diff --git a/packages/ui-api/src/types.ts b/packages/ui-api/src/types.ts
index 647bc898b2..c13d39f0ce 100644
--- a/packages/ui-api/src/types.ts
+++ b/packages/ui-api/src/types.ts
@@ -5,6 +5,10 @@
 import { SubmittableExtrinsicFunction } from '@polkadot/api/promise/types';
 import ApiPromise from '@polkadot/api/promise';
 
+// helpers for HOC props
+export type Omit<T, K> = Pick<T, Exclude<keyof T, K>>;
+export type Subtract<T, K> = Omit<T, keyof K>;
+
 export type BareProps = {
   className?: string,
   style?: { [index: string]: any }
diff --git a/packages/ui-api/src/with/api.tsx b/packages/ui-api/src/with/api.tsx
index b14a8df72e..d465e53a44 100644
--- a/packages/ui-api/src/with/api.tsx
+++ b/packages/ui-api/src/with/api.tsx
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
-import { ApiProps } from '../types';
+import { ApiProps, Subtract } from '../types';
 import { DefaultProps } from './types';
 
 import React from 'react';
@@ -11,7 +11,7 @@ import { assert } from '@polkadot/util';
 import { ApiConsumer } from '../ApiContext';
 
 export default function withApi <T, P extends ApiProps> (Inner: React.ComponentType<P>, defaultProps: DefaultProps<T> = {}): React.ComponentType<any> {
-  return class WithApi extends React.PureComponent<any> {
+  return class WithApi extends React.PureComponent<Subtract<P, ApiProps>> {
     constructor (props: any) {
       super(props);
 
diff --git a/packages/ui-api/src/with/call.tsx b/packages/ui-api/src/with/call.tsx
index fffb008bec..ad255eb860 100644
--- a/packages/ui-api/src/with/call.tsx
+++ b/packages/ui-api/src/with/call.tsx
@@ -2,8 +2,6 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
-// TODO: Lots of duplicated code between this and withObservable, surely there is a better way of doing this?
-
 import { ApiProps, RxProps } from '../types';
 import { HOC, Options } from './types';
 
@@ -26,20 +24,16 @@ type State<T> = RxProps<T> & {
   timerId: number
 };
 
-type Props = ApiProps & {};
-
 const NOOP = () => {
   // ignore
 };
 
-// FIXME proper types for attributes
-
-export default function withCall<T, P> (endpoint: string, { at, atProp, rxChange, params = [], paramProp = 'params', propName, transform = echoTransform }: Options<T> = {}): HOC<T> {
+export default function withCall<T, P extends ApiProps> (endpoint: string, { at, atProp, rxChange, params = [], paramProp = 'params', propName, transform = echoTransform }: Options<T> = {}): HOC<T> {
   return (Inner: React.ComponentType<ApiProps>): React.ComponentType<any> => {
-    class WithPromise extends React.Component<Props, State<T>> {
+    class WithPromise extends React.Component<P, State<T>> {
       state: State<T>;
 
-      constructor (props: Props) {
+      constructor (props: P) {
         super(props);
 
         const [area, section, method] = endpoint.split('.');