AztecProtocol · PhilWindle · Feb 14, 2026 · Feb 13, 2026
diff --git a/yarn-project/archiver/src/archiver-sync.test.ts b/yarn-project/archiver/src/archiver-sync.test.ts
@@ -30,6 +30,7 @@ import { Archiver, type ArchiverEmitter } from './archiver.js';
 import type { ArchiverInstrumentation } from './modules/instrumentation.js';
 import { ArchiverL1Synchronizer } from './modules/l1_synchronizer.js';
 import { KVArchiverDataStore } from './store/kv_archiver_store.js';
+import { L2TipsCache } from './store/l2_tips_cache.js';
 import { FakeL1State } from './test/fake_l1_state.js';
 
 describe('Archiver Sync', () => {
@@ -116,6 +117,9 @@ describe('Archiver Sync', () => {
     // Create event emitter shared by archiver and synchronizer
     const events = new EventEmitter() as ArchiverEmitter;
 
+    // Create L2 tips cache shared by archiver and synchronizer
+    const l2TipsCache = new L2TipsCache(archiverStore.blockStore);
+
     // Create the L1 synchronizer
     synchronizer = new ArchiverL1Synchronizer(
       publicClient,
@@ -132,6 +136,7 @@ describe('Archiver Sync', () => {
       l1Constants,
       events,
       instrumentation.tracer,
+      l2TipsCache,
       syncLogger,
     );
 
@@ -147,6 +152,7 @@ describe('Archiver Sync', () => {
       l1Constants,
       synchronizer,
       events,
+      l2TipsCache,
     );
   });
 

diff --git a/yarn-project/archiver/src/archiver.ts b/yarn-project/archiver/src/archiver.ts
@@ -1,5 +1,4 @@
 import type { BlobClientInterface } from '@aztec/blob-client/client';
-import { GENESIS_BLOCK_HEADER_HASH, INITIAL_L2_BLOCK_NUM } from '@aztec/constants';
 import { EpochCache } from '@aztec/epoch-cache';
 import { BlockTagTooOldError, RollupContract } from '@aztec/ethereum/contracts';
 import type { L1ContractAddresses } from '@aztec/ethereum/l1-contract-addresses';
@@ -15,8 +14,6 @@ import { RunningPromise, makeLoggingErrorHandler } from '@aztec/foundation/runni
 import { DateProvider } from '@aztec/foundation/timer';
 import {
   type ArchiverEmitter,
-  type CheckpointId,
-  GENESIS_CHECKPOINT_HEADER_HASH,
   L2Block,
   type L2BlockSink,
   type L2Tips,
@@ -41,6 +38,7 @@ import { ArchiverDataStoreUpdater } from './modules/data_store_updater.js';
 import type { ArchiverInstrumentation } from './modules/instrumentation.js';
 import type { ArchiverL1Synchronizer } from './modules/l1_synchronizer.js';
 import type { KVArchiverDataStore } from './store/kv_archiver_store.js';
+import { L2TipsCache } from './store/l2_tips_cache.js';
 
 /** Export ArchiverEmitter for use in factory and tests. */
 export type { ArchiverEmitter };
@@ -83,6 +81,9 @@ export class Archiver extends ArchiverDataSourceBase implements L2BlockSink, Tra
   /** Helper to handle updates to the store */
   private readonly updater: ArchiverDataStoreUpdater;
 
+  /** In-memory cache for L2 chain tips. */
+  private readonly l2TipsCache: L2TipsCache;
+
   public readonly tracer: Tracer;
 
   /**
@@ -122,6 +123,7 @@ export class Archiver extends ArchiverDataSourceBase implements L2BlockSink, Tra
     protected override readonly l1Constants: L1RollupConstants & { l1StartBlockHash: Buffer32; genesisArchiveRoot: Fr },
     synchronizer: ArchiverL1Synchronizer,
     events: ArchiverEmitter,
+    l2TipsCache?: L2TipsCache,
     private readonly log: Logger = createLogger('archiver'),
   ) {
     super(dataStore, l1Constants);
@@ -130,7 +132,8 @@ export class Archiver extends ArchiverDataSourceBase implements L2BlockSink, Tra
     this.initialSyncPromise = promiseWithResolvers();
     this.synchronizer = synchronizer;
     this.events = events;
-    this.updater = new ArchiverDataStoreUpdater(this.dataStore);
+    this.l2TipsCache = l2TipsCache ?? new L2TipsCache(this.dataStore.blockStore);
+    this.updater = new ArchiverDataStoreUpdater(this.dataStore, this.l2TipsCache);
 
     // Running promise starts with a small interval inbetween runs, so all iterations needed for the initial sync
     // are done as fast as possible. This then gets updated once the initial sync completes.
@@ -391,111 +394,8 @@ export class Archiver extends ArchiverDataSourceBase implements L2BlockSink, Tra
     return true;
   }
 
-  public async getL2Tips(): Promise<L2Tips> {
-    const [latestBlockNumber, provenBlockNumber, checkpointedBlockNumber, finalizedBlockNumber] = await Promise.all([
-      this.getBlockNumber(),
-      this.getProvenBlockNumber(),
-      this.getCheckpointedL2BlockNumber(),
-      this.getFinalizedL2BlockNumber(),
-    ] as const);
-
-    const beforeInitialblockNumber = BlockNumber(INITIAL_L2_BLOCK_NUM - 1);
-
-    // Get the latest block header and checkpointed blocks for proven, finalised and checkpointed blocks
-    const [latestBlockHeader, provenCheckpointedBlock, finalizedCheckpointedBlock, checkpointedBlock] =
-      await Promise.all([
-        latestBlockNumber > beforeInitialblockNumber ? this.getBlockHeader(latestBlockNumber) : undefined,
-        provenBlockNumber > beforeInitialblockNumber ? this.getCheckpointedBlock(provenBlockNumber) : undefined,
-        finalizedBlockNumber > beforeInitialblockNumber ? this.getCheckpointedBlock(finalizedBlockNumber) : undefined,
-        checkpointedBlockNumber > beforeInitialblockNumber
-          ? this.getCheckpointedBlock(checkpointedBlockNumber)
-          : undefined,
-      ] as const);
-
-    if (latestBlockNumber > beforeInitialblockNumber && !latestBlockHeader) {
-      throw new Error(`Failed to retrieve latest block header for block ${latestBlockNumber}`);
-    }
-
-    // Checkpointed blocks must exist for proven, finalized and checkpointed tips if they are beyond the initial block number.
-    if (checkpointedBlockNumber > beforeInitialblockNumber && !checkpointedBlock?.block.header) {
-      throw new Error(
-        `Failed to retrieve checkpointed block header for block ${checkpointedBlockNumber} (latest block is ${latestBlockNumber})`,
-      );
-    }
-
-    if (provenBlockNumber > beforeInitialblockNumber && !provenCheckpointedBlock?.block.header) {
-      throw new Error(
-        `Failed to retrieve proven checkpointed for block ${provenBlockNumber} (latest block is ${latestBlockNumber})`,
-      );
-    }
-
-    if (finalizedBlockNumber > beforeInitialblockNumber && !finalizedCheckpointedBlock?.block.header) {
-      throw new Error(
-        `Failed to retrieve finalized block header for block ${finalizedBlockNumber} (latest block is ${latestBlockNumber})`,
-      );
-    }
-
-    const latestBlockHeaderHash = (await latestBlockHeader?.hash()) ?? GENESIS_BLOCK_HEADER_HASH;
-    const provenBlockHeaderHash = (await provenCheckpointedBlock?.block.header?.hash()) ?? GENESIS_BLOCK_HEADER_HASH;
-    const finalizedBlockHeaderHash =
-      (await finalizedCheckpointedBlock?.block.header?.hash()) ?? GENESIS_BLOCK_HEADER_HASH;
-    const checkpointedBlockHeaderHash = (await checkpointedBlock?.block.header?.hash()) ?? GENESIS_BLOCK_HEADER_HASH;
-
-    // Now attempt to retrieve checkpoints for proven, finalised and checkpointed blocks
-    const [[provenBlockCheckpoint], [finalizedBlockCheckpoint], [checkpointedBlockCheckpoint]] = await Promise.all([
-      provenCheckpointedBlock !== undefined
-        ? await this.getCheckpoints(provenCheckpointedBlock?.checkpointNumber, 1)
-        : [undefined],
-      finalizedCheckpointedBlock !== undefined
-        ? await this.getCheckpoints(finalizedCheckpointedBlock?.checkpointNumber, 1)
-        : [undefined],
-      checkpointedBlock !== undefined ? await this.getCheckpoints(checkpointedBlock?.checkpointNumber, 1) : [undefined],
-    ]);
-
-    const initialcheckpointId: CheckpointId = {
-      number: CheckpointNumber.ZERO,
-      hash: GENESIS_CHECKPOINT_HEADER_HASH.toString(),
-    };
-
-    const makeCheckpointId = (checkpoint: PublishedCheckpoint | undefined) => {
-      if (checkpoint === undefined) {
-        return initialcheckpointId;
-      }
-      return {
-        number: checkpoint.checkpoint.number,
-        hash: checkpoint.checkpoint.hash().toString(),
-      };
-    };
-
-    const l2Tips: L2Tips = {
-      proposed: {
-        number: latestBlockNumber,
-        hash: latestBlockHeaderHash.toString(),
-      },
-      proven: {
-        block: {
-          number: provenBlockNumber,
-          hash: provenBlockHeaderHash.toString(),
-        },
-        checkpoint: makeCheckpointId(provenBlockCheckpoint),
-      },
-      finalized: {
-        block: {
-          number: finalizedBlockNumber,
-          hash: finalizedBlockHeaderHash.toString(),
-        },
-        checkpoint: makeCheckpointId(finalizedBlockCheckpoint),
-      },
-      checkpointed: {
-        block: {
-          number: checkpointedBlockNumber,
-          hash: checkpointedBlockHeaderHash.toString(),
-        },
-        checkpoint: makeCheckpointId(checkpointedBlockCheckpoint),
-      },
-    };
-
-    return l2Tips;
+  public getL2Tips(): Promise<L2Tips> {
+    return this.l2TipsCache.getL2Tips();
   }
 
   public async rollbackTo(targetL2BlockNumber: BlockNumber): Promise<void> {
@@ -532,7 +432,7 @@ export class Archiver extends ArchiverDataSourceBase implements L2BlockSink, Tra
     await this.store.setMessageSynchedL1Block({ l1BlockNumber: targetL1BlockNumber, l1BlockHash: targetL1BlockHash });
     if (targetL2BlockNumber < currentProvenBlock) {
       this.log.info(`Clearing proven L2 block number`);
-      await this.store.setProvenCheckpointNumber(CheckpointNumber.ZERO);
+      await this.updater.setProvenCheckpointNumber(CheckpointNumber.ZERO);
     }
     // TODO(palla/reorg): Set the finalized block when we add support for it.
     // if (targetL2BlockNumber < currentFinalizedBlock) {

diff --git a/yarn-project/archiver/src/factory.ts b/yarn-project/archiver/src/factory.ts
@@ -25,6 +25,7 @@ import { type ArchiverConfig, mapArchiverConfig } from './config.js';
 import { ArchiverInstrumentation } from './modules/instrumentation.js';
 import { ArchiverL1Synchronizer } from './modules/l1_synchronizer.js';
 import { ARCHIVER_DB_VERSION, KVArchiverDataStore } from './store/kv_archiver_store.js';
+import { L2TipsCache } from './store/l2_tips_cache.js';
 
 export const ARCHIVER_STORE_NAME = 'archiver';
 
@@ -128,6 +129,9 @@ export async function createArchiver(
   // Create the event emitter that will be shared by archiver and synchronizer
   const events = new EventEmitter() as ArchiverEmitter;
 
+  // Create L2 tips cache shared by archiver and synchronizer
+  const l2TipsCache = new L2TipsCache(archiverStore.blockStore);
+
   // Create the L1 synchronizer
   const synchronizer = new ArchiverL1Synchronizer(
     publicClient,
@@ -144,6 +148,8 @@ export async function createArchiver(
     l1Constants,
     events,
     instrumentation.tracer,
+    l2TipsCache,
+    undefined, // log (use default)
   );
 
   const archiver = new Archiver(
@@ -158,6 +164,7 @@ export async function createArchiver(
     l1Constants,
     synchronizer,
     events,
+    l2TipsCache,
   );
 
   await archiver.start(opts.blockUntilSync);

diff --git a/yarn-project/archiver/src/index.ts b/yarn-project/archiver/src/index.ts
@@ -8,5 +8,6 @@ export * from './config.js';
 export { type L1PublishedData } from './structs/published.js';
 export { KVArchiverDataStore, ARCHIVER_DB_VERSION } from './store/kv_archiver_store.js';
 export { ContractInstanceStore } from './store/contract_instance_store.js';
+export { L2TipsCache } from './store/l2_tips_cache.js';
 
 export { retrieveCheckpointsFromRollup, retrieveL2ProofVerifiedEvents } from './l1/data_retrieval.js';
diff --git a/yarn-project/archiver/src/modules/data_store_updater.ts b/yarn-project/archiver/src/modules/data_store_updater.ts
@@ -25,6 +25,7 @@ import type { UInt64 } from '@aztec/stdlib/types';
 import groupBy from 'lodash.groupby';
 
 import type { KVArchiverDataStore } from '../store/kv_archiver_store.js';
+import type { L2TipsCache } from '../store/l2_tips_cache.js';
 
 /** Operation type for contract data updates. */
 enum Operation {
@@ -44,7 +45,10 @@ type ReconcileCheckpointsResult = {
 export class ArchiverDataStoreUpdater {
   private readonly log = createLogger('archiver:store_updater');
 
-  constructor(private store: KVArchiverDataStore) {}
+  constructor(
+    private store: KVArchiverDataStore,
+    private l2TipsCache?: L2TipsCache,
+  ) {}
 
   /**
    * Adds proposed blocks to the store with contract class/instance extraction from logs.
@@ -56,11 +60,11 @@ export class ArchiverDataStoreUpdater {
    * @param pendingChainValidationStatus - Optional validation status to set.
    * @returns True if the operation is successful.
    */
-  public addProposedBlocks(
+  public async addProposedBlocks(
     blocks: L2Block[],
     pendingChainValidationStatus?: ValidateCheckpointResult,
   ): Promise<boolean> {
-    return this.store.transactionAsync(async () => {
+    const result = await this.store.transactionAsync(async () => {
       await this.store.addProposedBlocks(blocks);
 
       const opResults = await Promise.all([
@@ -72,8 +76,10 @@ export class ArchiverDataStoreUpdater {
         ...blocks.map(block => this.addContractDataToDb(block)),
       ]);
 
+      await this.l2TipsCache?.refresh();
       return opResults.every(Boolean);
     });
+    return result;
   }
 
   /**
@@ -87,11 +93,11 @@ export class ArchiverDataStoreUpdater {
    * @param pendingChainValidationStatus - Optional validation status to set.
    * @returns Result with information about any pruned blocks.
    */
-  public addCheckpoints(
+  public async addCheckpoints(
     checkpoints: PublishedCheckpoint[],
     pendingChainValidationStatus?: ValidateCheckpointResult,
   ): Promise<ReconcileCheckpointsResult> {
-    return this.store.transactionAsync(async () => {
+    const result = await this.store.transactionAsync(async () => {
       // Before adding checkpoints, check for conflicts with local blocks if any
       const { prunedBlocks, lastAlreadyInsertedBlockNumber } = await this.pruneMismatchingLocalBlocks(checkpoints);
 
@@ -111,8 +117,10 @@ export class ArchiverDataStoreUpdater {
         ...newBlocks.map(block => this.addContractDataToDb(block)),
       ]);
 
+      await this.l2TipsCache?.refresh();
       return { prunedBlocks, lastAlreadyInsertedBlockNumber };
     });
+    return result;
   }
 
   /**
@@ -197,8 +205,8 @@ export class ArchiverDataStoreUpdater {
    * @returns The removed blocks.
    * @throws Error if any block to be removed is checkpointed.
    */
-  public removeUncheckpointedBlocksAfter(blockNumber: BlockNumber): Promise<L2Block[]> {
-    return this.store.transactionAsync(async () => {
+  public async removeUncheckpointedBlocksAfter(blockNumber: BlockNumber): Promise<L2Block[]> {
+    const result = await this.store.transactionAsync(async () => {
       // Verify we're only removing uncheckpointed blocks
       const lastCheckpointedBlockNumber = await this.store.getCheckpointedL2BlockNumber();
       if (blockNumber < lastCheckpointedBlockNumber) {
@@ -207,8 +215,11 @@ export class ArchiverDataStoreUpdater {
         );
       }
 
-      return await this.removeBlocksAfter(blockNumber);
+      const result = await this.removeBlocksAfter(blockNumber);
+      await this.l2TipsCache?.refresh();
+      return result;
     });
+    return result;
   }
 
   /**
@@ -238,17 +249,31 @@ export class ArchiverDataStoreUpdater {
    * @returns True if the operation is successful.
    */
   public async removeCheckpointsAfter(checkpointNumber: CheckpointNumber): Promise<boolean> {
-    const { blocksRemoved = [] } = await this.store.removeCheckpointsAfter(checkpointNumber);
-
-    const opResults = await Promise.all([
-      // Prune rolls back to the last proven block, which is by definition valid
-      this.store.setPendingChainValidationStatus({ valid: true }),
-      // Remove contract data for all blocks being removed
-      ...blocksRemoved.map(block => this.removeContractDataFromDb(block)),
-      this.store.deleteLogs(blocksRemoved),
-    ]);
+    return await this.store.transactionAsync(async () => {
+      const { blocksRemoved = [] } = await this.store.removeCheckpointsAfter(checkpointNumber);
+
+      const opResults = await Promise.all([
+        // Prune rolls back to the last proven block, which is by definition valid
+        this.store.setPendingChainValidationStatus({ valid: true }),
+        // Remove contract data for all blocks being removed
+        ...blocksRemoved.map(block => this.removeContractDataFromDb(block)),
+        this.store.deleteLogs(blocksRemoved),
+      ]);
 
-    return opResults.every(Boolean);
+      await this.l2TipsCache?.refresh();
+      return opResults.every(Boolean);
+    });
+  }
+
+  /**
+   * Updates the proven checkpoint number and refreshes the L2 tips cache.
+   * @param checkpointNumber - The checkpoint number to set as proven.
+   */
+  public async setProvenCheckpointNumber(checkpointNumber: CheckpointNumber): Promise<void> {
+    await this.store.transactionAsync(async () => {
+      await this.store.setProvenCheckpointNumber(checkpointNumber);
+      await this.l2TipsCache?.refresh();
+    });
   }
 
   /** Extracts and stores contract data from a single block. */