diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index b655f8fa..cd66d4d1 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -232,6 +232,15 @@ jobs:
       - name: Init public submodules
         run: git submodule update --init contracts/lib/forge-std contracts/lib/openzeppelin-contracts contracts/lib/openzeppelin-contracts-upgradeable
 
+      - name: Setup Node.js
+        uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
+        with:
+          node-version: 22
+          cache: npm
+
+      - name: Install Node dependencies
+        run: npm ci
+
       - name: Read Foundry version
         id: foundry-version
         run: echo "version=$(cat .foundry-version)" >> $GITHUB_OUTPUT
@@ -244,6 +253,9 @@ jobs:
       - name: Run Foundry tests
         run: forge test -vvv --gas-report
 
+      - name: Run Hardhat unit tests
+        run: make test-unit-hardhat
+
   # ---------------------------------------------------------------------------
   # Docker Images
   # ---------------------------------------------------------------------------
diff --git a/scripts/genesis/genesis.ts b/scripts/genesis/genesis.ts
index d5444923..2c81f052 100644
--- a/scripts/genesis/genesis.ts
+++ b/scripts/genesis/genesis.ts
@@ -176,11 +176,14 @@ export const buildGenesis = async (ctx: BuilderContext, config: GenesisConfig) =
   } = parsed
 
   const allocs: Record<Address, GenesisAccountAlloc> = {}
+  const allocatedAddresses = new Set<string>()
   const insert = ([account, alloc]: [string, GenesisAccountAlloc]) => {
-    if (account in allocs) {
+    const normalizedAddress = account.toLowerCase()
+    if (allocatedAddresses.has(normalizedAddress)) {
       throw new Error(`Duplicate account: ${account}`)
     }
     allocs[schemaAddress.parse(account)] = alloc
+    allocatedAddresses.add(normalizedAddress)
   }
 
   Object.entries(await buildNativeFiatTokenGenesisAllocs(ctx, nativeFiatToken)).forEach(insert)
diff --git a/tests/unit/genesis-account-collisions.test.ts b/tests/unit/genesis-account-collisions.test.ts
new file mode 100644
index 00000000..8bfb198a
--- /dev/null
+++ b/tests/unit/genesis-account-collisions.test.ts
@@ -0,0 +1,136 @@
+// Copyright 2026 Circle Internet Group, Inc. All rights reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+
+import { strict as assert } from 'node:assert'
+import { Address, fromHex, getAddress, toHex } from 'viem'
+import { nativeCoinAutorityAddress } from '../../scripts/genesis/addresses'
+import { BuilderContext, ContractLoader } from '../../scripts/genesis/context'
+import { buildGenesis, externalContracts, GenesisConfig } from '../../scripts/genesis/genesis'
+import { slotIndex } from '../../scripts/genesis/types'
+
+const admin = '0x1111111111111111111111111111111111111111'
+const operator = '0x2222222222222222222222222222222222222222'
+const account = '0xabcdefabcdefabcdefabcdefabcdefabcdefabcd'
+const checksumAccount = getAddress(account)
+const otherAccount = '0xabcdefabcdefabcdefabcdefabcdefabcdefabce'
+const implementationAddress = '0xabcdef0000000000000000000000000000000001'
+
+function context(): BuilderContext {
+  return {
+    network: 'localdev',
+    chainId: 1337,
+    projectRoot: process.cwd(),
+    // Only artifact loading is stubbed; all genesis allocation builders run normally.
+    contractLoader: new ContractLoader(
+      {
+        SignatureChecker: { address: toHex(0x1001n, { size: 20 }), code: '0x00' },
+        NativeFiatTokenV2_2: { address: implementationAddress, code: '0x00' },
+        FiatTokenProxy: { address: toHex(0x1003n, { size: 20 }), code: '0x00' },
+        ProtocolConfig: { address: toHex(0x1004n, { size: 20 }), code: '0x00' },
+        ValidatorRegistry: { address: toHex(0x1005n, { size: 20 }), code: '0x00' },
+        PermissionedValidatorManager: { address: toHex(0x1006n, { size: 20 }), code: '0x00' },
+        AdminUpgradeableProxy: { address: toHex(0x1007n, { size: 20 }), code: '0x00' },
+      },
+      {},
+    ),
+  }
+}
+
+function config(prefund: Array<{ address: Address; balance: bigint }>): GenesisConfig {
+  return {
+    timestamp: 0n,
+    coinbase: operator,
+    prefund,
+    NativeFiatToken: {
+      proxy: { admin },
+      owner: operator,
+      pauser: operator,
+      blacklister: operator,
+      masterMinter: operator,
+      rescuer: operator,
+      minters: [],
+    },
+    ProtocolConfig: {
+      proxy: { admin },
+      owner: operator,
+      controller: operator,
+      pauser: operator,
+      feeParams: {
+        alpha: 1n,
+        kRate: 1n,
+        inverseElasticityMultiplier: 1n,
+        minBaseFee: 0n,
+        maxBaseFee: 1_000_000n,
+        blockGasLimit: 30_000_000n,
+      },
+    },
+    ValidatorManager: {
+      proxy: { admin },
+      validators: [
+        {
+          publicKey: `0x${'11'.repeat(32)}`,
+          votingPower: 20n,
+          controllers: [{ address: operator, votingPowerLimit: 100n }],
+        },
+      ],
+      PermissionedValidatorManager: {
+        proxy: { admin },
+        owner: operator,
+        pauser: operator,
+        validatorRegisterers: [operator],
+      },
+    },
+    ...Object.fromEntries(externalContracts.map((name) => [name, false])),
+  }
+}
+
+describe('genesis account collisions', () => {
+  for (const addresses of [
+    [account, checksumAccount],
+    [checksumAccount, account],
+    [account, account],
+  ] as const) {
+    it(`rejects duplicate prefunds ${addresses.join(' / ')}`, async () => {
+      await assert.rejects(buildGenesis(context(), config(addresses.map((address) => ({ address, balance: 10n })))), {
+        message: `Duplicate account: ${addresses[1]}`,
+      })
+    })
+  }
+
+  it('rejects a prefund alias of a contract implementation', async () => {
+    const address = getAddress(implementationAddress)
+    assert.notEqual(address, implementationAddress)
+    await assert.rejects(buildGenesis(context(), config([{ address, balance: 10n }])), {
+      message: `Duplicate account: ${address}`,
+    })
+  })
+
+  it('rejects a prefund alias of a reserved precompile', async () => {
+    const address = '0x180000000000000000000000000000000000000A'
+    await assert.rejects(buildGenesis(context(), config([{ address, balance: 10n }])), {
+      message: `Duplicate account: ${address}`,
+    })
+  })
+
+  it('preserves distinct accounts, their casing, contract code, and total supply', async () => {
+    const genesis = await buildGenesis(
+      context(),
+      config([
+        { address: checksumAccount, balance: 10n },
+        { address: otherAccount, balance: 20n },
+      ]),
+    )
+
+    assert.equal(genesis.alloc[checksumAccount].balance, '0xa')
+    assert.equal(genesis.alloc[otherAccount].balance, '0x14')
+    assert.equal(genesis.alloc[account], undefined)
+    assert.equal(genesis.alloc[implementationAddress].code, '0x00')
+    assert.equal(genesis.alloc[implementationAddress].nonce, '0x1')
+    const supply = genesis.alloc[nativeCoinAutorityAddress].storage?.[slotIndex(2n)]
+    assert.ok(supply)
+    assert.equal(fromHex(supply, 'bigint'), 30n)
+    const addresses = Object.keys(genesis.alloc).map((address) => address.toLowerCase())
+    assert.equal(new Set(addresses).size, addresses.length)
+  })
+})