service-core/src/storage/MongoBucketStorage.ts
index 9da62758c..46fd1e66b 100644
--- a/packages/service-core/src/storage/MongoBucketStorage.ts
+++ b/packages/service-core/src/storage/MongoBucketStorage.ts
@@ -78,6 +78,9 @@ export class MongoBucketStorage
     db: PowerSyncMongo,
     options: {
       slot_name_prefix: string;
+      /**
+       * Initial Write Checkpoint Mode
+       */
       write_checkpoint_mode?: WriteCheckpointMode;
     }
   ) {
@@ -93,6 +96,10 @@ export class MongoBucketStorage
     });
   }
 
+  get writeCheckpointMode() {
+    return this.writeCheckpointAPI.writeCheckpointMode;
+  }
+
   getInstance(options: PersistedSyncRulesContent): MongoSyncBucketStorage {
     let { id, slot_name } = options;
     if ((typeof id as any) == 'bigint') {
@@ -303,6 +310,10 @@ export class MongoBucketStorage
     return this.writeCheckpointAPI.batchCreateCustomWriteCheckpoints(checkpoints);
   }
 
+  setWriteCheckpointMode(mode: WriteCheckpointMode): void {
+    return this.writeCheckpointAPI.setWriteCheckpointMode(mode);
+  }
+
   async createCustomWriteCheckpoint(options: CustomWriteCheckpointOptions): Promise<bigint> {
     return this.writeCheckpointAPI.createCustomWriteCheckpoint(options);
   }
@@ -425,14 +436,15 @@ export class MongoBucketStorage
           return null;
         }
         return (await this.storageCache.fetch(doc._id)) ?? null;
-      }
-    };
+      },
+      syncRules: doc ? new MongoPersistedSyncRulesContent(this.db, doc) : null
+    } satisfies ActiveCheckpoint;
   }
 
   /**
    * Instance-wide watch on the latest available checkpoint (op_id + lsn).
    */
-  private async *watchActiveCheckpoint(signal: AbortSignal): AsyncIterable<ActiveCheckpoint> {
+  private async *_watchActiveCheckpoint(signal: AbortSignal): AsyncIterable<ActiveCheckpoint> {
     const pipeline: mongo.Document[] = [
       {
         $match: {
@@ -445,7 +457,8 @@ export class MongoBucketStorage
           operationType: 1,
           'fullDocument._id': 1,
           'fullDocument.last_checkpoint': 1,
-          'fullDocument.last_checkpoint_lsn': 1
+          'fullDocument.last_checkpoint_lsn': 1,
+          'fullDocument.content': 1
         }
       }
     ];
@@ -467,7 +480,8 @@ export class MongoBucketStorage
           projection: {
             _id: 1,
             last_checkpoint: 1,
-            last_checkpoint_lsn: 1
+            last_checkpoint_lsn: 1,
+            content: 1
           }
         }
       );
@@ -516,6 +530,7 @@ export class MongoBucketStorage
       if (doc == null) {
         continue;
       }
+
       const op = this.makeActiveCheckpoint(doc);
       // Check for LSN / checkpoint changes - ignore other metadata changes
       if (lastOp == null || op.lsn != lastOp.lsn || op.checkpoint != lastOp.checkpoint) {
@@ -527,9 +542,16 @@ export class MongoBucketStorage
 
   // Nothing is done here until a subscriber starts to iterate
   private readonly sharedIter = new sync.BroadcastIterable((signal) => {
-    return this.watchActiveCheckpoint(signal);
+    return this._watchActiveCheckpoint(signal);
   });
 
+  /**
+   * Watch changes to the active sync rules and checkpoint.
+   */
+  watchActiveCheckpoint(signal: AbortSignal): AsyncIterable<ActiveCheckpoint> {
+    return wrapWithAbort(this.sharedIter, signal);
+  }
+
   /**
    * User-specific watch on the latest checkpoint and/or write checkpoint.
    */
diff --git a/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts b/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts
index 230db3153..aa66b6f28 100644
--- a/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts
+++ b/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts
@@ -17,11 +17,19 @@ export type MongoCheckpointAPIOptions = {
 
 export class MongoWriteCheckpointAPI implements WriteCheckpointAPI {
   readonly db: PowerSyncMongo;
-  readonly mode: WriteCheckpointMode;
+  private _mode: WriteCheckpointMode;
 
   constructor(options: MongoCheckpointAPIOptions) {
     this.db = options.db;
-    this.mode = options.mode;
+    this._mode = options.mode;
+  }
+
+  get writeCheckpointMode() {
+    return this._mode;
+  }
+
+  setWriteCheckpointMode(mode: WriteCheckpointMode): void {
+    this._mode = mode;
   }
 
   async batchCreateCustomWriteCheckpoints(checkpoints: CustomWriteCheckpointOptions[]): Promise<void> {
@@ -29,12 +37,11 @@ export class MongoWriteCheckpointAPI implements WriteCheckpointAPI {
   }
 
   async createCustomWriteCheckpoint(options: CustomWriteCheckpointOptions): Promise<bigint> {
-    if (this.mode !== WriteCheckpointMode.CUSTOM) {
-      throw new framework.errors.ValidationError(
-        `Creating a custom Write Checkpoint when the current Write Checkpoint mode is set to "${this.mode}"`
-      );
-    }
-
+    /**
+     * Allow creating custom checkpoints even if the current mode is not `custom`.
+     * There might be a state where the next sync rules rely on replicating custom
+     * write checkpoints, but the current active sync rules uses managed checkpoints.
+     */
     const { checkpoint, user_id, sync_rules_id } = options;
     const doc = await this.db.custom_write_checkpoints.findOneAndUpdate(
       {
@@ -52,9 +59,9 @@ export class MongoWriteCheckpointAPI implements WriteCheckpointAPI {
   }
 
   async createManagedWriteCheckpoint(checkpoint: ManagedWriteCheckpointOptions): Promise<bigint> {
-    if (this.mode !== WriteCheckpointMode.MANAGED) {
+    if (this.writeCheckpointMode !== WriteCheckpointMode.MANAGED) {
       throw new framework.errors.ValidationError(
-        `Creating a managed Write Checkpoint when the current Write Checkpoint mode is set to "${this.mode}"`
+        `Attempting to create a managed Write Checkpoint when the current Write Checkpoint mode is set to "${this.writeCheckpointMode}"`
       );
     }
 
@@ -77,7 +84,7 @@ export class MongoWriteCheckpointAPI implements WriteCheckpointAPI {
   }
 
   async lastWriteCheckpoint(filters: LastWriteCheckpointFilters): Promise<bigint | null> {
-    switch (this.mode) {
+    switch (this.writeCheckpointMode) {
       case WriteCheckpointMode.CUSTOM:
         if (false == 'sync_rules_id' in filters) {
           throw new framework.errors.ValidationError(`Sync rules ID is required for custom Write Checkpoint filtering`);
diff --git a/packages/service-core/src/storage/write-checkpoint.ts b/packages/service-core/src/storage/write-checkpoint.ts
index 0b61fe0c1..3a9abd216 100644
--- a/packages/service-core/src/storage/write-checkpoint.ts
+++ b/packages/service-core/src/storage/write-checkpoint.ts
@@ -55,6 +55,10 @@ export type ManagedWriteCheckpointOptions = ManagedWriteCheckpointFilters;
 export type LastWriteCheckpointFilters = CustomWriteCheckpointFilters | ManagedWriteCheckpointFilters;
 
 export interface WriteCheckpointAPI {
+  readonly writeCheckpointMode: WriteCheckpointMode;
+
+  setWriteCheckpointMode(mode: WriteCheckpointMode): void;
+
   batchCreateCustomWriteCheckpoints(checkpoints: CustomWriteCheckpointOptions[]): Promise<void>;
 
   createCustomWriteCheckpoint(checkpoint: CustomWriteCheckpointOptions): Promise<bigint>;
diff --git a/packages/service-core/src/util/config/compound-config-collector.ts b/packages/service-core/src/util/config/compound-config-collector.ts
index 78e8500cb..7c2b70c87 100644
--- a/packages/service-core/src/util/config/compound-config-collector.ts
+++ b/packages/service-core/src/util/config/compound-config-collector.ts
@@ -122,7 +122,8 @@ export class CompoundConfigCollector {
       },
       // TODO maybe move this out of the connection or something
       // slot_name_prefix: connections[0]?.slot_name_prefix ?? 'powersync_'
-      slot_name_prefix: 'powersync_'
+      slot_name_prefix: 'powersync_',
+      parameters: baseConfig.parameters ?? {}
     };
 
     return config;
diff --git a/packages/service-core/src/util/config/types.ts b/packages/service-core/src/util/config/types.ts
index e5f461e49..99829526d 100644
--- a/packages/service-core/src/util/config/types.ts
+++ b/packages/service-core/src/util/config/types.ts
@@ -64,4 +64,5 @@ export type ResolvedPowerSyncConfig = {
 
   /** Prefix for postgres replication slot names. May eventually be connection-specific. */
   slot_name_prefix: string;
+  parameters: Record<string, number | string | boolean | null>;
 };
diff --git a/packages/sync-rules/package.json b/packages/sync-rules/package.json
index bb942b1e8..727188bb6 100644
--- a/packages/sync-rules/package.json
+++ b/packages/sync-rules/package.json
@@ -15,10 +15,9 @@
   "type": "module",
   "scripts": {
     "clean": "rm -r ./dist && tsc -b --clean",
-    "build": "tsc -b",
+    "build:tsc": "tsc -b",
+    "build": "pnpm build:tsc && node scripts/compile-schema.js",
     "build:tests": "tsc -b test/tsconfig.json",
-    "compile:schema": "pnpm build && node scripts/compile-schema.js",
-    "postversion": "pnpm compile:schema",
     "test": "vitest"
   },
   "dependencies": {
diff --git a/packages/types/src/config/PowerSyncConfig.ts b/packages/types/src/config/PowerSyncConfig.ts
index e9dff54f4..dbd33e1ae 100644
--- a/packages/types/src/config/PowerSyncConfig.ts
+++ b/packages/types/src/config/PowerSyncConfig.ts
@@ -135,7 +135,9 @@ export const powerSyncConfig = t.object({
       disable_telemetry_sharing: t.boolean,
       internal_service_endpoint: t.string.optional()
     })
-    .optional()
+    .optional(),
+
+  parameters: t.record(t.number.or(t.string).or(t.boolean).or(t.Null)).optional()
 });
 
 export type PowerSyncConfig = t.Decoded<typeof powerSyncConfig>;
diff --git a/service/Dockerfile b/service/Dockerfile
index 715931b11..d6641555e 100644
--- a/service/Dockerfile
+++ b/service/Dockerfile
@@ -29,6 +29,7 @@ COPY packages/jpgwire/src packages/jpgwire/src/
 COPY packages/jpgwire/ca packages/jpgwire/ca/
 COPY packages/jsonbig/src packages/jsonbig/src/
 COPY packages/sync-rules/src packages/sync-rules/src/
+COPY packages/sync-rules/scripts packages/sync-rules/scripts/
 COPY packages/rsocket-router/src packages/rsocket-router/src/
 COPY packages/types/src packages/types/src/