diff --git a/packages/codegen/src/templates/indexer-template.handlebars b/packages/codegen/src/templates/indexer-template.handlebars
index 4b7d88d1..0a9f8f9f 100644
--- a/packages/codegen/src/templates/indexer-template.handlebars
+++ b/packages/codegen/src/templates/indexer-template.handlebars
@@ -591,7 +591,7 @@ export class Indexer implements IndexerInterface {
         eventInfo = {
           {{#each event.params}}
           {{#if (compare this.type 'bigint')}}
-          {{this.name}}: BigInt(ethers.BigNumber.from({{this.name}}).toString())
+          {{this.name}}: BigInt({{this.name}}.toString())
           {{~else}}
           {{this.name}}
           {{~/if}}
diff --git a/packages/eden-watcher/src/indexer.ts b/packages/eden-watcher/src/indexer.ts
index 843eade6..d98eac70 100644
--- a/packages/eden-watcher/src/indexer.ts
+++ b/packages/eden-watcher/src/indexer.ts
@@ -624,7 +624,7 @@ export class Indexer implements IndexerInterface {
         eventInfo = {
           from,
           to,
-          value: BigInt(ethers.BigNumber.from(value).toString())
+          value: BigInt(value.toString())
         };
 
         break;
@@ -635,7 +635,7 @@ export class Indexer implements IndexerInterface {
         eventInfo = {
           owner,
           spender,
-          value: BigInt(ethers.BigNumber.from(value).toString())
+          value: BigInt(value.toString())
         };
 
         break;
@@ -679,8 +679,8 @@ export class Indexer implements IndexerInterface {
           slot,
           owner,
           delegate,
-          newBidAmount,
-          oldBidAmount,
+          newBidAmount: BigInt(newBidAmount.toString()),
+          oldBidAmount: BigInt(oldBidAmount.toString()),
           taxNumerator,
           taxDenominator
         };
@@ -704,7 +704,7 @@ export class Indexer implements IndexerInterface {
         const { staker, stakeAmount } = logDescription.args;
         eventInfo = {
           staker,
-          stakeAmount: BigInt(ethers.BigNumber.from(stakeAmount).toString())
+          stakeAmount: BigInt(stakeAmount.toString())
         };
 
         break;
@@ -714,7 +714,7 @@ export class Indexer implements IndexerInterface {
         const { staker, unstakedAmount } = logDescription.args;
         eventInfo = {
           staker,
-          unstakedAmount: BigInt(ethers.BigNumber.from(unstakedAmount).toString())
+          unstakedAmount: BigInt(unstakedAmount.toString())
         };
 
         break;
@@ -724,7 +724,7 @@ export class Indexer implements IndexerInterface {
         const { withdrawer, withdrawalAmount } = logDescription.args;
         eventInfo = {
           withdrawer,
-          withdrawalAmount: BigInt(ethers.BigNumber.from(withdrawalAmount).toString())
+          withdrawalAmount: BigInt(withdrawalAmount.toString())
         };
 
         break;
@@ -748,7 +748,7 @@ export class Indexer implements IndexerInterface {
         eventInfo = {
           from,
           to,
-          tokenId: BigInt(ethers.BigNumber.from(tokenId).toString())
+          tokenId: BigInt(tokenId.toString())
         };
 
         break;
@@ -759,7 +759,7 @@ export class Indexer implements IndexerInterface {
         eventInfo = {
           owner,
           approved,
-          tokenId: BigInt(ethers.BigNumber.from(tokenId).toString())
+          tokenId: BigInt(tokenId.toString())
         };
 
         break;
@@ -813,10 +813,10 @@ export class Indexer implements IndexerInterface {
         eventName = logDescription.name;
         const { index, totalEarned, account, claimed } = logDescription.args;
         eventInfo = {
-          index: BigInt(ethers.BigNumber.from(index).toString()),
-          totalEarned: BigInt(ethers.BigNumber.from(totalEarned).toString()),
+          index: BigInt(index.toString()),
+          totalEarned: BigInt(totalEarned.toString()),
           account,
-          claimed: BigInt(ethers.BigNumber.from(claimed).toString())
+          claimed: BigInt(claimed.toString())
         };
 
         break;
@@ -826,7 +826,7 @@ export class Indexer implements IndexerInterface {
         const { account, slashed } = logDescription.args;
         eventInfo = {
           account,
-          slashed: BigInt(ethers.BigNumber.from(slashed).toString())
+          slashed: BigInt(slashed.toString())
         };
 
         break;
@@ -836,7 +836,7 @@ export class Indexer implements IndexerInterface {
         const { merkleRoot, distributionNumber, metadataURI } = logDescription.args;
         eventInfo = {
           merkleRoot,
-          distributionNumber: BigInt(ethers.BigNumber.from(distributionNumber).toString()),
+          distributionNumber: BigInt(distributionNumber.toString()),
           metadataURI
         };
 
@@ -847,8 +847,8 @@ export class Indexer implements IndexerInterface {
         const { account, totalClaimed, totalSlashed } = logDescription.args;
         eventInfo = {
           account,
-          totalClaimed: BigInt(ethers.BigNumber.from(totalClaimed).toString()),
-          totalSlashed: BigInt(ethers.BigNumber.from(totalSlashed).toString())
+          totalClaimed: BigInt(totalClaimed.toString()),
+          totalSlashed: BigInt(totalSlashed.toString())
         };
 
         break;
@@ -858,7 +858,7 @@ export class Indexer implements IndexerInterface {
         const { value, id } = logDescription.args;
         eventInfo = {
           value,
-          id: BigInt(ethers.BigNumber.from(id).toString())
+          id: BigInt(id.toString())
         };
 
         break;
@@ -877,7 +877,7 @@ export class Indexer implements IndexerInterface {
         eventName = logDescription.name;
         const { updateThreshold } = logDescription.args;
         eventInfo = {
-          updateThreshold: BigInt(ethers.BigNumber.from(updateThreshold).toString())
+          updateThreshold: BigInt(updateThreshold.toString())
         };
 
         break;
diff --git a/packages/eden-watcher/src/resolvers.ts b/packages/eden-watcher/src/resolvers.ts
index de06a341..c72019d7 100644
--- a/packages/eden-watcher/src/resolvers.ts
+++ b/packages/eden-watcher/src/resolvers.ts
@@ -5,6 +5,8 @@
 import assert from 'assert';
 import BigInt from 'apollo-type-bigint';
 import debug from 'debug';
+import Decimal from 'decimal.js';
+import { GraphQLScalarType } from 'graphql';
 
 import { BlockHeight } from '@vulcanize/util';
 
@@ -38,6 +40,19 @@ export const createResolvers = async (indexer: Indexer, eventWatcher: EventWatch
   return {
     BigInt: new BigInt('bigInt'),
 
+    BigDecimal: new GraphQLScalarType({
+      name: 'BigDecimal',
+      description: 'BigDecimal custom scalar type',
+      parseValue (value) {
+        // value from the client
+        return new Decimal(value);
+      },
+      serialize (value: Decimal) {
+        // value sent to the client
+        return value.toFixed();
+      }
+    }),
+
     Event: {
       __resolveType: (obj: any) => {
         assert(obj.__typename);
diff --git a/packages/graph-node/src/call-handler.test.ts b/packages/graph-node/src/call-handler.test.ts
index fcc7b39b..2ac5260b 100644
--- a/packages/graph-node/src/call-handler.test.ts
+++ b/packages/graph-node/src/call-handler.test.ts
@@ -35,11 +35,16 @@ describe('call handler in mapping code', () => {
 
     sandbox.on(db, 'fromGraphEntity', async (instanceExports: any, block: Block, entity: string, entityInstance: any) => {
       const entityFields = [
-        { type: 'varchar', propertyName: 'blockHash' },
-        { type: 'integer', propertyName: 'blockNumber' },
+        { type: 'varchar', propertyName: 'id' },
         { type: 'bigint', propertyName: 'count' },
-        { type: 'varchar', propertyName: 'param1' },
-        { type: 'integer', propertyName: 'param2' }
+        { type: 'varchar', propertyName: 'paramString' },
+        { type: 'integer', propertyName: 'paramInt' },
+        { type: 'bigint', propertyName: 'paramBigInt' },
+        { type: 'boolean', propertyName: 'paramBoolean' },
+        { type: 'varchar', propertyName: 'paramBytes' },
+        { type: 'numeric', propertyName: 'paramBigDecimal' },
+        { type: 'varchar', propertyName: 'related' },
+        { type: 'varchar', propertyName: 'manyRelated' }
       ];
 
       return db.getEntityValues(instanceExports, block, entityInstance, entityFields);
@@ -69,12 +74,13 @@ describe('call handler in mapping code', () => {
 
     // Create event params data.
     const contractInterface = new utils.Interface(abi);
-    const eventFragment = contractInterface.getEvent('Test(string,uint8)');
+    const eventFragment = contractInterface.getEvent('Test(string,uint8,uint256)');
     dummyEventData.inputs = eventFragment.inputs;
 
     dummyEventData.event = {
       param1: 'abc',
-      param2: BigInt(123)
+      param2: BigInt(150),
+      param3: BigInt(564894232132154)
     };
 
     // Dummy contract address string.
diff --git a/packages/graph-node/src/loader.ts b/packages/graph-node/src/loader.ts
index f5bc03d2..b24c6c96 100644
--- a/packages/graph-node/src/loader.ts
+++ b/packages/graph-node/src/loader.ts
@@ -11,7 +11,6 @@ import {
   Contract,
   ContractInterface
 } from 'ethers';
-import Decimal from 'decimal.js';
 import JSONbig from 'json-bigint';
 import BN from 'bn.js';
 
@@ -19,7 +18,7 @@ import loader from '@vulcanize/assemblyscript/lib/loader';
 import { IndexerInterface } from '@vulcanize/util';
 
 import { TypeId } from './types';
-import { Block, fromEthereumValue, toEthereumValue, resolveEntityFieldConflicts } from './utils';
+import { Block, fromEthereumValue, toEthereumValue, resolveEntityFieldConflicts, GraphDecimal, digitsToString } from './utils';
 import { Database } from './database';
 
 const NETWORK_URL = 'http://127.0.0.1:8081';
@@ -238,12 +237,12 @@ export const instantiate = async (
         // Creating decimal x.
         const xBigDecimal = await BigDecimal.wrap(x);
         const xStringPtr = await xBigDecimal.toString();
-        const xDecimal = new Decimal(__getString(xStringPtr));
+        const xDecimal = new GraphDecimal(__getString(xStringPtr));
 
         // Create decimal y.
         const yBigDecimal = await BigDecimal.wrap(y);
         const yStringPtr = await yBigDecimal.toString();
-        const yDecimal = new Decimal(__getString(yStringPtr));
+        const yDecimal = new GraphDecimal(__getString(yStringPtr));
 
         // Performing the decimal division operation.
         const divResult = xDecimal.dividedBy(yDecimal);
@@ -267,17 +266,19 @@ export const instantiate = async (
         const expStringPtr = await expBigInt.toString();
         const exp = __getString(expStringPtr);
 
-        const decimal = new Decimal(`${digits}e${exp}`);
+        const decimal = new GraphDecimal(`${digits}e${exp}`);
         const ptr = __newString(decimal.toFixed());
 
         return ptr;
       },
       'bigDecimal.fromString': async (s: number) => {
         const string = __getString(s);
-        const decimal = new Decimal(string);
+
+        // Creating a decimal with the configured precision applied.
+        const decimal = new GraphDecimal(string).toSignificantDigits();
 
         // Convert from digits array to BigInt.
-        const digits = decimal.d.join('');
+        const digits = digitsToString(decimal.d);
         const digitsBigNumber = BigNumber.from(digits);
         const signBigNumber = BigNumber.from(decimal.s);
         const digitsStringPtr = await __newString(digitsBigNumber.mul(signBigNumber).toString());
@@ -305,7 +306,7 @@ export const instantiate = async (
         const yDecimalString = __getString(yStringPtr);
 
         // Perform the decimal sum operation.
-        const sumResult = Decimal.sum(xDecimalString, yDecimalString);
+        const sumResult = GraphDecimal.sum(xDecimalString, yDecimalString);
         const ptr = await __newString(sumResult.toString());
         const sumResultBigDecimal = await BigDecimal.fromString(ptr);
 
@@ -323,7 +324,7 @@ export const instantiate = async (
         const yDecimalString = __getString(yStringPtr);
 
         // Perform the decimal sub operation.
-        const subResult = Decimal.sub(xDecimalString, yDecimalString);
+        const subResult = GraphDecimal.sub(xDecimalString, yDecimalString);
         const ptr = await __newString(subResult.toString());
         const subResultBigDecimal = await BigDecimal.fromString(ptr);
 
@@ -341,7 +342,7 @@ export const instantiate = async (
         const yDecimalString = __getString(yStringPtr);
 
         // Perform the decimal mul operation.
-        const mulResult = Decimal.mul(xDecimalString, yDecimalString);
+        const mulResult = GraphDecimal.mul(xDecimalString, yDecimalString);
         const ptr = await __newString(mulResult.toString());
         const mulResultBigDecimal = await BigDecimal.fromString(ptr);
 
@@ -431,12 +432,12 @@ export const instantiate = async (
         // Create a decimal out of bigInt x.
         const xBigInt = await BigInt.wrap(x);
         const xStringPtr = await xBigInt.toString();
-        const xDecimal = new Decimal(__getString(xStringPtr));
+        const xDecimal = new GraphDecimal(__getString(xStringPtr));
 
         // Create decimal y.
         const yBigDecimal = await BigDecimal.wrap(y);
         const yStringPtr = await yBigDecimal.toString();
-        const yDecimal = new Decimal(__getString(yStringPtr));
+        const yDecimal = new GraphDecimal(__getString(yStringPtr));
 
         // Perform the decimal division operation.
         const divResult = xDecimal.dividedBy(yDecimal);
diff --git a/packages/graph-node/src/numbers.test.ts b/packages/graph-node/src/numbers.test.ts
index 8995e27c..6d411eda 100644
--- a/packages/graph-node/src/numbers.test.ts
+++ b/packages/graph-node/src/numbers.test.ts
@@ -90,23 +90,23 @@ describe('numbers wasm tests', () => {
     });
 
     it('should execute bigInt dividedByDecimal for positive dividend and positive divisor', async () => {
-      const ptr = await testBigIntDividedByDecimal(await __newString('2315432122132354'), await __newString('54652.65645'));
-      expect(__getString(ptr)).to.equal('42366323478.725506672');
+      const ptr = await testBigIntDividedByDecimal(await __newString('231543212213235645154'), await __newString('552.65645'));
+      expect(__getString(ptr)).to.equal('418964100053904455.7500414588484401');
     });
 
     it('should execute bigInt dividedByDecimal for negative dividend and positive divisor', async () => {
-      const ptr = await testBigIntDividedByDecimal(await __newString('-2315432122132354'), await __newString('54652.65645'));
-      expect(__getString(ptr)).to.equal('-42366323478.725506672');
+      const ptr = await testBigIntDividedByDecimal(await __newString('-231543212213235645154'), await __newString('552.65645'));
+      expect(__getString(ptr)).to.equal('-418964100053904455.7500414588484401');
     });
 
     it('should execute bigInt dividedByDecimal for positive dividend and negative divisor', async () => {
-      const ptr = await testBigIntDividedByDecimal(await __newString('2315432122132354'), await __newString('-54652.65645'));
-      expect(__getString(ptr)).to.equal('-42366323478.725506672');
+      const ptr = await testBigIntDividedByDecimal(await __newString('231543212213235645154'), await __newString('-552.65645'));
+      expect(__getString(ptr)).to.equal('-418964100053904455.7500414588484401');
     });
 
     it('should execute bigInt dividedByDecimal for negative dividend and negative divisor', async () => {
-      const ptr = await testBigIntDividedByDecimal(await __newString('-2315432122132354'), await __newString('-54652.65645'));
-      expect(__getString(ptr)).to.equal('42366323478.725506672');
+      const ptr = await testBigIntDividedByDecimal(await __newString('-231543212213235645154'), await __newString('-552.65645'));
+      expect(__getString(ptr)).to.equal('418964100053904455.7500414588484401');
     });
   });
 
@@ -121,7 +121,7 @@ describe('numbers wasm tests', () => {
     const { testBigDecimalToString, __newString, __getString } = exports;
 
     const ptr = await testBigDecimalToString(await __newString('-5032485723458348569331745849735.3343434634691214453454356561'));
-    expect(__getString(ptr)).to.equal('-5032485723458348569331745849735.3343434634691214453454356561');
+    expect(__getString(ptr)).to.equal('-5032485723458348569331745849735.334');
   });
 
   describe('should execute bigDecimal fromString API', () => {
@@ -138,7 +138,7 @@ describe('numbers wasm tests', () => {
 
     it('should get bigDecimal for numbers with decimals', async () => {
       const ptr = await testBigDecimalFromString(await __newString('-5032485723458348569331745849735.3343434634691214453454356561'));
-      expect(__getString(ptr)).to.equal('-5032485723458348569331745849735.3343434634691214453454356561');
+      expect(__getString(ptr)).to.equal('-5032485723458348569331745849735.334');
     });
   });
 
@@ -160,13 +160,13 @@ describe('numbers wasm tests', () => {
     const { testBigDecimalTimes, __getString, __newString } = exports;
 
     const ptr = await testBigDecimalTimes(await __newString('231543212.2132354'), await __newString('54652.65645'));
-    expect(__getString(ptr)).to.equal('12654451630419.398459');
+    expect(__getString(ptr)).to.equal('12654451630419.39845917833');
   });
 
   it('should execute bigDecimal dividedBy API', async () => {
     const { testBigDecimalDividedBy, __getString, __newString } = exports;
 
     const ptr = await testBigDecimalDividedBy(await __newString('231543212.2132354'), await __newString('54652.65645'));
-    expect(__getString(ptr)).to.equal('4236.6323478725506672');
+    expect(__getString(ptr)).to.equal('4236.632347872550667205491344419362');
   });
 });
diff --git a/packages/graph-node/src/utils.ts b/packages/graph-node/src/utils.ts
index 16b5f5cc..8290f546 100644
--- a/packages/graph-node/src/utils.ts
+++ b/packages/graph-node/src/utils.ts
@@ -11,6 +11,13 @@ import { TypeId, EthereumValueKind, ValueKind } from './types';
 
 const log = debug('vulcanize:utils');
 
+// Customize Decimal according the limits of IEEE-754 decimal128.
+// Reference: https://github.com/graphprotocol/graph-node/blob/v0.24.2/graph/src/data/store/scalar.rs#L42
+export const GraphDecimal = Decimal.clone({ minE: -6143, maxE: 6144, precision: 34 });
+
+// Constant used in function digitsToString.
+const LOG_BASE = 7;
+
 interface Transaction {
   hash: string;
   index: number;
@@ -436,7 +443,7 @@ const parseEntityValue = async (instanceExports: any, valuePtr: number) => {
       const bigDecimal = BigDecimal.wrap(bigDecimalPtr);
       const bigDecimalStringPtr = await bigDecimal.toString();
 
-      return new Decimal(__getString(bigDecimalStringPtr));
+      return new GraphDecimal(__getString(bigDecimalStringPtr)).toFixed();
     }
 
     case ValueKind.ARRAY: {
@@ -542,3 +549,40 @@ export const resolveEntityFieldConflicts = (entity: any): any => {
 
   return entity;
 };
+
+// Get digits in a string from an array of digit numbers (Decimal().d)
+// https://github.com/MikeMcl/decimal.js/blob/master/decimal.mjs#L2516
+export function digitsToString (d: any) {
+  let i, k, ws;
+  const indexOfLastWord = d.length - 1;
+  let str = '';
+  let w = d[0];
+
+  if (indexOfLastWord > 0) {
+    str += w;
+    for (i = 1; i < indexOfLastWord; i++) {
+      ws = d[i] + '';
+      k = LOG_BASE - ws.length;
+      if (k) str += getZeroString(k);
+      str += ws;
+    }
+
+    w = d[i];
+    ws = w + '';
+    k = LOG_BASE - ws.length;
+    if (k) str += getZeroString(k);
+  } else if (w === 0) {
+    return '0';
+  }
+
+  // Remove trailing zeros of last w.
+  for (; w % 10 === 0;) w /= 10;
+
+  return str + w;
+}
+
+function getZeroString (k: any) {
+  let zs = '';
+  for (; k--;) zs += '0';
+  return zs;
+}
diff --git a/packages/graph-node/test/contracts/Example.sol b/packages/graph-node/test/contracts/Example.sol
index ec6fd358..6f9faeaf 100644
--- a/packages/graph-node/test/contracts/Example.sol
+++ b/packages/graph-node/test/contracts/Example.sol
@@ -10,7 +10,7 @@ contract Example {
         uint128 bidAmount2;
     }
 
-    event Test(string param1, uint8 param2);
+    event Test(string param1, uint8 param2, uint256 param3);
 
     function getMethod() public view virtual returns (string memory)
     {
@@ -30,7 +30,7 @@ contract Example {
     }
 
     function emitEvent() public virtual returns (bool) {
-        emit Test('abc', 123);
+        emit Test('abc', 150, 564894232132154);
 
         return true;
     }
diff --git a/packages/graph-node/test/subgraph/example1/abis/Example1.json b/packages/graph-node/test/subgraph/example1/abis/Example1.json
index 45adb189..df17d1b9 100644
--- a/packages/graph-node/test/subgraph/example1/abis/Example1.json
+++ b/packages/graph-node/test/subgraph/example1/abis/Example1.json
@@ -13,6 +13,12 @@
         "internalType": "uint8",
         "name": "param2",
         "type": "uint8"
+      },
+      {
+        "indexed": false,
+        "internalType": "uint256",
+        "name": "param3",
+        "type": "uint256"
       }
     ],
     "name": "Test",
diff --git a/packages/graph-node/test/subgraph/example1/generated/Example1/Example1.ts b/packages/graph-node/test/subgraph/example1/generated/Example1/Example1.ts
index 5375259e..12555d96 100644
--- a/packages/graph-node/test/subgraph/example1/generated/Example1/Example1.ts
+++ b/packages/graph-node/test/subgraph/example1/generated/Example1/Example1.ts
@@ -30,6 +30,10 @@ export class Test__Params {
   get param2(): i32 {
     return this._event.parameters[1].value.toI32();
   }
+
+  get param3(): BigInt {
+    return this._event.parameters[2].value.toBigInt();
+  }
 }
 
 export class Example1__structMethodResultValue0Struct extends ethereum.Tuple {
diff --git a/packages/graph-node/test/subgraph/example1/generated/schema.ts b/packages/graph-node/test/subgraph/example1/generated/schema.ts
index 866bf97a..2c186824 100644
--- a/packages/graph-node/test/subgraph/example1/generated/schema.ts
+++ b/packages/graph-node/test/subgraph/example1/generated/schema.ts
@@ -105,6 +105,7 @@ export class Author extends Entity {
     this.set("name", Value.fromString(""));
     this.set("rating", Value.fromBigDecimal(BigDecimal.zero()));
     this.set("paramInt", Value.fromI32(0));
+    this.set("paramBigInt", Value.fromBigInt(BigInt.zero()));
     this.set("paramBytes", Value.fromBytes(Bytes.empty()));
   }
 
@@ -170,6 +171,15 @@ export class Author extends Entity {
     this.set("paramInt", Value.fromI32(value));
   }
 
+  get paramBigInt(): BigInt {
+    let value = this.get("paramBigInt");
+    return value!.toBigInt();
+  }
+
+  set paramBigInt(value: BigInt) {
+    this.set("paramBigInt", Value.fromBigInt(value));
+  }
+
   get paramBytes(): Bytes {
     let value = this.get("paramBytes");
     return value!.toBytes();
diff --git a/packages/graph-node/test/subgraph/example1/schema.graphql b/packages/graph-node/test/subgraph/example1/schema.graphql
index c36ee617..7ed5ab16 100644
--- a/packages/graph-node/test/subgraph/example1/schema.graphql
+++ b/packages/graph-node/test/subgraph/example1/schema.graphql
@@ -18,6 +18,7 @@ type Author @entity {
   name: String! # string
   rating: BigDecimal!
   paramInt: Int! # uint8
+  paramBigInt: BigInt! # uint256
   paramBytes: Bytes!
   blogs: [Blog!]! @derivedFrom(field: "author")
 }
diff --git a/packages/graph-node/test/subgraph/example1/src/mapping.ts b/packages/graph-node/test/subgraph/example1/src/mapping.ts
index 959fd2be..45a0b71a 100644
--- a/packages/graph-node/test/subgraph/example1/src/mapping.ts
+++ b/packages/graph-node/test/subgraph/example1/src/mapping.ts
@@ -10,6 +10,7 @@ export function handleTest (event: Test): void {
   log.debug('event.address: {}', [event.address.toHexString()]);
   log.debug('event.params.param1: {}', [event.params.param1]);
   log.debug('event.params.param2: {}', [event.params.param2.toString()]);
+  log.debug('event.params.param3: {}', [event.params.param3.toString()]);
   log.debug('event.block.hash: {}', [event.block.hash.toHexString()]);
   log.debug('event.block.stateRoot: {}', [event.block.stateRoot.toHexString()]);
 
@@ -32,8 +33,9 @@ export function handleTest (event: Test): void {
   // Entity fields can be set based on event parameters
   author.name = event.params.param1;
   author.paramInt = event.params.param2;
+  author.paramBigInt = event.params.param3;
   author.paramBytes = event.address;
-  author.rating = BigDecimal.fromString('4');
+  author.rating = BigDecimal.fromString('3.2132354');
 
   // Entities can be written to the store with `.save()`
   author.save();
diff --git a/packages/graph-node/test/subgraph/example1/subgraph.yaml b/packages/graph-node/test/subgraph/example1/subgraph.yaml
index 569c08de..67ec9c72 100644
--- a/packages/graph-node/test/subgraph/example1/subgraph.yaml
+++ b/packages/graph-node/test/subgraph/example1/subgraph.yaml
@@ -19,7 +19,7 @@ dataSources:
         - name: Example1
           file: ./abis/Example1.json
       eventHandlers:
-        - event: Test(string,uint8)
+        - event: Test(string,uint8,uint256)
           handler: handleTest
       blockHandlers:
         - handler: handleBlock
diff --git a/packages/graph-test-watcher/src/artifacts/Example.json b/packages/graph-test-watcher/src/artifacts/Example.json
index f48d9df3..294f2acc 100644
--- a/packages/graph-test-watcher/src/artifacts/Example.json
+++ b/packages/graph-test-watcher/src/artifacts/Example.json
@@ -14,11 +14,41 @@
           "internalType": "uint8",
           "name": "param2",
           "type": "uint8"
+        },
+        {
+          "indexed": false,
+          "internalType": "uint256",
+          "name": "param3",
+          "type": "uint256"
         }
       ],
       "name": "Test",
       "type": "event"
     },
+    {
+      "inputs": [
+        {
+          "internalType": "uint128",
+          "name": "bidAmount1",
+          "type": "uint128"
+        },
+        {
+          "internalType": "uint128",
+          "name": "bidAmount2",
+          "type": "uint128"
+        }
+      ],
+      "name": "addMethod",
+      "outputs": [
+        {
+          "internalType": "uint256",
+          "name": "",
+          "type": "uint256"
+        }
+      ],
+      "stateMutability": "pure",
+      "type": "function"
+    },
     {
       "inputs": [],
       "name": "emitEvent",
@@ -44,6 +74,42 @@
       ],
       "stateMutability": "view",
       "type": "function"
+    },
+    {
+      "inputs": [
+        {
+          "internalType": "uint128",
+          "name": "bidAmount1",
+          "type": "uint128"
+        },
+        {
+          "internalType": "uint128",
+          "name": "bidAmount2",
+          "type": "uint128"
+        }
+      ],
+      "name": "structMethod",
+      "outputs": [
+        {
+          "components": [
+            {
+              "internalType": "uint128",
+              "name": "bidAmount1",
+              "type": "uint128"
+            },
+            {
+              "internalType": "uint128",
+              "name": "bidAmount2",
+              "type": "uint128"
+            }
+          ],
+          "internalType": "struct Example.Bid",
+          "name": "",
+          "type": "tuple"
+        }
+      ],
+      "stateMutability": "pure",
+      "type": "function"
     }
   ],
   "storageLayout": {
diff --git a/packages/graph-test-watcher/src/entity/Author.ts b/packages/graph-test-watcher/src/entity/Author.ts
index 5981e743..4f1ed612 100644
--- a/packages/graph-test-watcher/src/entity/Author.ts
+++ b/packages/graph-test-watcher/src/entity/Author.ts
@@ -27,6 +27,9 @@ export class Author {
   @Column('integer')
   paramInt!: number
 
+  @Column('bigint', { transformer: bigintTransformer })
+  paramBigInt!: number
+
   @Column('varchar')
   paramBytes!: string
 
diff --git a/packages/graph-test-watcher/src/indexer.ts b/packages/graph-test-watcher/src/indexer.ts
index 7dbe2089..c447e440 100644
--- a/packages/graph-test-watcher/src/indexer.ts
+++ b/packages/graph-test-watcher/src/indexer.ts
@@ -584,10 +584,11 @@ export class Indexer implements IndexerInterface {
     switch (logDescription.name) {
       case TEST_EVENT: {
         eventName = logDescription.name;
-        const { param1, param2 } = logDescription.args;
+        const { param1, param2, param3 } = logDescription.args;
         eventInfo = {
           param1,
-          param2
+          param2,
+          param3: BigInt(param3.toString())
         };
 
         break;
diff --git a/packages/graph-test-watcher/src/resolvers.ts b/packages/graph-test-watcher/src/resolvers.ts
index fd5fd8fe..866c6b7b 100644
--- a/packages/graph-test-watcher/src/resolvers.ts
+++ b/packages/graph-test-watcher/src/resolvers.ts
@@ -5,6 +5,8 @@
 import assert from 'assert';
 import BigInt from 'apollo-type-bigint';
 import debug from 'debug';
+import Decimal from 'decimal.js';
+import { GraphQLScalarType } from 'graphql';
 
 import { ValueResult, BlockHeight } from '@vulcanize/util';
 
@@ -23,6 +25,19 @@ export const createResolvers = async (indexer: Indexer, eventWatcher: EventWatch
   return {
     BigInt: new BigInt('bigInt'),
 
+    BigDecimal: new GraphQLScalarType({
+      name: 'BigDecimal',
+      description: 'BigDecimal custom scalar type',
+      parseValue (value) {
+        // value from the client
+        return new Decimal(value);
+      },
+      serialize (value: Decimal) {
+        // value sent to the client
+        return value.toFixed();
+      }
+    }),
+
     Event: {
       __resolveType: (obj: any) => {
         assert(obj.__typename);
diff --git a/packages/graph-test-watcher/src/schema.gql b/packages/graph-test-watcher/src/schema.gql
index 99ee2d99..e96a1eb5 100644
--- a/packages/graph-test-watcher/src/schema.gql
+++ b/packages/graph-test-watcher/src/schema.gql
@@ -62,6 +62,7 @@ union Event = TestEvent
 type TestEvent {
   param1: String!
   param2: Int!
+  param3: BigInt!
 }
 
 type ResultIPLDBlock {
@@ -110,6 +111,7 @@ type Author {
   name: String!
   rating: BigDecimal!
   paramInt: Int!
+  paramBigInt: BigInt!
   paramBytes: Bytes!
   blogs: [Blog!]!
 }