diff --git a/yarn-project/circuit-types/src/contract_dao.test.ts b/yarn-project/circuit-types/src/contract_dao.test.ts
deleted file mode 100644
index e8bfe08be0c..00000000000
--- a/yarn-project/circuit-types/src/contract_dao.test.ts
+++ /dev/null
@@ -1,56 +0,0 @@
-import { ABIParameterVisibility, ContractArtifact, FunctionSelector, FunctionType } from '@aztec/foundation/abi';
-
-import { ContractDao } from './contract_dao.js';
-import { randomContractArtifact, randomContractInstanceWithAddress } from './mocks.js';
-
-describe('ContractDao', () => {
-  it('serializes / deserializes correctly', () => {
-    const artifact = randomContractArtifact();
-    const dao = new ContractDao(artifact, randomContractInstanceWithAddress());
-
-    expect(ContractDao.fromBuffer(dao.toBuffer())).toEqual(dao);
-  });
-
-  it('extracts function data', () => {
-    const artifact: ContractArtifact = {
-      name: 'test',
-      functions: [
-        {
-          name: 'bar',
-          isInitializer: false,
-          functionType: FunctionType.SECRET,
-          isInternal: false,
-          parameters: [
-            {
-              name: 'value',
-              type: {
-                kind: 'field',
-              },
-              visibility: ABIParameterVisibility.PUBLIC,
-            },
-            {
-              name: 'value',
-              type: {
-                kind: 'field',
-              },
-              visibility: ABIParameterVisibility.SECRET,
-            },
-          ],
-          returnTypes: [],
-          bytecode: '0af',
-          debugSymbols: '',
-        },
-      ],
-      events: [],
-      fileMap: {},
-    };
-
-    const dao = new ContractDao(artifact, randomContractInstanceWithAddress());
-
-    expect(dao.functions[0]).toEqual({
-      ...artifact.functions[0],
-      // number representing bar((Field),Field)
-      selector: new FunctionSelector(4138634513),
-    });
-  });
-});
diff --git a/yarn-project/circuit-types/src/contract_dao.ts b/yarn-project/circuit-types/src/contract_dao.ts
deleted file mode 100644
index b24b45e5515..00000000000
--- a/yarn-project/circuit-types/src/contract_dao.ts
+++ /dev/null
@@ -1,78 +0,0 @@
-import { AztecAddress, ContractFunctionDao } from '@aztec/circuits.js';
-import {
-  ContractArtifact,
-  DebugFileMap,
-  EventAbi,
-  FunctionDebugMetadata,
-  FunctionSelector,
-  getFunctionDebugMetadata,
-} from '@aztec/foundation/abi';
-import { BufferReader, prefixBufferWithLength } from '@aztec/foundation/serialize';
-import { ContractInstanceWithAddress, SerializableContractInstance } from '@aztec/types/contracts';
-
-/**
- * A contract Data Access Object (DAO).
- * Contains the contract's address, portal contract address, and an array of ContractFunctionDao objects.
- * Each ContractFunctionDao object includes FunctionAbi data and the function selector buffer.
- */
-export class ContractDao implements ContractArtifact {
-  /** An array of contract functions with additional selector property.  */
-  public readonly functions: ContractFunctionDao[];
-
-  constructor(private contractArtifact: ContractArtifact, public readonly instance: ContractInstanceWithAddress) {
-    this.functions = contractArtifact.functions.map(f => ({
-      ...f,
-      selector: FunctionSelector.fromNameAndParameters(f.name, f.parameters),
-    }));
-  }
-
-  get aztecNrVersion() {
-    return this.contractArtifact.aztecNrVersion;
-  }
-
-  get name(): string {
-    return this.contractArtifact.name;
-  }
-
-  get events(): EventAbi[] {
-    return this.contractArtifact.events;
-  }
-
-  get fileMap(): DebugFileMap {
-    return this.contractArtifact.fileMap;
-  }
-
-  getFunctionArtifact(selector: FunctionSelector): ContractFunctionDao | undefined {
-    return this.functions.find(f => f.selector.equals(selector));
-  }
-
-  getFunctionArtifactByName(functionName: string): ContractFunctionDao | undefined {
-    return this.functions.find(f => f.name === functionName);
-  }
-
-  getFunctionDebugMetadataByName(functionName: string): FunctionDebugMetadata | undefined {
-    const fn = this.getFunctionArtifactByName(functionName);
-    return fn && getFunctionDebugMetadata(this, fn);
-  }
-
-  toBuffer(): Buffer {
-    // the contract artifact was originally emitted to a JSON file by Noir
-    // should be safe to JSON.stringify it (i.e. it doesn't contain BigInts)
-    const contractArtifactJson = JSON.stringify(this.contractArtifact);
-    const buf = Buffer.concat([
-      this.instance.address.toBuffer(),
-      new SerializableContractInstance(this.instance).toBuffer(),
-      prefixBufferWithLength(Buffer.from(contractArtifactJson, 'utf-8')),
-    ]);
-
-    return buf;
-  }
-
-  static fromBuffer(buf: Uint8Array | BufferReader) {
-    const reader = BufferReader.asReader(buf);
-    const address = AztecAddress.fromBuffer(reader);
-    const instance = SerializableContractInstance.fromBuffer(reader).withAddress(address);
-    const contractArtifact = JSON.parse(reader.readString());
-    return new ContractDao(contractArtifact, instance);
-  }
-}
diff --git a/yarn-project/circuit-types/src/contract_database.ts b/yarn-project/circuit-types/src/contract_database.ts
deleted file mode 100644
index f9b8581febb..00000000000
--- a/yarn-project/circuit-types/src/contract_database.ts
+++ /dev/null
@@ -1,33 +0,0 @@
-import { AztecAddress } from '@aztec/foundation/aztec-address';
-
-import { ContractDao } from './contract_dao.js';
-
-/**
- * Represents a ContractDatabase interface for managing Aztec.nr contracts.
- * Provides methods for adding and retrieving ContractDao objects by their associated addresses.
- */
-export interface ContractDatabase {
-  /**
-   * Adds a new ContractDao instance to the contract database.
-   * The function stores the contract in an array and returns a resolved promise indicating successful addition.
-   *
-   * @param contract - The ContractDao instance to be added.
-   * @returns A Promise that resolves when the contract is successfully added.
-   */
-  addContract(contract: ContractDao): Promise<void>;
-
-  /**
-   * Retrieve a ContractDao instance with the specified AztecAddress.
-   * Returns the first match found or undefined if no contract with the given address is found.
-   *
-   * @param address - The AztecAddress to search for in the stored contracts.
-   * @returns A Promise resolving to the ContractDao instance matching the given address or undefined.
-   */
-  getContract(address: AztecAddress): Promise<ContractDao | undefined>;
-
-  /**
-   * Retrieve all ContractDao instances stored in the database.
-   * @returns A Promise resolving to an array of all stored ContractDao instances.
-   */
-  getContracts(): Promise<ContractDao[]>;
-}
diff --git a/yarn-project/circuit-types/src/index.ts b/yarn-project/circuit-types/src/index.ts
index d627698950e..e1b11878873 100644
--- a/yarn-project/circuit-types/src/index.ts
+++ b/yarn-project/circuit-types/src/index.ts
@@ -1,5 +1,3 @@
-export * from './contract_dao.js';
-export * from './contract_database.js';
 export * from './contract_data.js';
 export * from './function_call.js';
 export * from './keys/index.js';
diff --git a/yarn-project/foundation/src/abi/function_selector.ts b/yarn-project/foundation/src/abi/function_selector.ts
index fc0eaae752b..9ffcc958883 100644
--- a/yarn-project/foundation/src/abi/function_selector.ts
+++ b/yarn-project/foundation/src/abi/function_selector.ts
@@ -21,13 +21,20 @@ export class FunctionSelector extends Selector {
    * Checks if this function selector is equal to another.
    * @returns True if the function selectors are equal.
    */
+  equals(fn: { name: string; parameters: ABIParameter[] }): boolean;
   equals(otherName: string, otherParams: ABIParameter[]): boolean;
   equals(other: FunctionSelector): boolean;
-  equals(other: FunctionSelector | string, otherParams?: ABIParameter[]): boolean {
+  equals(
+    other: FunctionSelector | string | { name: string; parameters: ABIParameter[] },
+    otherParams?: ABIParameter[],
+  ): boolean {
     if (typeof other === 'string') {
       return this.equals(FunctionSelector.fromNameAndParameters(other, otherParams!));
+    } else if (typeof other === 'object' && 'name' in other) {
+      return this.equals(FunctionSelector.fromNameAndParameters(other.name, other.parameters));
+    } else {
+      return this.value === other.value;
     }
-    return this.value === other.value;
   }
 
   /**
diff --git a/yarn-project/pxe/src/contract_data_oracle/index.ts b/yarn-project/pxe/src/contract_data_oracle/index.ts
index 0a2f6519524..ad51ed876c9 100644
--- a/yarn-project/pxe/src/contract_data_oracle/index.ts
+++ b/yarn-project/pxe/src/contract_data_oracle/index.ts
@@ -1,12 +1,11 @@
-import { ContractDatabase } from '@aztec/circuit-types';
+import { AztecAddress, MembershipWitness, VK_TREE_HEIGHT } from '@aztec/circuits.js';
 import {
-  AztecAddress,
-  ContractFunctionDao,
-  MembershipWitness,
-  VK_TREE_HEIGHT,
-  getContractClassFromArtifact,
-} from '@aztec/circuits.js';
-import { FunctionDebugMetadata, FunctionSelector } from '@aztec/foundation/abi';
+  ContractArtifact,
+  FunctionArtifact,
+  FunctionDebugMetadata,
+  FunctionSelector,
+  getFunctionDebugMetadata,
+} from '@aztec/foundation/abi';
 import { Fr } from '@aztec/foundation/fields';
 import { ContractClassNotFoundError, ContractNotFoundError } from '@aztec/simulator';
 import { ContractClass, ContractInstance } from '@aztec/types/contracts';
@@ -23,27 +22,34 @@ import { PrivateFunctionsTree } from './private_functions_tree.js';
  * the required information and facilitate cryptographic proof generation.
  */
 export class ContractDataOracle {
-  private trees: PrivateFunctionsTree[] = [];
+  /** Map from contract class id to private function tree. */
+  private contractClasses: Map<string, PrivateFunctionsTree> = new Map();
+  /** Map from address to contract instance. */
+  private contractInstances: Map<string, ContractInstance> = new Map();
 
-  constructor(private db: ContractDatabase & ContractArtifactDatabase & ContractInstanceDatabase) {}
+  constructor(private db: ContractArtifactDatabase & ContractInstanceDatabase) {}
 
   /** Returns a contract instance for a given address. Throws if not found. */
   public async getContractInstance(contractAddress: AztecAddress): Promise<ContractInstance> {
-    const instance = await this.db.getContractInstance(contractAddress);
-    if (!instance) {
-      throw new ContractNotFoundError(contractAddress.toString());
+    if (!this.contractInstances.has(contractAddress.toString())) {
+      const instance = await this.db.getContractInstance(contractAddress);
+      if (!instance) {
+        throw new ContractNotFoundError(contractAddress.toString());
+      }
+      this.contractInstances.set(contractAddress.toString(), instance);
     }
-    return instance;
+    return this.contractInstances.get(contractAddress.toString())!;
   }
 
-  /** Returns a contract class for a given id. Throws if not found. */
+  /** Returns a contract class for a given class id. Throws if not found. */
   public async getContractClass(contractClassId: Fr): Promise<ContractClass> {
-    const contractArtifact = await this.db.getContractArtifact(contractClassId);
-    if (!contractArtifact) {
-      throw new ContractClassNotFoundError(contractClassId.toString());
-    }
-    // TODO(@spalladino): Cache this computation using the trees.
-    return getContractClassFromArtifact(contractArtifact);
+    const tree = await this.getTreeForClassId(contractClassId);
+    return tree.getContractClass();
+  }
+
+  public async getContractArtifact(contractClassId: Fr): Promise<ContractArtifact> {
+    const tree = await this.getTreeForClassId(contractClassId);
+    return tree.getArtifact();
   }
 
   /**
@@ -56,8 +62,8 @@ export class ContractDataOracle {
    * @returns A Promise that resolves to the portal contract address.
    */
   public async getPortalContractAddress(contractAddress: AztecAddress) {
-    const tree = await this.getTree(contractAddress);
-    return tree.contract.instance.portalContractAddress;
+    const instance = await this.getContractInstance(contractAddress);
+    return instance.portalContractAddress;
   }
 
   /**
@@ -70,7 +76,7 @@ export class ContractDataOracle {
    * @returns The corresponding function's artifact as an object.
    */
   public async getFunctionArtifact(contractAddress: AztecAddress, selector: FunctionSelector) {
-    const tree = await this.getTree(contractAddress);
+    const tree = await this.getTreeForAddress(contractAddress);
     return tree.getFunctionArtifact(selector);
   }
 
@@ -86,9 +92,9 @@ export class ContractDataOracle {
   public async getFunctionArtifactByName(
     contractAddress: AztecAddress,
     functionName: string,
-  ): Promise<ContractFunctionDao | undefined> {
-    const tree = await this.getTree(contractAddress);
-    return tree.contract.getFunctionArtifactByName(functionName);
+  ): Promise<FunctionArtifact | undefined> {
+    const tree = await this.getTreeForAddress(contractAddress);
+    return tree.getArtifact().functions.find(f => f.name === functionName);
   }
 
   /**
@@ -105,14 +111,9 @@ export class ContractDataOracle {
     contractAddress: AztecAddress,
     selector: FunctionSelector,
   ): Promise<FunctionDebugMetadata | undefined> {
-    const tree = await this.getTree(contractAddress);
-    const functionArtifact = tree.contract.getFunctionArtifact(selector);
-
-    if (!functionArtifact) {
-      return undefined;
-    }
-
-    return tree.contract.getFunctionDebugMetadataByName(functionArtifact.name);
+    const tree = await this.getTreeForAddress(contractAddress);
+    const artifact = tree.getFunctionArtifact(selector);
+    return getFunctionDebugMetadata(tree.getArtifact(), artifact);
   }
 
   /**
@@ -126,7 +127,7 @@ export class ContractDataOracle {
    * @throws Error if the contract address is unknown or not found.
    */
   public async getBytecode(contractAddress: AztecAddress, selector: FunctionSelector) {
-    const tree = await this.getTree(contractAddress);
+    const tree = await this.getTreeForAddress(contractAddress);
     return tree.getBytecode(selector);
   }
 
@@ -140,7 +141,7 @@ export class ContractDataOracle {
    * @returns A promise that resolves with the MembershipWitness instance for the specified contract's function.
    */
   public async getFunctionMembershipWitness(contractAddress: AztecAddress, selector: FunctionSelector) {
-    const tree = await this.getTree(contractAddress);
+    const tree = await this.getTreeForAddress(contractAddress);
     return tree.getFunctionMembershipWitness(selector);
   }
 
@@ -158,6 +159,28 @@ export class ContractDataOracle {
     return await Promise.resolve(MembershipWitness.random(VK_TREE_HEIGHT));
   }
 
+  /**
+   * Retrieve or create a ContractTree instance based on the provided class id.
+   * If an existing tree with the same class id is found in the cache, it will be returned.
+   * Otherwise, a new ContractTree instance will be created using the contract data from the database
+   * and added to the cache before returning.
+   *
+   * @param classId - The class id of the contract for which the ContractTree is required.
+   * @returns A ContractTree instance associated with the specified contract address.
+   * @throws An Error if the contract is not found in the ContractDatabase.
+   */
+  private async getTreeForClassId(classId: Fr): Promise<PrivateFunctionsTree> {
+    if (!this.contractClasses.has(classId.toString())) {
+      const artifact = await this.db.getContractArtifact(classId);
+      if (!artifact) {
+        throw new ContractClassNotFoundError(classId.toString());
+      }
+      const tree = new PrivateFunctionsTree(artifact);
+      this.contractClasses.set(classId.toString(), tree);
+    }
+    return this.contractClasses.get(classId.toString())!;
+  }
+
   /**
    * Retrieve or create a ContractTree instance based on the provided AztecAddress.
    * If an existing tree with the same contract address is found in the cache, it will be returned.
@@ -168,18 +191,8 @@ export class ContractDataOracle {
    * @returns A ContractTree instance associated with the specified contract address.
    * @throws An Error if the contract is not found in the ContractDatabase.
    */
-  private async getTree(contractAddress: AztecAddress): Promise<PrivateFunctionsTree> {
-    // TODO(@spalladino): ContractTree should refer to a class, not an instance!
-    let tree = this.trees.find(t => t.contract.instance.address.equals(contractAddress));
-    if (!tree) {
-      const contract = await this.db.getContract(contractAddress);
-      if (!contract) {
-        throw new ContractNotFoundError(contractAddress.toString());
-      }
-
-      tree = new PrivateFunctionsTree(contract);
-      this.trees.push(tree);
-    }
-    return tree;
+  private async getTreeForAddress(contractAddress: AztecAddress): Promise<PrivateFunctionsTree> {
+    const instance = await this.getContractInstance(contractAddress);
+    return this.getTreeForClassId(instance.contractClassId);
   }
 }
diff --git a/yarn-project/pxe/src/contract_data_oracle/private_functions_tree.ts b/yarn-project/pxe/src/contract_data_oracle/private_functions_tree.ts
index 5ae3ea6b0d1..6ea2e061723 100644
--- a/yarn-project/pxe/src/contract_data_oracle/private_functions_tree.ts
+++ b/yarn-project/pxe/src/contract_data_oracle/private_functions_tree.ts
@@ -1,4 +1,3 @@
-import { ContractDao } from '@aztec/circuit-types';
 import {
   FUNCTION_TREE_HEIGHT,
   MembershipWitness,
@@ -7,7 +6,7 @@ import {
   getContractClassFromArtifact,
 } from '@aztec/circuits.js';
 import { MerkleTree } from '@aztec/circuits.js/merkle';
-import { FunctionSelector } from '@aztec/foundation/abi';
+import { ContractArtifact, FunctionSelector } from '@aztec/foundation/abi';
 import { Fr } from '@aztec/foundation/fields';
 import { assertLength } from '@aztec/foundation/serialize';
 import { ContractClassWithId } from '@aztec/types/contracts';
@@ -20,15 +19,11 @@ import { ContractClassWithId } from '@aztec/types/contracts';
  */
 export class PrivateFunctionsTree {
   private tree?: MerkleTree;
-  private contractClass?: ContractClassWithId;
+  private contractClass: ContractClassWithId;
 
-  constructor(
-    /**
-     * The contract data object containing the artifact and contract address.
-     * TODO(@spalladino) Replace with contract class sourced from db.
-     */
-    public readonly contract: ContractDao,
-  ) {}
+  constructor(private readonly artifact: ContractArtifact) {
+    this.contractClass = getContractClassFromArtifact(artifact);
+  }
 
   /**
    * Retrieve the artifact of a given function.
@@ -39,12 +34,10 @@ export class PrivateFunctionsTree {
    * @returns The artifact object containing relevant information about the targeted function.
    */
   public getFunctionArtifact(selector: FunctionSelector) {
-    const artifact = this.contract.functions.find(f => f.selector.equals(selector));
+    const artifact = this.artifact.functions.find(f => selector.equals(f.name, f.parameters));
     if (!artifact) {
       throw new Error(
-        `Unknown function. Selector ${selector.toString()} not found in the artifact of contract ${this.contract.instance.address.toString()}. Expected one of: ${this.contract.functions
-          .map(f => `${f.name} (${f.selector.toString()})`)
-          .join(', ')}`,
+        `Unknown function. Selector ${selector.toString()} not found in the artifact with class ${this.getContractClassId().toString()}.`,
       );
     }
     return artifact;
@@ -75,12 +68,14 @@ export class PrivateFunctionsTree {
 
   /** Returns the contract class object. */
   public getContractClass() {
-    if (!this.contractClass) {
-      this.contractClass = getContractClassFromArtifact(this.contract);
-    }
     return this.contractClass;
   }
 
+  /** Returns the contract artifact. */
+  public getArtifact() {
+    return this.artifact;
+  }
+
   /**
    * Returns the contract class identifier for the given artifact.
    */
diff --git a/yarn-project/pxe/src/contract_database/index.ts b/yarn-project/pxe/src/contract_database/index.ts
deleted file mode 100644
index b33e27be513..00000000000
--- a/yarn-project/pxe/src/contract_database/index.ts
+++ /dev/null
@@ -1 +0,0 @@
-export * from './memory_contract_database.js';
diff --git a/yarn-project/pxe/src/contract_database/memory_contract_database.ts b/yarn-project/pxe/src/contract_database/memory_contract_database.ts
deleted file mode 100644
index 567256def0f..00000000000
--- a/yarn-project/pxe/src/contract_database/memory_contract_database.ts
+++ /dev/null
@@ -1,58 +0,0 @@
-import { ContractDao, ContractDatabase } from '@aztec/circuit-types';
-import { FunctionSelector } from '@aztec/circuits.js';
-import { AztecAddress } from '@aztec/foundation/aztec-address';
-import { DebugLogger } from '@aztec/foundation/log';
-
-/**
- * The MemoryContractDatabase class serves as an in-memory implementation of the ContractDatabase interface.
- * It allows for storing and retrieving contract data, such as ContractDao objects and associated function bytecodes,
- * within a contracts array. This class is particularly useful for testing and development purposes where a
- * persistent storage may not be required.
- */
-export class MemoryContractDatabase implements ContractDatabase {
-  private contracts: ContractDao[] = [];
-
-  constructor(protected log: DebugLogger) {}
-
-  /**
-   * Adds a new ContractDao instance to the memory-based contract database.
-   * The function stores the contract in an array and returns a resolved promise indicating successful addition.
-   *
-   * @param contract - The ContractDao instance to be added to the memory database.
-   * @returns A Promise that resolves when the contract is successfully added.
-   */
-  public addContract(contract: ContractDao) {
-    this.log(`Adding contract ${contract.instance.address.toString()}`);
-    this.contracts.push(contract);
-    return Promise.resolve();
-  }
-
-  /**
-   * Retrieve a ContractDao instance with the specified AztecAddress from the in-memory contracts list.
-   * Returns the first match found or undefined if no contract with the given address is found.
-   *
-   * @param address - The AztecAddress to search for in the stored contracts.
-   * @returns A Promise resolving to the ContractDao instance matching the given address or undefined.
-   */
-  public getContract(address: AztecAddress): Promise<ContractDao | undefined> {
-    return Promise.resolve(this.contracts.find(c => c.instance.address.equals(address)));
-  }
-
-  public getContracts(): Promise<ContractDao[]> {
-    return Promise.resolve(this.contracts);
-  }
-
-  /**
-   * Retrieve the bytecode associated with a given contract address and function selector.
-   * This function searches through the stored contracts to find a matching contract and function,
-   * then returns the corresponding bytecode. If no match is found, it returns undefined.
-   *
-   * @param contractAddress - The AztecAddress representing the contract address to look for.
-   * @param selector - The function selector.
-   * @returns A Promise that resolves to the bytecode of the matching function or undefined if not found.
-   */
-  public async getCode(contractAddress: AztecAddress, selector: FunctionSelector) {
-    const contract = await this.getContract(contractAddress);
-    return contract?.functions.find(f => f.selector.equals(selector))?.bytecode;
-  }
-}
diff --git a/yarn-project/pxe/src/database/contracts/contract_instance_db.ts b/yarn-project/pxe/src/database/contracts/contract_instance_db.ts
index 30dd44bed9e..0fbd0696384 100644
--- a/yarn-project/pxe/src/database/contracts/contract_instance_db.ts
+++ b/yarn-project/pxe/src/database/contracts/contract_instance_db.ts
@@ -15,4 +15,7 @@ export interface ContractInstanceDatabase {
    * @param address - Address of the contract.
    */
   getContractInstance(address: AztecAddress): Promise<ContractInstanceWithAddress | undefined>;
+
+  /** Returns the addresses all contract instances registered in the DB. */
+  getContractsAddresses(): Promise<AztecAddress[]>;
 }
diff --git a/yarn-project/pxe/src/database/kv_pxe_database.ts b/yarn-project/pxe/src/database/kv_pxe_database.ts
index c63b913ea77..8fabdf14872 100644
--- a/yarn-project/pxe/src/database/kv_pxe_database.ts
+++ b/yarn-project/pxe/src/database/kv_pxe_database.ts
@@ -1,4 +1,4 @@
-import { ContractDao, MerkleTreeId, NoteFilter, NoteStatus, PublicKey } from '@aztec/circuit-types';
+import { MerkleTreeId, NoteFilter, NoteStatus, PublicKey } from '@aztec/circuit-types';
 import { AztecAddress, CompleteAddress, Header } from '@aztec/circuits.js';
 import { ContractArtifact } from '@aztec/foundation/abi';
 import { toBufferBE } from '@aztec/foundation/bigint-buffer';
@@ -20,7 +20,6 @@ export class KVPxeDatabase implements PxeDatabase {
   #addressIndex: AztecMap<string, number>;
   #authWitnesses: AztecMap<string, Buffer[]>;
   #capsules: AztecArray<Buffer[]>;
-  #contracts: AztecMap<string, Buffer>;
   #notes: AztecMap<string, Buffer>;
   #nullifiedNotes: AztecMap<string, Buffer>;
   #nullifierToNoteId: AztecMap<string, string>;
@@ -47,7 +46,6 @@ export class KVPxeDatabase implements PxeDatabase {
 
     this.#authWitnesses = db.openMap('auth_witnesses');
     this.#capsules = db.openArray('capsules');
-    this.#contracts = db.openMap('contracts');
 
     this.#contractArtifacts = db.openMap('contract_artifacts');
     this.#contractInstances = db.openMap('contracts_instances');
@@ -73,11 +71,22 @@ export class KVPxeDatabase implements PxeDatabase {
     this.#deferredNotesByContract = db.openMultiMap('deferred_notes_by_contract');
   }
 
+  public async getContract(
+    address: AztecAddress,
+  ): Promise<(ContractInstanceWithAddress & ContractArtifact) | undefined> {
+    const instance = await this.getContractInstance(address);
+    const artifact = instance && (await this.getContractArtifact(instance?.contractClassId));
+    if (!instance || !artifact) {
+      return undefined;
+    }
+    return { ...instance, ...artifact };
+  }
+
   public async addContractArtifact(id: Fr, contract: ContractArtifact): Promise<void> {
     await this.#contractArtifacts.set(id.toString(), contractArtifactToBuffer(contract));
   }
 
-  getContractArtifact(id: Fr): Promise<ContractArtifact | undefined> {
+  public getContractArtifact(id: Fr): Promise<ContractArtifact | undefined> {
     const contract = this.#contractArtifacts.get(id.toString());
     // TODO(@spalladino): AztecMap lies and returns Uint8Arrays instead of Buffers, hence the extra Buffer.from.
     return Promise.resolve(contract && contractArtifactFromBuffer(Buffer.from(contract)));
@@ -95,6 +104,10 @@ export class KVPxeDatabase implements PxeDatabase {
     return Promise.resolve(contract && SerializableContractInstance.fromBuffer(contract).withAddress(address));
   }
 
+  getContractsAddresses(): Promise<AztecAddress[]> {
+    return Promise.resolve(Array.from(this.#contractInstances.keys()).map(AztecAddress.fromString));
+  }
+
   async addAuthWitness(messageHash: Fr, witness: Fr[]): Promise<void> {
     await this.#authWitnesses.set(
       messageHash.toString(),
@@ -393,17 +406,4 @@ export class KVPxeDatabase implements PxeDatabase {
 
     return notesSize + treeRootsSize + authWitsSize + addressesSize;
   }
-
-  async addContract(contract: ContractDao): Promise<void> {
-    await this.#contracts.set(contract.instance.address.toString(), contract.toBuffer());
-  }
-
-  getContract(address: AztecAddress): Promise<ContractDao | undefined> {
-    const contract = this.#contracts.get(address.toString());
-    return Promise.resolve(contract ? ContractDao.fromBuffer(contract) : undefined);
-  }
-
-  getContracts(): Promise<ContractDao[]> {
-    return Promise.resolve(Array.from(this.#contracts.values()).map(c => ContractDao.fromBuffer(c)));
-  }
 }
diff --git a/yarn-project/pxe/src/database/pxe_database.ts b/yarn-project/pxe/src/database/pxe_database.ts
index f97847dfe97..a755f710331 100644
--- a/yarn-project/pxe/src/database/pxe_database.ts
+++ b/yarn-project/pxe/src/database/pxe_database.ts
@@ -1,7 +1,9 @@
-import { ContractDatabase, NoteFilter } from '@aztec/circuit-types';
+import { NoteFilter } from '@aztec/circuit-types';
 import { CompleteAddress, Header, PublicKey } from '@aztec/circuits.js';
+import { ContractArtifact } from '@aztec/foundation/abi';
 import { AztecAddress } from '@aztec/foundation/aztec-address';
 import { Fr } from '@aztec/foundation/fields';
+import { ContractInstanceWithAddress } from '@aztec/types/contracts';
 
 import { ContractArtifactDatabase } from './contracts/contract_artifact_db.js';
 import { ContractInstanceDatabase } from './contracts/contract_instance_db.js';
@@ -12,7 +14,9 @@ import { NoteDao } from './note_dao.js';
  * A database interface that provides methods for retrieving, adding, and removing transactional data related to Aztec
  * addresses, storage slots, and nullifiers.
  */
-export interface PxeDatabase extends ContractDatabase, ContractArtifactDatabase, ContractInstanceDatabase {
+export interface PxeDatabase extends ContractArtifactDatabase, ContractInstanceDatabase {
+  getContract(address: AztecAddress): Promise<(ContractInstanceWithAddress & ContractArtifact) | undefined>;
+
   /**
    * Add a auth witness to the database.
    * @param messageHash - The message hash.
diff --git a/yarn-project/pxe/src/pxe_service/pxe_service.ts b/yarn-project/pxe/src/pxe_service/pxe_service.ts
index f9bdb5c9bf2..9f4b68afa11 100644
--- a/yarn-project/pxe/src/pxe_service/pxe_service.ts
+++ b/yarn-project/pxe/src/pxe_service/pxe_service.ts
@@ -1,7 +1,6 @@
 import {
   AuthWitness,
   AztecNode,
-  ContractDao,
   ContractData,
   DeployedContract,
   ExtendedNote,
@@ -39,7 +38,7 @@ import {
   getContractClassFromArtifact,
 } from '@aztec/circuits.js';
 import { computeCommitmentNonce, siloNullifier } from '@aztec/circuits.js/hash';
-import { DecodedReturn, encodeArguments } from '@aztec/foundation/abi';
+import { DecodedReturn, FunctionSelector, encodeArguments } from '@aztec/foundation/abi';
 import { arrayNonEmptyLength, padArrayEnd } from '@aztec/foundation/collection';
 import { Fr } from '@aztec/foundation/fields';
 import { SerialQueue } from '@aztec/foundation/fifo';
@@ -218,31 +217,21 @@ export class PXEService implements PXE {
   }
 
   public async addContracts(contracts: DeployedContract[]) {
-    const contractDaos = contracts.map(c => new ContractDao(c.artifact, c.instance));
-    await Promise.all(contractDaos.map(c => this.db.addContract(c)));
-    await this.addArtifactsAndInstancesFromDeployedContracts(contracts);
-    for (const contract of contractDaos) {
-      const instance = contract.instance;
-      const contractAztecAddress = instance.address;
-      const hasPortal = instance.portalContractAddress && !instance.portalContractAddress.isZero();
-      const portalInfo = hasPortal ? ` with portal ${instance.portalContractAddress.toChecksumString()}` : '';
-      this.log.info(`Added contract ${contract.name} at ${contractAztecAddress}${portalInfo}`);
-      await this.synchronizer.reprocessDeferredNotesForContract(contractAztecAddress);
-    }
-  }
-
-  private async addArtifactsAndInstancesFromDeployedContracts(contracts: DeployedContract[]) {
     for (const contract of contracts) {
-      const artifact = contract.artifact;
+      const { instance, artifact } = contract;
       const artifactHash = computeArtifactHash(artifact);
       const contractClassId = computeContractClassId(getContractClassFromArtifact({ ...artifact, artifactHash }));
       await this.db.addContractArtifact(contractClassId, artifact);
-      await this.db.addContractInstance(contract.instance);
+      await this.db.addContractInstance(instance);
+      const hasPortal = instance.portalContractAddress && !instance.portalContractAddress.isZero();
+      const portalInfo = hasPortal ? ` with portal ${instance.portalContractAddress.toChecksumString()}` : '';
+      this.log.info(`Added contract ${artifact.name} at ${instance.address.toString()}${portalInfo}`);
+      await this.synchronizer.reprocessDeferredNotesForContract(instance.address);
     }
   }
 
-  public async getContracts(): Promise<AztecAddress[]> {
-    return (await this.db.getContracts()).map(c => c.instance.address);
+  public getContracts(): Promise<AztecAddress[]> {
+    return this.db.getContractsAddresses();
   }
 
   public async getPublicStorageAt(contract: AztecAddress, slot: Fr) {
@@ -649,9 +638,13 @@ export class PXEService implements PXE {
         if (contract) {
           err.enrichWithContractName(parsedContractAddress, contract.name);
           selectors.forEach(selector => {
-            const functionArtifact = contract.functions.find(f => f.selector.toString() === selector);
+            const functionArtifact = contract.functions.find(f => FunctionSelector.fromString(selector).equals(f));
             if (functionArtifact) {
-              err.enrichWithFunctionName(parsedContractAddress, functionArtifact.selector, functionArtifact.name);
+              err.enrichWithFunctionName(
+                parsedContractAddress,
+                FunctionSelector.fromNameAndParameters(functionArtifact),
+                functionArtifact.name,
+              );
             }
           });
         }
diff --git a/yarn-project/pxe/src/simulator_oracle/index.ts b/yarn-project/pxe/src/simulator_oracle/index.ts
index b105f4a1e8a..63f84b0e970 100644
--- a/yarn-project/pxe/src/simulator_oracle/index.ts
+++ b/yarn-project/pxe/src/simulator_oracle/index.ts
@@ -16,7 +16,7 @@ import {
   Header,
   L1_TO_L2_MSG_TREE_HEIGHT,
 } from '@aztec/circuits.js';
-import { FunctionArtifactWithDebugMetadata } from '@aztec/foundation/abi';
+import { FunctionArtifactWithDebugMetadata, getFunctionArtifactWithDebugMetadata } from '@aztec/foundation/abi';
 import { createDebugLogger } from '@aztec/foundation/log';
 import { DBOracle, KeyPair, MessageLoadOracleInputs } from '@aztec/simulator';
 import { ContractInstance } from '@aztec/types/contracts';
@@ -111,16 +111,9 @@ export class SimulatorOracle implements DBOracle {
     contractAddress: AztecAddress,
     functionName: string,
   ): Promise<FunctionArtifactWithDebugMetadata | undefined> {
-    const artifact = await this.contractDataOracle.getFunctionArtifactByName(contractAddress, functionName);
-    if (!artifact) {
-      return;
-    }
-
-    const debug = await this.contractDataOracle.getFunctionDebugMetadata(contractAddress, artifact.selector);
-    return {
-      ...artifact,
-      debug,
-    };
+    const instance = await this.contractDataOracle.getContractInstance(contractAddress);
+    const artifact = await this.contractDataOracle.getContractArtifact(instance.contractClassId);
+    return artifact && getFunctionArtifactWithDebugMetadata(artifact, functionName);
   }
 
   async getPortalContractAddress(contractAddress: AztecAddress): Promise<EthAddress> {