diff --git a/web3.js/flow-typed/superstruct.js b/web3.js/flow-typed/superstruct.js
index e323ea0d2c..0384daf593 100644
--- a/web3.js/flow-typed/superstruct.js
+++ b/web3.js/flow-typed/superstruct.js
@@ -5,6 +5,7 @@ declare module 'superstruct' {
       array(schema: any): any;
       literal(schema: any): any;
       tuple(schema: any): any;
+      pick(schema: any): any;
   };
 
   declare module.exports: {
diff --git a/web3.js/module.d.ts b/web3.js/module.d.ts
index 7f3cbb6f30..db0cec087f 100644
--- a/web3.js/module.d.ts
+++ b/web3.js/module.d.ts
@@ -50,7 +50,7 @@ declare module '@solana/web3.js' {
 
   export type SignatureStatus = {
     slot: number;
-    status: SignatureSuccess | TransactionError;
+    err: TransactionError | null;
     confirmations: number | null;
   };
 
@@ -89,8 +89,8 @@ declare module '@solana/web3.js' {
         fee: number;
         preBalances: Array<number>;
         postBalances: Array<number>;
-        status?: SignatureSuccess | TransactionError;
-      };
+        err: TransactionError | null;
+      } | null;
     }>;
   };
 
@@ -126,16 +126,14 @@ declare module '@solana/web3.js' {
   ) => void;
   export type SlotChangeCallback = (slotInfo: SlotInfo) => void;
   export type SignatureResultCallback = (
-    signatureResult: SignatureSuccess | TransactionError,
+    signatureResult: SignatureResult,
     context: Context,
   ) => void;
   export type RootChangeCallback = (root: number) => void;
 
-  export type SignatureSuccess = {
-    Ok: null;
-  };
-  export type TransactionError = {
-    Err: object;
+  export type TransactionError = object;
+  export type SignatureResult = {
+    err: TransactionError | null;
   };
 
   export type Inflation = {
diff --git a/web3.js/module.flow.js b/web3.js/module.flow.js
index cb7e83aed4..7a74c17455 100644
--- a/web3.js/module.flow.js
+++ b/web3.js/module.flow.js
@@ -19,7 +19,7 @@ declare module '@solana/web3.js' {
     constructor(
       value: number | string | Buffer | Uint8Array | Array<number>,
     ): PublicKey;
-    static isPublicKey(o: Object): boolean;
+    static isPublicKey(o: {}): boolean;
     static createWithSeed(
       fromPublicKey: PublicKey,
       seed: string,
@@ -63,7 +63,7 @@ declare module '@solana/web3.js' {
 
   declare export type SignatureStatus = {
     slot: number,
-    status: SignatureSuccess | TransactionError,
+    err: TransactionError | null,
     confirmations: number | null,
   };
 
@@ -102,8 +102,8 @@ declare module '@solana/web3.js' {
         fee: number,
         preBalances: Array<number>,
         postBalances: Array<number>,
-        status: SignatureSuccess | TransactionError | null,
-      },
+        err: TransactionError | null,
+      } | null,
     }>,
   };
 
@@ -139,16 +139,14 @@ declare module '@solana/web3.js' {
   ) => void;
   declare type SlotChangeCallback = (slotInfo: SlotInfo) => void;
   declare type SignatureResultCallback = (
-    signatureResult: SignatureSuccess | TransactionError,
+    signatureResult: SignatureResult,
     context: Context,
   ) => void;
   declare type RootChangeCallback = (root: number) => void;
 
-  declare export type SignatureSuccess = {|
-    Ok: null,
-  |};
-  declare export type TransactionError = {|
-    Err: Object,
+  declare export type TransactionError = {};
+  declare export type SignatureResult = {|
+    err: TransactionError | null,
   |};
 
   declare export type Inflation = {
@@ -331,10 +329,7 @@ declare module '@solana/web3.js' {
     layout: typeof BufferLayout,
   |};
 
-  declare export function encodeData(
-    type: InstructionType,
-    fields: Object,
-  ): Buffer;
+  declare export function encodeData(type: InstructionType, fields: {}): Buffer;
 
   // === src/transaction.js ===
   declare export type TransactionSignature = string;
diff --git a/web3.js/src/connection.js b/web3.js/src/connection.js
index 8dac8c64f9..d4d0302375 100644
--- a/web3.js/src/connection.js
+++ b/web3.js/src/connection.js
@@ -203,13 +203,15 @@ const GetEpochScheduleResult = struct({
   firstNormalSlot: 'number',
 });
 
+/**
+ * Transaction error or null
+ */
+const TransactionErrorResult = struct.union(['null', 'object']);
+
 /**
  * Signature status for a transaction
  */
-const SignatureStatusResult = struct.union([
-  struct({Ok: 'null'}),
-  struct({Err: 'object'}),
-]);
+const SignatureStatusResult = struct({err: TransactionErrorResult});
 
 /**
  * Version info for a node
@@ -241,8 +243,8 @@ type ConfirmedBlock = {
       fee: number,
       preBalances: Array<number>,
       postBalances: Array<number>,
-      status?: SignatureSuccess | TransactionError,
-    },
+      err: {} | null,
+    } | null,
   }>,
   rewards: Array<{
     pubkey: string,
@@ -483,10 +485,10 @@ const GetSignatureStatusesRpcResult = jsonRpcResultAndContext(
   struct.array([
     struct.union([
       'null',
-      struct({
+      struct.pick({
         slot: 'number',
         confirmations: struct.union(['number', 'null']),
-        status: SignatureStatusResult,
+        err: TransactionErrorResult,
       }),
     ]),
   ]),
@@ -543,8 +545,8 @@ export const GetConfirmedBlockRpcResult = jsonRpcResult(
           }),
           meta: struct.union([
             'null',
-            struct({
-              status: struct.union(['null', SignatureStatusResult]),
+            struct.pick({
+              err: TransactionErrorResult,
               fee: 'number',
               preBalances: struct.array(['number']),
               postBalances: struct.array(['number']),
@@ -685,7 +687,7 @@ type SlotSubscriptionInfo = {
  * Callback function for signature notifications
  */
 export type SignatureResultCallback = (
-  signatureResult: SignatureSuccess | TransactionError,
+  signatureResult: SignatureResult,
   context: Context,
 ) => void;
 
@@ -712,22 +714,20 @@ type RootSubscriptionInfo = {
 };
 
 /**
- * Signature status: Success
+ * Signature result
  *
- * @typedef {Object} SignatureSuccess
+ * @typedef {Object} SignatureResult
  */
-export type SignatureSuccess = {|
-  Ok: null,
+export type SignatureResult = {|
+  err: TransactionError | null,
 |};
 
 /**
- * Signature status: TransactionError
+ * Transaction error
  *
  * @typedef {Object} TransactionError
  */
-export type TransactionError = {|
-  Err: Object,
-|};
+export type TransactionError = {};
 
 /**
  * Signature status
@@ -735,12 +735,12 @@ export type TransactionError = {|
  * @typedef {Object} SignatureStatus
  * @property {number} slot when the transaction was processed
  * @property {number | null} confirmations the number of blocks that have been confirmed and voted on in the fork containing `slot` (TODO)
- * @property {SignatureStatus | TransactionError} status success or error
+ * @property {TransactionError | null} err error, if any
  */
 export type SignatureStatus = {
   slot: number,
   confirmations: number | null,
-  status: SignatureSuccess | TransactionError,
+  err: TransactionError | null,
 };
 
 /**
diff --git a/web3.js/src/util/send-and-confirm-raw-transaction.js b/web3.js/src/util/send-and-confirm-raw-transaction.js
index be3b6d28d0..3d980dc6f9 100644
--- a/web3.js/src/util/send-and-confirm-raw-transaction.js
+++ b/web3.js/src/util/send-and-confirm-raw-transaction.js
@@ -39,7 +39,7 @@ export async function sendAndConfirmRawTransaction(
     }
   }
 
-  if (status && status.status && 'Ok' in status.status) {
+  if (status && !status.err) {
     return signature;
   }
 
diff --git a/web3.js/src/util/send-and-confirm-transaction.js b/web3.js/src/util/send-and-confirm-transaction.js
index aebf6996e8..b0ee04b70e 100644
--- a/web3.js/src/util/send-and-confirm-transaction.js
+++ b/web3.js/src/util/send-and-confirm-transaction.js
@@ -66,9 +66,16 @@ async function _sendAndConfirmTransaction(
       await sleep((500 * DEFAULT_TICKS_PER_SLOT) / NUM_TICKS_PER_SECOND);
     }
 
-    if (status && 'Ok' in status.status) {
-      break;
+    if (status) {
+      if (!status.err) {
+        break;
+      } else if (!('AccountInUse' in status.err)) {
+        throw new Error(
+          `Transaction ${signature} failed (${JSON.stringify(status)})`,
+        );
+      }
     }
+
     if (--sendRetries <= 0) {
       const duration = (Date.now() - start) / 1000;
       throw new Error(
@@ -78,12 +85,6 @@ async function _sendAndConfirmTransaction(
       );
     }
 
-    if (status && status.status.Err && !('AccountInUse' in status.status.Err)) {
-      throw new Error(
-        `Transaction ${signature} failed (${JSON.stringify(status)})`,
-      );
-    }
-
     // Retry in 0..100ms to try to avoid another AccountInUse collision
     await sleep(Math.random() * 100);
   }
diff --git a/web3.js/test/connection.test.js b/web3.js/test/connection.test.js
index 2a7f8aeb5a..b6c3080cc2 100644
--- a/web3.js/test/connection.test.js
+++ b/web3.js/test/connection.test.js
@@ -117,6 +117,7 @@ test('get program accounts', async () => {
             slot: 0,
             confirmations: 11,
             status: {Ok: null},
+            err: null,
           },
         ],
       },
@@ -161,6 +162,7 @@ test('get program accounts', async () => {
             slot: 0,
             confirmations: 11,
             status: {Ok: null},
+            err: null,
           },
         ],
       },
@@ -627,6 +629,7 @@ test('get confirmed block', async () => {
               postBalances: [499260347380, 15298080, 1, 1, 1],
               preBalances: [499260357380, 15298080, 1, 1, 1],
               status: {Ok: null},
+              err: null,
             },
             transaction: {
               message: {
@@ -906,6 +909,7 @@ test('request airdrop - max commitment', async () => {
             slot: 0,
             confirmations: null,
             status: {Ok: null},
+            err: null,
           },
         ],
       },
@@ -1100,6 +1104,7 @@ test('transaction', async () => {
             slot: 0,
             confirmations: 11,
             status: {Ok: null},
+            err: null,
           },
         ],
       },
@@ -1118,7 +1123,7 @@ test('transaction', async () => {
     return;
   }
 
-  expect(response.status).toEqual({Ok: null});
+  expect(response.err).toBeNull();
   expect(response.slot).toBeGreaterThanOrEqual(0);
   expect(responseConfirmations).toBeGreaterThan(0);
 
@@ -1147,6 +1152,7 @@ test('transaction', async () => {
             slot: 0,
             confirmations: 11,
             status: {Ok: null},
+            err: null,
           },
           null,
         ],
@@ -1168,7 +1174,7 @@ test('transaction', async () => {
   }
 
   expect(firstResponse.slot).toBeGreaterThanOrEqual(response.slot);
-  expect(firstResponse.status).toEqual(response.status);
+  expect(firstResponse.err).toEqual(response.err);
 
   if (typeof firstResponse.confirmations !== 'number') {
     expect(typeof firstResponse.confirmations).toEqual('number');
@@ -1279,7 +1285,7 @@ test('multi-instruction transaction', async () => {
   const response = (await connection.getSignatureStatus(signature)).value;
   if (response !== null) {
     expect(typeof response.slot).toEqual('number');
-    expect(response.status).toEqual({Ok: null});
+    expect(response.err).toBeNull();
   } else {
     expect(response).not.toBeNull();
   }
diff --git a/web3.js/test/get-confirmed-block.test.js b/web3.js/test/get-confirmed-block.test.js
index 60c890e0a9..4031476b8b 100644
--- a/web3.js/test/get-confirmed-block.test.js
+++ b/web3.js/test/get-confirmed-block.test.js
@@ -39,7 +39,8 @@ test('verify getConfirmedBlock', () => {
           fee: 0,
           preBalances: [100000, 100000, 1, 1, 1],
           postBalances: [99877, 100123, 1, 1, 1],
-          status: {Ok: 'null'},
+          status: {Ok: null},
+          err: null,
         },
       },
       {
@@ -48,7 +49,8 @@ test('verify getConfirmedBlock', () => {
           fee: 0,
           preBalances: [100000, 100000, 1, 1, 1],
           postBalances: [99544, 100456, 1, 1, 1],
-          status: {Ok: 'null'},
+          status: {Ok: null},
+          err: null,
         },
       },
     ],
diff --git a/web3.js/test/transaction-payer.test.js b/web3.js/test/transaction-payer.test.js
index 8bf5037d6d..629d87e79c 100644
--- a/web3.js/test/transaction-payer.test.js
+++ b/web3.js/test/transaction-payer.test.js
@@ -165,6 +165,7 @@ test('transaction-payer', async () => {
             slot: 0,
             confirmations: 11,
             status: {Ok: null},
+            err: null,
           },
         ],
       },
@@ -173,7 +174,7 @@ test('transaction-payer', async () => {
   const {value} = await connection.getSignatureStatus(signature);
   if (value !== null) {
     expect(typeof value.slot).toEqual('number');
-    expect(value.status).toEqual({Ok: null});
+    expect(value.err).toBeNull();
   } else {
     expect(value).not.toBeNull();
   }