feat: new L1 Sepolia token for Blacklight

.env.example

@@ -3,6 +3,9 @@ NEXT_PUBLIC_WALLETCONNECT_PROJECT_ID=
 # Sepolia
 NEXT_PUBLIC_FAUCET_ADDRESS_SEPOLIA=
 
+# Sepolia — Blacklight L1 NIL, reached only via `?chain=blacklight` (not on the landing page).
+NEXT_PUBLIC_FAUCET_ADDRESS_SEPOLIA_BLACKLIGHT=
+
 # Anvil (local dev) - run `./docker/deploy-faucet.sh` to get the address
 # NIL token is pre-deployed at 0x5FbDB2315678afecb367f032d93F642f64180aa3
 NEXT_PUBLIC_FAUCET_ADDRESS_ANVIL=

CLAUDE.md

@@ -33,7 +33,8 @@ Nillion Faucet — a testnet faucet web app for claiming NIL tokens on **L1 (Eth
 **Key source layout:**
 
 - `src/lib/wagmi.ts` — Chain config (Sepolia, Nillion Testnet, Anvil in dev). Defines `nillionTestnet` chain.
-- `src/lib/contracts.ts` — Shared ABIs (faucet + ERC-20), `getFaucetConfig()` resolves contract address + explorer URL per chain. Constants: `NILLION_TESTNET_CHAIN_ID`, `NILLION_TESTNET_RPC_URL`.
+- `src/lib/contracts.ts` — Shared ABIs (faucet + ERC-20), `getFaucetConfig(chainId, variant?)` resolves contract address + explorer URL. Constants: `NILLION_TESTNET_CHAIN_ID`, `NILLION_TESTNET_RPC_URL`, `BLACKLIGHT_CHAIN_PARAM`. Type: `FaucetVariant`.
+- `src/hooks/useFaucetVariant.ts` — resolves the faucet **variant** from `?chain=`; see "Two faucets on one chain" below.
 - `src/lib/l2/faucet.ts` — Server-side viem logic: `sendPayout()` sends ETH then NIL sequentially, `getL2FaucetConfig()` returns drip amounts, `checkFunding()` validates balances. Singleton `FaucetContext` (lazy-initialized).
 - `src/lib/l2/rate-limit.ts` — Redis cooldown: `checkCooldown()`, `markCooldown()`, `getCooldownMs()`. Key prefix: `nillion:faucet:l2:cooldown`.
 - `src/lib/l2/redis.ts` — Singleton ioredis client via `getRedisClient()`.
@@ -49,6 +50,19 @@ Nillion Faucet — a testnet faucet web app for claiming NIL tokens on **L1 (Eth
 
 **L1 contract architecture:** `NILFaucet` wraps an immutable ERC-20 `TOKEN` reference. `canClaim(address)` returns `(bool, string)` where the string is a reason code: `PAUSED`, `DRIP_0`, `EMPTY`, `COOLDOWN`. The frontend maps these to UI states directly.
 
+**Two faucets on one chain (the `variant` concept):** Sepolia hosts the original NIL faucet **and** one for Blacklight L1's NIL — a different ERC-20 at a different address, deployed 2026-08-25. `TOKEN` is immutable, so one contract cannot serve both tokens; each needs its own `NILFaucet` instance.
+
+Because both are on chain 11155111, `chainId` cannot distinguish them, and the app was keyed on `chainId` alone. A **variant** does the disambiguating:
+
+- `?chain=blacklight` → variant `"blacklight"` → `NEXT_PUBLIC_FAUCET_ADDRESS_SEPOLIA_BLACKLIGHT`
+- anything else (`?chain=L1`, `?chain=L2`, no param) → variant `undefined` → the chain's default, i.e. **existing behaviour, unchanged**
+
+`useFaucetVariant()` reads it **synchronously** rather than in an effect, on purpose: resolving a tick late would let the first render of `?chain=blacklight` read the _default_ faucet, painting the wrong token's balance and drip, and a fast click could send `claim()` to the wrong contract. It is `window`-guarded for SSR.
+
+Everything downstream is automatic — the UI reads `TOKEN`, `dripAmount` and `cooldownSeconds` _from the contract_, so pointing at a different faucet gets the right token, drip and cooldown with no further wiring.
+
+**It is deliberately absent from the landing page.** No `NetworkCard` renders it; the URL is the only way in. If its env var is unset the card says "Faucet not configured" rather than falling back to the other faucet — a silent fallback between two different NILs is the one failure mode worth refusing outright.
+
 **L2 flow:** Client POSTs wallet address → server checks Redis cooldown → server sends ETH transfer then ERC-20 transfer sequentially (avoids nonce collisions) → marks cooldown in Redis → returns both tx hashes.
 
 ## Code Conventions
@@ -69,6 +83,7 @@ See `.env.example`. Key vars:
 
 - `NEXT_PUBLIC_WALLETCONNECT_PROJECT_ID` — Required for WalletConnect
 - `NEXT_PUBLIC_FAUCET_ADDRESS_SEPOLIA` / `NEXT_PUBLIC_FAUCET_ADDRESS_ANVIL` — Contract addresses per chain
+- `NEXT_PUBLIC_FAUCET_ADDRESS_SEPOLIA_BLACKLIGHT` — the Blacklight L1 NIL faucet on Sepolia, reached only via `?chain=blacklight`. Needs its own deployed `NILFaucet` (drip 20 NIL = `20000000`, cooldown `86400`), funded with that token
 - `NEXT_PUBLIC_SEPOLIA_RPC_URL` / `NEXT_PUBLIC_ANVIL_RPC_URL` — Optional RPC overrides
 
 **L2 (server-side):**

src/app/page.tsx

@@ -7,6 +7,7 @@ import { useEffect, useState } from "react";
 import { useConnection } from "wagmi";
 
 import { useChainFromUrl } from "@/hooks/useChainFromUrl";
+import { BLACKLIGHT_CHAIN_PARAM } from "@/lib/contracts";
 
 import { FaucetCard } from "./components/FaucetCard";
 
@@ -108,11 +109,22 @@ interface FaucetPageProps {
   onBack: () => void;
 }
 
+/**
+ * Two faucets now sit on Sepolia, so "Ethereum Sepolia" alone no longer says which one you are
+ * looking at. Naming the Blacklight variant is the cheapest guard against claiming from the
+ * wrong token and concluding the faucet is broken.
+ */
+function networkLabelFor(chainParam: string): string {
+  if (chainParam === "L2") return "Nillion Testnet";
+  if (chainParam.toLowerCase() === BLACKLIGHT_CHAIN_PARAM) return "Blacklight L1 · Ethereum Sepolia";
+  return "Ethereum Sepolia";
+}
+
 function FaucetPage({ chainParam, onBack }: FaucetPageProps): React.JSX.Element {
   const { isConnected } = useConnection();
   useChainFromUrl();
 
-  const networkLabel = chainParam === "L2" ? "Nillion Testnet" : "Ethereum Sepolia";
+  const networkLabel = networkLabelFor(chainParam);
 
   return (
     <main className="min-h-screen flex flex-col items-center justify-center p-8">

src/hooks/useChainFromUrl.ts

@@ -1,13 +1,14 @@
 import { useEffect } from "react";
 import { useChainId, useSwitchChain } from "wagmi";
 
-import { NILLION_TESTNET_CHAIN_ID } from "@/lib/contracts";
+import { BLACKLIGHT_CHAIN_PARAM, NILLION_TESTNET_CHAIN_ID } from "@/lib/contracts";
 
 const SEPOLIA_CHAIN_ID = 11155111;
 
 const CHAIN_PARAM_MAP: Record<string, number> = {
   l1: SEPOLIA_CHAIN_ID,
   l2: NILLION_TESTNET_CHAIN_ID,
+  [BLACKLIGHT_CHAIN_PARAM]: SEPOLIA_CHAIN_ID,
 };
 
 export function useChainFromUrl(): void {

src/hooks/useClaim.ts

@@ -4,6 +4,7 @@ import { useCallback, useEffect, useRef, useState } from "react";
 import { toast } from "sonner";
 import { useConnection, useChainId, useWaitForTransactionReceipt, useWriteContract } from "wagmi";
 
+import { useFaucetVariant } from "@/hooks/useFaucetVariant";
 import { FAUCET_ABI, getFaucetConfig } from "@/lib/contracts";
 
 /** Status of the claim transaction lifecycle */
@@ -33,7 +34,8 @@ export interface UseClaimResult {
 export function useClaim(onSuccess?: () => void): UseClaimResult {
   const { address } = useConnection();
   const chainId = useChainId();
-  const { address: faucetAddress, explorerUrl } = getFaucetConfig(chainId);
+  const variant = useFaucetVariant();
+  const { address: faucetAddress, explorerUrl } = getFaucetConfig(chainId, variant);
 
   const [error, setError] = useState<Error | null>(null);
   const toastShownForTx = useRef<string | null>(null);

src/hooks/useFaucetStatus.ts

@@ -2,6 +2,7 @@
 
 import { useConnection, useChainId, useChains, useReadContract, useReadContracts } from "wagmi";
 
+import { useFaucetVariant } from "@/hooks/useFaucetVariant";
 import { ERC20_ABI, FAUCET_ABI, getFaucetConfig } from "@/lib/contracts";
 
 /** Faucet status and user eligibility data */
@@ -55,8 +56,10 @@ export function useFaucetStatus(): FaucetStatus {
   const chainId = useChainId();
   const chains = useChains();
 
+  const variant = useFaucetVariant();
+
   const chainName = chains.find((c) => c.id === chainId)?.name ?? "Unknown";
-  const { address: faucetAddress, explorerUrl } = getFaucetConfig(chainId);
+  const { address: faucetAddress, explorerUrl } = getFaucetConfig(chainId, variant);
 
   // First, read the token address from the faucet contract
   const {

src/hooks/useFaucetVariant.ts

@@ -0,0 +1,15 @@
+"use client";
+
+import { BLACKLIGHT_CHAIN_PARAM, type FaucetVariant } from "@/lib/contracts";
+
+/**
+ * Which faucet on the current chain the URL is asking for.
+ *
+ * Sepolia hosts two faucets — the original NIL one and the Blacklight L1 one — so `chainId`
+ * cannot tell them apart. `?chain=blacklight` selects the second
+ */
+export function useFaucetVariant(): FaucetVariant | undefined {
+  if (typeof window === "undefined") return undefined;
+  const param = new URLSearchParams(window.location.search).get("chain")?.toLowerCase();
+  return param === BLACKLIGHT_CHAIN_PARAM ? "blacklight" : undefined;
+}

src/lib/contracts.ts

@@ -98,14 +98,30 @@ export const ERC20_ABI = [
 
 const SEPOLIA_CHAIN_ID = 11155111;
 
+/**
+ * A faucet VARIANT distinguishes two faucets that live on the SAME chain, which chainId
+ * alone cannot. Sepolia now hosts two: the original NIL faucet, and one for the Blacklight
+ * L1 NIL token deployed 2026-08-25 — a different ERC-20 at a different address.
+ */
+export type FaucetVariant = "blacklight";
+
+/** URL value that selects the Blacklight faucet: `?chain=blacklight`. Deliberately not on the landing page. */
+export const BLACKLIGHT_CHAIN_PARAM = "blacklight";
+
 function isHexAddress(value: string | undefined): value is `0x${string}` {
   return typeof value === "string" && /^0x[a-fA-F0-9]{40}$/.test(value);
 }
 
 // Contract addresses per chain - loaded from environment
-function getFaucetAddress(chainId: number): `0x${string}` | undefined {
+function getFaucetAddress(chainId: number, variant?: FaucetVariant): `0x${string}` | undefined {
   if (chainId === SEPOLIA_CHAIN_ID) {
-    const addr = process.env.NEXT_PUBLIC_FAUCET_ADDRESS_SEPOLIA;
+    // Each branch names its env var LITERALLY. `process.env[someKey]` is not statically
+    // analysable, so Next inlines nothing and every NEXT_PUBLIC_* read comes back undefined
+    // in the browser — a faucet that silently reports "not configured" in production only.
+    const addr =
+      variant === "blacklight"
+        ? process.env.NEXT_PUBLIC_FAUCET_ADDRESS_SEPOLIA_BLACKLIGHT
+        : process.env.NEXT_PUBLIC_FAUCET_ADDRESS_SEPOLIA;
     return isHexAddress(addr) ? addr : undefined;
   }
   if (chainId === ANVIL_CHAIN_ID) {
@@ -125,12 +141,15 @@ function getExplorerUrl(chainId: number): string {
   return explorerUrls[chainId] || "https://etherscan.io";
 }
 
-export function getFaucetConfig(chainId: number): {
+export function getFaucetConfig(
+  chainId: number,
+  variant?: FaucetVariant,
+): {
   address: `0x${string}` | undefined;
   explorerUrl: string;
 } {
   return {
-    address: getFaucetAddress(chainId),
+    address: getFaucetAddress(chainId, variant),
     explorerUrl: getExplorerUrl(chainId),
   };
 }