diff --git a/beamer/tests/conftest.py b/beamer/tests/conftest.py
index 802bcc455..cad6edd0f 100644
--- a/beamer/tests/conftest.py
+++ b/beamer/tests/conftest.py
@@ -221,3 +221,11 @@ def resolver(contracts):
 @pytest.fixture
 def fill_manager(contracts):
     return contracts.fill_manager
+
+
+@pytest.fixture
+def fee_sub(deployer, request_manager, token):
+    fee_sub = deployer.deploy(ape.project.FeeSub, request_manager.address)
+    fee_sub.setMinimumAmount(token.address, 2)
+    token.transfer(fee_sub.address, 100)
+    return fee_sub
diff --git a/beamer/tests/contracts/test_fee_sub.py b/beamer/tests/contracts/test_fee_sub.py
new file mode 100644
index 000000000..7190f4657
--- /dev/null
+++ b/beamer/tests/contracts/test_fee_sub.py
@@ -0,0 +1,159 @@
+import ape
+from hexbytes import HexBytes
+from web3.constants import ADDRESS_ZERO
+
+from beamer.tests.agent.utils import make_address
+from beamer.tests.util import alloc_accounts, alloc_whitelisted_accounts, make_request
+
+
+def test_fee_sub(fee_sub, token, request_manager):
+    mint_amount = 5
+    sent_amount = 2
+    chain_id = ape.chain.chain_id
+    (sender, target) = alloc_accounts(2)
+
+    wrong_token_address = make_address()
+
+    total_fee = request_manager.totalFee(chain_id, token.address, sent_amount)
+    old_contract_balance = token.balanceOf(fee_sub.address)
+
+    with ape.reverts("Token not to be subsidized"):
+        fee_sub.createRequest(
+            chain_id,
+            wrong_token_address,
+            wrong_token_address,
+            target,
+            sent_amount,
+            1800,
+            sender=sender,
+        )
+
+    with ape.reverts("Transfer amount too small to be subsidized"):
+        fee_sub.createRequest(
+            chain_id, token.address, token.address, target, 1, 1800, sender=sender
+        )
+
+    token.mint(sender, mint_amount, sender=sender)
+
+    with ape.reverts("Insufficient allowance"):
+        fee_sub.createRequest(
+            chain_id, token.address, token.address, target, 2, 1800, sender=sender
+        )
+
+    token.approve(fee_sub.address, mint_amount, sender=sender)
+
+    assert token.balanceOf(sender) == mint_amount
+
+    request = fee_sub.createRequest(
+        chain_id, token.address, token.address, target, sent_amount, 1800, sender=sender
+    )
+
+    request_id = request.return_value
+
+    assert token.balanceOf(sender) == mint_amount - sent_amount  # no fee
+    assert token.balanceOf(fee_sub.address) == old_contract_balance - total_fee
+    assert (
+        request_manager.requests(request_id).sender == fee_sub.address
+    )  # sender is fee sub contract
+
+
+def test_expired_request_withdraw(fee_sub, token):
+    mint_amount = 5
+    sent_amount = 2
+    chain_id = ape.chain.chain_id
+    (sender, target) = alloc_accounts(2)
+
+    token.mint(sender, mint_amount, sender=sender)
+    token.approve(fee_sub.address, mint_amount, sender=sender)
+
+    request = fee_sub.createRequest(
+        chain_id, token.address, token.address, target, sent_amount, 1800, sender=sender
+    )
+
+    request_id = request.return_value
+
+    assert token.balanceOf(sender) == mint_amount - sent_amount
+
+    ape.chain.mine(deltatime=1800)
+
+    assert fee_sub.senders(request_id) == sender
+
+    fee_sub.withdrawExpiredRequest(request_id)
+
+    assert fee_sub.senders(request_id) == ADDRESS_ZERO
+    assert token.balanceOf(sender) == mint_amount
+
+    with ape.reverts("Already refunded to the sender"):
+        fee_sub.withdrawExpiredRequest(request_id)
+
+
+def test_invalid_withdrawal(fee_sub, token, request_manager):
+    (sender, target) = alloc_accounts(2)
+    request_id = make_request(request_manager, token, sender, target, 1)
+    with ape.reverts("Request was not created by this contract"):
+        fee_sub.withdrawExpiredRequest(request_id)
+
+
+def test_withdrawn_by_agent(fee_sub, token, request_manager, l1_messenger, claim_stake):
+    mint_amount = 5
+    sent_amount = 2
+    chain_id = ape.chain.chain_id
+    (sender, target) = alloc_accounts(2)
+    (claimer,) = alloc_whitelisted_accounts(1, [request_manager])
+
+    token.mint(sender, mint_amount, sender=sender)
+    token.approve(fee_sub.address, mint_amount, sender=sender)
+
+    request = fee_sub.createRequest(
+        chain_id, token.address, token.address, target, sent_amount, 1800, sender=sender
+    )
+
+    request_id = request.return_value
+
+    # Claim
+    fill_id = HexBytes(b"123")
+    claim_tx = request_manager.claimRequest(request_id, fill_id, sender=claimer, value=claim_stake)
+    claim_id = claim_tx.return_value
+
+    request_manager.invalidateFill(request_id, fill_id, chain_id, sender=l1_messenger)
+
+    ape.chain.mine(deltatime=1800)
+
+    request_manager.resolveRequest(request_id, fill_id, chain_id, claimer, sender=l1_messenger)
+
+    request_manager.withdraw(claim_id, sender=claimer)
+
+    with ape.reverts("Request was withdrawn by another address"):
+        fee_sub.withdrawExpiredRequest(request_id)
+
+
+def test_withdrawn_from_request_manager(fee_sub, token, request_manager):
+    mint_amount = 5
+    sent_amount = 2
+    chain_id = ape.chain.chain_id
+    (sender, target) = alloc_accounts(2)
+
+    token.mint(sender, mint_amount, sender=sender)
+    token.approve(fee_sub.address, mint_amount, sender=sender)
+
+    request = fee_sub.createRequest(
+        chain_id, token.address, token.address, target, sent_amount, 1800, sender=sender
+    )
+
+    request_id = request.return_value
+
+    ape.chain.mine(deltatime=1800)
+
+    request_manager.withdrawExpiredRequest(request_id)
+
+    fee_sub.withdrawExpiredRequest(request_id)
+
+    assert fee_sub.senders(request_id) == ADDRESS_ZERO
+
+
+def test_enable_disable_token(fee_sub, deployer, request_manager):
+    token2 = deployer.deploy(ape.project.MintableToken, request_manager.address)
+    fee_sub.setMinimumAmount(token2.address, 5)
+    assert token2.allowance(fee_sub.address, request_manager.address) == 2**256 - 1
+    fee_sub.setMinimumAmount(token2.address, 0)
+    assert token2.allowance(fee_sub.address, request_manager.address) == 0