diff --git a/packages/light.js/src/rpc/other/makeContract.ts b/packages/light.js/src/rpc/other/makeContract.ts
index 8c718285..55bf8bdd 100644
--- a/packages/light.js/src/rpc/other/makeContract.ts
+++ b/packages/light.js/src/rpc/other/makeContract.ts
@@ -45,14 +45,13 @@ const getContract = memoizee(
  * @ignore
  * @param address - The contract address.
  * @param abiJson - The contract abi.
- * @param passphrase - Passphrase of the account creating the contract
  * @param api - The api Object.
  * @return - An object whose keys are all the functions of the
  * contract, and each function returns an Observable which will fire when the
  * function resolves.
  */
 const makeContractWithApi = memoizee(
-  (address: Address, abiJson: any[], passphrase: string, api: any) => {
+  (address: Address, abiJson: any[], api: any) => {
     const abi = new Abi(abiJson); // use types from @parity/abi
 
     // Variable result will hold the final object to return
@@ -90,6 +89,8 @@ const makeContractWithApi = memoizee(
             ]
           })({ provider: api.provider })(...args);
         } else {
+          const { estimate, passphrase, ...txFields } = options;
+
           return post$({
             to: address,
             data: abiEncode(
@@ -97,8 +98,8 @@ const makeContractWithApi = memoizee(
               method.inputs.map(({ kind: { type } }: any) => type), // TODO Use @parity/api types
               args
             ),
-            ...options
-          }, passphrase);
+            ...txFields
+          }, { estimate, passphrase });
         }
       };
     });
@@ -112,7 +113,6 @@ const makeContractWithApi = memoizee(
  *
  * @param address - The contract address.
  * @param abiJson - The contract abi.
- * @param passphrase - Passphrase of the account creating the contract
  * @param options - The options to pass in when creating the contract.
  * @return - An object whose keys are all the functions of the
  * contract, and each function return an Observable which will fire when the
@@ -121,11 +121,10 @@ const makeContractWithApi = memoizee(
 export const makeContract = (
   address: Address,
   abiJson: any[],
-  passphrase: string,
   options: { provider?: any } = {}
 ) => {
   const { provider } = options;
   const api = provider ? createApiFromProvider(provider) : getApi();
 
-  return makeContractWithApi(address, abiJson, passphrase, api);
+  return makeContractWithApi(address, abiJson, api);
 };
diff --git a/packages/light.js/src/rpc/other/post.ts b/packages/light.js/src/rpc/other/post.ts
index 78711874..dbd51855 100644
--- a/packages/light.js/src/rpc/other/post.ts
+++ b/packages/light.js/src/rpc/other/post.ts
@@ -13,6 +13,7 @@ import { RpcObservableOptions, Tx, TxStatus } from '../../types';
 
 interface PostOptions extends RpcObservableOptions {
   estimate?: boolean;
+  passphrase: String;
 }
 
 function getTransactionReceipt (transactionHash: string, api: any) {
@@ -42,12 +43,16 @@ function getTransactionReceipt (transactionHash: string, api: any) {
  * the transaction.
  *
  * @param tx - Transaction object
- * @param passphrase - Passphrase of the account
- * @param options? - Options to pass to the {@link RpcObservable}.
- * @return - The status of the transaction.
+ * @param options - Options to pass to the {@link RpcObservable}.
+ * @param options.passphrase - Passphrase of the account
+ * @return - The status of the transaction: (estimated), signed, sent, confirmed
  */
-export function post$ (tx: Tx, passphrase: string, options: PostOptions = {}) {
-  const { estimate, provider } = options;
+export function post$ (tx: Tx, options: PostOptions) {
+  const { estimate, passphrase, provider } = options;
+  if (!passphrase) {
+    throw new Error('The passphrase is missing from the options');
+  }
+
   const api = provider ? createApiFromProvider(provider) : getApi();
 
   const source$ = Observable.create(async (observer: Observer<TxStatus>) => {
@@ -80,9 +85,9 @@ export function post$ (tx: Tx, passphrase: string, options: PostOptions = {}) {
  *
  * @param rawTx - Raw transaction
  * @param options? - Options to pass to the {@link RpcObservable}.
- * @return - The status of the transaction.
+ * @return - The status of the transaction: sent, confirmed
  */
-export function postRaw$ (rawTx: string, options: PostOptions = {}) {
+export function postRaw$ (rawTx: string, options: RpcObservableOptions = {}) {
   const { provider } = options;
   const api = provider ? createApiFromProvider(provider) : getApi();