diff --git a/packages/stargate/package.json b/packages/stargate/package.json
index 5b69f12a..58f477c7 100644
--- a/packages/stargate/package.json
+++ b/packages/stargate/package.json
@@ -45,6 +45,7 @@
     "postdefine-proto": "prettier --write \"src/codec/generated/codecimpl.*\""
   },
   "dependencies": {
+    "@confio/ics23": "^0.6.0",
     "@cosmjs/encoding": "^0.22.2",
     "@cosmjs/launchpad": "^0.22.2",
     "@cosmjs/math": "^0.22.2",
diff --git a/packages/stargate/src/queries/queryclient.ts b/packages/stargate/src/queries/queryclient.ts
index 460e2221..8f8759f7 100644
--- a/packages/stargate/src/queries/queryclient.ts
+++ b/packages/stargate/src/queries/queryclient.ts
@@ -1,8 +1,44 @@
 /* eslint-disable no-dupe-class-members, @typescript-eslint/ban-types, @typescript-eslint/naming-convention */
-import { toHex, fromAscii } from "@cosmjs/encoding";
+import { ics23, verifyExistence } from "@confio/ics23";
+import { fromAscii, toHex } from "@cosmjs/encoding";
 import { Client as TendermintClient } from "@cosmjs/tendermint-rpc";
 import { arrayContentEquals, assert, isNonNullObject } from "@cosmjs/utils";
 
+// TODO: import these from @confio/ics23 when exported
+export const IavlSpec: ics23.IProofSpec = {
+  leafSpec: {
+    prefix: Uint8Array.from([0]),
+    hash: ics23.HashOp.SHA256,
+    prehashValue: ics23.HashOp.SHA256,
+    prehashKey: ics23.HashOp.NO_HASH,
+    length: ics23.LengthOp.VAR_PROTO,
+  },
+  innerSpec: {
+    childOrder: [0, 1],
+    minPrefixLength: 4,
+    maxPrefixLength: 12,
+    childSize: 33,
+    hash: ics23.HashOp.SHA256,
+  },
+};
+
+export const TendermintSpec: ics23.IProofSpec = {
+  leafSpec: {
+    prefix: Uint8Array.from([0]),
+    hash: ics23.HashOp.SHA256,
+    prehashValue: ics23.HashOp.SHA256,
+    prehashKey: ics23.HashOp.NO_HASH,
+    length: ics23.LengthOp.VAR_PROTO,
+  },
+  innerSpec: {
+    childOrder: [0, 1],
+    minPrefixLength: 1,
+    maxPrefixLength: 1,
+    childSize: 32,
+    hash: ics23.HashOp.SHA256,
+  },
+};
+
 type QueryExtensionSetup<P> = (base: QueryClient) => P;
 
 export class QueryClient {
@@ -166,25 +202,46 @@ export class QueryClient {
       throw new Error(`Expected 2 proof ops, got ${response.proof.ops.length}. Are you using stargate?`);
     }
 
-    const subProof = response.proof.ops[0];
-    if (subProof.type !== "ics23:iavl") {
-      throw new Error(`Sub-proof expected to be ics23:iavl, got "${subProof.type}`);
+    const subOp = response.proof.ops[0];
+    if (subOp.type !== "ics23:iavl") {
+      throw new Error(`Sub-proof expected to be ics23:iavl, got "${subOp.type}`);
     }
-    if (!arrayContentEquals(key, subProof.key)) {
-      throw new Error(`Proven key different than queried key.\nQuery: ${toHex(key)}\nProven: ${toHex(subProof.key)}`);
-    }
-    console.log(`Proof: ${toHex(subProof.data)}`);
-
-    const storeProof = response.proof.ops[1];
-    if (storeProof.type !== "ics23:simple") {
-      throw new Error(`Store-proof expected to be ics23:simple, got "${storeProof.type}`);
-    }
-    if (store !== fromAscii(storeProof.key)) {
-      throw new Error(`Proven store "${store}" different than queried store ${fromAscii(storeProof.key)}`);
+    if (!arrayContentEquals(key, subOp.key)) {
+      throw new Error(
+        `Proven key different than queried key.\nQuery: ${toHex(key)}\nProven: ${toHex(subOp.key)}`,
+      );
     }
 
-    // TODO: implement proof verification
-    // https://github.com/CosmWasm/cosmjs/issues/347
+    const storeOp = response.proof.ops[1];
+    if (storeOp.type !== "ics23:simple") {
+      throw new Error(`Store-proof expected to be ics23:simple, got "${storeOp.type}`);
+    }
+    if (store !== fromAscii(storeOp.key)) {
+      throw new Error(`Proven store "${store}" different than queried store ${fromAscii(storeOp.key)}`);
+    }
+
+    assert(response.height);
+    assert(response.height > 0);
+
+    // parse proofs
+    const subProof = ics23.CommitmentProof.decode(subOp.data);
+    assert(subProof.exist);
+    assert(subProof.exist.value);
+
+    const storeProof = ics23.CommitmentProof.decode(storeOp.data);
+    assert(storeProof.exist);
+    assert(storeProof.exist.value);
+
+    // the subproof must map the desired key to the "value" of the storeProof
+    verifyExistence(subProof.exist, IavlSpec, storeProof.exist.value, key, response.value);
+
+    // the storeproof must may it's declared value (root of subProof) to the appHash
+    // TODO
+    // // get the header for height + 1
+    // await sleep(5000); // TODO: we can do better
+    // // TODO: why don't we expose the header query, just height?
+    // const header = await this.tmClient.block(response.height+1);
+    // verifyExistence(storeProof.exist, TendermintSpec, header.block.header.appHash, toAscii(store), storeProof.exist.value!);
 
     return response.value;
   }
diff --git a/packages/stargate/types/queries/queryclient.d.ts b/packages/stargate/types/queries/queryclient.d.ts
index c00db57b..a0518931 100644
--- a/packages/stargate/types/queries/queryclient.d.ts
+++ b/packages/stargate/types/queries/queryclient.d.ts
@@ -1,3 +1,4 @@
+import { ics23 } from "@confio/ics23";
 import { Client as TendermintClient } from "@cosmjs/tendermint-rpc";
 declare type QueryExtensionSetup<P> = (base: QueryClient) => P;
 export declare class QueryClient {
@@ -106,4 +107,6 @@ export declare class QueryClient {
   queryVerified(store: string, key: Uint8Array): Promise<Uint8Array>;
   queryUnverified(path: string, request: Uint8Array): Promise<Uint8Array>;
 }
+export declare const IavlSpec: ics23.IProofSpec;
+export declare const TendermintSpec: ics23.IProofSpec;
 export {};
diff --git a/packages/tendermint-rpc/src/v0-33/responses.ts b/packages/tendermint-rpc/src/v0-33/responses.ts
index ae08ee0e..3e785ac1 100644
--- a/packages/tendermint-rpc/src/v0-33/responses.ts
+++ b/packages/tendermint-rpc/src/v0-33/responses.ts
@@ -25,7 +25,6 @@ import * as responses from "../responses";
 import { SubscriptionEvent } from "../rpcclients";
 import { IpPortString, TxBytes, TxHash, ValidatorPubkey, ValidatorSignature } from "../types";
 import { hashTx } from "./hasher";
-import { isArgon2idOptions } from "@cosmjs/crypto";
 
 interface AbciInfoResult {
   readonly response: RpcAbciInfoResponse;
diff --git a/yarn.lock b/yarn.lock
index 6b81d06a..3220ddc9 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -177,6 +177,15 @@
     lodash "^4.17.13"
     to-fast-properties "^2.0.0"
 
+"@confio/ics23@^0.6.0":
+  version "0.6.0"
+  resolved "https://registry.yarnpkg.com/@confio/ics23/-/ics23-0.6.0.tgz#8c3e6508159bdbee02b12beeee9b369ea68ef6ba"
+  integrity sha512-P/NcAO3pz7xXg4cpwaKRUIN4PuOOxwY94n7WD+wod7UG5YlMLzb8Upv6nZo9/brnKXW4gXB2DccLTtV0Um1Wvw==
+  dependencies:
+    protobufjs "^6.8.8"
+    ripemd160 "^2.0.2"
+    sha.js "^2.4.11"
+
 "@evocateur/libnpmaccess@^3.1.2":
   version "3.1.2"
   resolved "https://registry.yarnpkg.com/@evocateur/libnpmaccess/-/libnpmaccess-3.1.2.tgz#ecf7f6ce6b004e9f942b098d92200be4a4b1c845"
@@ -6764,6 +6773,25 @@ proto-list@~1.2.1:
   resolved "https://registry.yarnpkg.com/proto-list/-/proto-list-1.2.4.tgz#212d5bfe1318306a420f6402b8e26ff39647a849"
   integrity sha1-IS1b/hMYMGpCD2QCuOJv85ZHqEk=
 
+protobufjs@^6.8.8:
+  version "6.10.1"
+  resolved "https://registry.yarnpkg.com/protobufjs/-/protobufjs-6.10.1.tgz#e6a484dd8f04b29629e9053344e3970cccf13cd2"
+  integrity sha512-pb8kTchL+1Ceg4lFd5XUpK8PdWacbvV5SK2ULH2ebrYtl4GjJmS24m6CKME67jzV53tbJxHlnNOSqQHbTsR9JQ==
+  dependencies:
+    "@protobufjs/aspromise" "^1.1.2"
+    "@protobufjs/base64" "^1.1.2"
+    "@protobufjs/codegen" "^2.0.4"
+    "@protobufjs/eventemitter" "^1.1.0"
+    "@protobufjs/fetch" "^1.1.0"
+    "@protobufjs/float" "^1.0.2"
+    "@protobufjs/inquire" "^1.1.0"
+    "@protobufjs/path" "^1.1.2"
+    "@protobufjs/pool" "^1.1.0"
+    "@protobufjs/utf8" "^1.1.0"
+    "@types/long" "^4.0.1"
+    "@types/node" "^13.7.0"
+    long "^4.0.0"
+
 protobufjs@~6.10.0:
   version "6.10.0"
   resolved "https://registry.yarnpkg.com/protobufjs/-/protobufjs-6.10.0.tgz#b0698a2a91fc597e2dc625dcf3539ece9675c8fd"