diff --git a/lib/airdrop/siwe-verify.test.ts b/lib/airdrop/siwe-verify.test.ts
new file mode 100644
index 0000000..5cb14c6
--- /dev/null
+++ b/lib/airdrop/siwe-verify.test.ts
@@ -0,0 +1,117 @@
+import { describe, expect, it, vi, beforeEach } from "vitest";
+import { SiweMessage } from "siwe";
+import { privateKeyToAccount } from "viem/accounts";
+
+const TEST_KEY = "0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80";
+const account = privateKeyToAccount(TEST_KEY);
+
+beforeEach(() => {
+  vi.stubEnv("NEXT_PUBLIC_AIRDROP_MODE", "");
+  vi.unstubAllEnvs();
+  vi.stubEnv("NEXT_PUBLIC_AIRDROP_MODE", "");
+});
+
+function buildMessage(overrides: Partial<SiweMessage> = {}): SiweMessage {
+  return new SiweMessage({
+    domain: "plotlink.xyz",
+    address: account.address,
+    statement: "PlotLink Buy-Back Sprint activation",
+    uri: "https://plotlink.xyz/airdrop",
+    version: "1",
+    chainId: 8453,
+    nonce: "abcd1234",
+    issuedAt: new Date().toISOString(),
+    ...overrides,
+  });
+}
+
+async function signMessage(msg: SiweMessage): Promise<string> {
+  const prepared = msg.prepareMessage();
+  return account.signMessage({ message: prepared });
+}
+
+describe("verifySiweRequest", () => {
+  it("accepts a valid signature within freshness window", async () => {
+    const { verifySiweRequest } = await import("./siwe-verify");
+    const msg = buildMessage();
+    const sig = await signMessage(msg);
+    const result = await verifySiweRequest(msg.prepareMessage(), sig);
+    expect(result).toEqual({ ok: true, address: account.address.toLowerCase() });
+  });
+
+  it("rejects an invalid signature", async () => {
+    const { verifySiweRequest } = await import("./siwe-verify");
+    const msg = buildMessage();
+    const badSig = "0x" + "ab".repeat(65);
+    const result = await verifySiweRequest(msg.prepareMessage(), badSig);
+    expect(result.ok).toBe(false);
+    if (!result.ok) expect(result.error).toBe("invalid_signature");
+  });
+
+  it("rejects wrong domain", async () => {
+    const { verifySiweRequest } = await import("./siwe-verify");
+    const msg = buildMessage({ domain: "evil.com" });
+    const sig = await signMessage(msg);
+    const result = await verifySiweRequest(msg.prepareMessage(), sig);
+    expect(result).toEqual({ ok: false, error: "domain_mismatch" });
+  });
+
+  it("rejects wrong URI", async () => {
+    const { verifySiweRequest } = await import("./siwe-verify");
+    const msg = buildMessage({ uri: "https://evil.com/airdrop" });
+    const sig = await signMessage(msg);
+    const result = await verifySiweRequest(msg.prepareMessage(), sig);
+    expect(result).toEqual({ ok: false, error: "uri_mismatch" });
+  });
+
+  it("rejects wrong chain ID", async () => {
+    const { verifySiweRequest } = await import("./siwe-verify");
+    const msg = buildMessage({ chainId: 1 });
+    const sig = await signMessage(msg);
+    const result = await verifySiweRequest(msg.prepareMessage(), sig);
+    expect(result).toEqual({ ok: false, error: "chain_id_mismatch" });
+  });
+
+  it("rejects wrong statement", async () => {
+    const { verifySiweRequest } = await import("./siwe-verify");
+    const msg = buildMessage({ statement: "Wrong statement" });
+    const sig = await signMessage(msg);
+    const result = await verifySiweRequest(msg.prepareMessage(), sig);
+    expect(result).toEqual({ ok: false, error: "statement_mismatch" });
+  });
+
+  it("rejects expired signature (older than SIGNATURE_FRESHNESS_MIN)", async () => {
+    const { verifySiweRequest } = await import("./siwe-verify");
+    const old = new Date(Date.now() - 15 * 60_000);
+    const msg = buildMessage({ issuedAt: old.toISOString() });
+    const sig = await signMessage(msg);
+    const result = await verifySiweRequest(msg.prepareMessage(), sig);
+    expect(result).toEqual({ ok: false, error: "expired" });
+  });
+
+  it("rejects signature issued in the future", async () => {
+    const { verifySiweRequest } = await import("./siwe-verify");
+    const future = new Date(Date.now() + 5 * 60_000);
+    const msg = buildMessage({ issuedAt: future.toISOString() });
+    const sig = await signMessage(msg);
+    const result = await verifySiweRequest(msg.prepareMessage(), sig);
+    expect(result).toEqual({ ok: false, error: "issued_in_future" });
+  });
+
+  it("rejects message with past expirationTime", async () => {
+    const { verifySiweRequest } = await import("./siwe-verify");
+    const past = new Date(Date.now() - 60_000);
+    const msg = buildMessage({ expirationTime: past.toISOString() });
+    const sig = await signMessage(msg);
+    const result = await verifySiweRequest(msg.prepareMessage(), sig);
+    expect(result.ok).toBe(false);
+    if (!result.ok) expect(result.error).toBe("expired");
+  });
+
+  it("rejects unparseable message", async () => {
+    const { verifySiweRequest } = await import("./siwe-verify");
+    const result = await verifySiweRequest("not a siwe message", "0x1234");
+    expect(result.ok).toBe(false);
+    if (!result.ok) expect(result.error).toBe("invalid_message");
+  });
+});
diff --git a/lib/airdrop/siwe-verify.ts b/lib/airdrop/siwe-verify.ts
new file mode 100644
index 0000000..bf68496
--- /dev/null
+++ b/lib/airdrop/siwe-verify.ts
@@ -0,0 +1,63 @@
+import { SiweMessage } from "siwe";
+import { getAirdropConfig } from "./config";
+
+export async function verifySiweRequest(
+  message: string,
+  signature: string,
+): Promise<{ ok: true; address: string } | { ok: false; error: string }> {
+  const config = getAirdropConfig();
+
+  let parsed: SiweMessage;
+  try {
+    parsed = new SiweMessage(message);
+  } catch {
+    return { ok: false, error: "invalid_message" };
+  }
+
+  if (parsed.domain !== config.SIWE_DOMAIN) {
+    return { ok: false, error: "domain_mismatch" };
+  }
+  if (parsed.uri !== config.SIWE_URI) {
+    return { ok: false, error: "uri_mismatch" };
+  }
+  if (parsed.chainId !== config.SIWE_CHAIN_ID) {
+    return { ok: false, error: "chain_id_mismatch" };
+  }
+  if (parsed.statement !== config.SIWE_STATEMENT) {
+    return { ok: false, error: "statement_mismatch" };
+  }
+
+  if (parsed.issuedAt) {
+    const issuedAt = new Date(parsed.issuedAt);
+    const now = new Date();
+    const ageMin = (now.getTime() - issuedAt.getTime()) / 60_000;
+    if (ageMin > config.SIGNATURE_FRESHNESS_MIN) {
+      return { ok: false, error: "expired" };
+    }
+    if (ageMin < -1) {
+      return { ok: false, error: "issued_in_future" };
+    }
+  }
+
+  try {
+    const result = await parsed.verify(
+      { signature, domain: config.SIWE_DOMAIN },
+      { suppressExceptions: true },
+    );
+
+    if (!result.success) {
+      const errorType = result.error?.type ?? "unknown";
+      if (errorType.toLowerCase().includes("signature")) {
+        return { ok: false, error: "invalid_signature" };
+      }
+      if (errorType.toLowerCase().includes("expired")) {
+        return { ok: false, error: "expired" };
+      }
+      return { ok: false, error: errorType };
+    }
+
+    return { ok: true, address: result.data.address.toLowerCase() };
+  } catch {
+    return { ok: false, error: "invalid_signature" };
+  }
+}
diff --git a/package-lock.json b/package-lock.json
index 1646679..3187aa6 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "plotlink",
-  "version": "1.29.1",
+  "version": "1.30.2",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "plotlink",
-      "version": "1.29.1",
+      "version": "1.30.2",
       "workspaces": [
         "packages/*"
       ],
@@ -29,6 +29,7 @@
         "rehype-sanitize": "^6.0.0",
         "remark-breaks": "^4.0.0",
         "remark-gfm": "^4.0.1",
+        "siwe": "^2.3.2",
         "viem": "^2.47.2",
         "wagmi": "^2.19.5"
       },
@@ -8717,6 +8718,49 @@
         "superstruct": "^2.0.2"
       }
     },
+    "node_modules/@spruceid/siwe-parser": {
+      "version": "2.1.2",
+      "resolved": "https://registry.npmjs.org/@spruceid/siwe-parser/-/siwe-parser-2.1.2.tgz",
+      "integrity": "sha512-d/r3S1LwJyMaRAKQ0awmo9whfXeE88Qt00vRj91q5uv5ATtWIQEGJ67Yr5eSZw5zp1/fZCXZYuEckt8lSkereQ==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "@noble/hashes": "^1.1.2",
+        "apg-js": "^4.3.0",
+        "uri-js": "^4.4.1",
+        "valid-url": "^1.0.9"
+      }
+    },
+    "node_modules/@stablelib/binary": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/@stablelib/binary/-/binary-1.0.1.tgz",
+      "integrity": "sha512-ClJWvmL6UBM/wjkvv/7m5VP3GMr9t0osr4yVgLZsLCOz4hGN9gIAFEqnJ0TsSMAN+n840nf2cHZnA5/KFqHC7Q==",
+      "license": "MIT",
+      "dependencies": {
+        "@stablelib/int": "^1.0.1"
+      }
+    },
+    "node_modules/@stablelib/int": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/@stablelib/int/-/int-1.0.1.tgz",
+      "integrity": "sha512-byr69X/sDtDiIjIV6m4roLVWnNNlRGzsvxw+agj8CIEazqWGOQp2dTYgQhtyVXV9wpO6WyXRQUzLV/JRNumT2w==",
+      "license": "MIT"
+    },
+    "node_modules/@stablelib/random": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/@stablelib/random/-/random-1.0.2.tgz",
+      "integrity": "sha512-rIsE83Xpb7clHPVRlBj8qNe5L8ISQOzjghYQm/dZ7VaM2KHYwMW5adjQjrzTZCchFnNCNhkwtnOBa9HTMJCI8w==",
+      "license": "MIT",
+      "dependencies": {
+        "@stablelib/binary": "^1.0.1",
+        "@stablelib/wipe": "^1.0.1"
+      }
+    },
+    "node_modules/@stablelib/wipe": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/@stablelib/wipe/-/wipe-1.0.1.tgz",
+      "integrity": "sha512-WfqfX/eXGiAd3RJe4VU2snh/ZPwtSjLG4ynQ/vYzvghTh7dHFcI1wl+nrkWG6lGhukOxOsUHfv8dUXr58D0ayg==",
+      "license": "MIT"
+    },
     "node_modules/@supabase/auth-js": {
       "version": "2.104.1",
       "resolved": "https://registry.npmjs.org/@supabase/auth-js/-/auth-js-2.104.1.tgz",
@@ -10850,6 +10894,13 @@
         "acorn": "^6.0.0 || ^7.0.0 || ^8.0.0"
       }
     },
+    "node_modules/aes-js": {
+      "version": "4.0.0-beta.5",
+      "resolved": "https://registry.npmjs.org/aes-js/-/aes-js-4.0.0-beta.5.tgz",
+      "integrity": "sha512-G965FqalsNyrPqgEGON7nIx1e/OVENSgiEIzyC63haUMuvNnwIgIjMs52hlTCKhkBny7A2ORNlfY9Zu+jmGk1Q==",
+      "license": "MIT",
+      "peer": true
+    },
     "node_modules/agent-base": {
       "version": "7.1.4",
       "resolved": "https://registry.npmjs.org/agent-base/-/agent-base-7.1.4.tgz",
@@ -10932,6 +10983,12 @@
         "node": ">= 8"
       }
     },
+    "node_modules/apg-js": {
+      "version": "4.4.0",
+      "resolved": "https://registry.npmjs.org/apg-js/-/apg-js-4.4.0.tgz",
+      "integrity": "sha512-fefmXFknJmtgtNEXfPwZKYkMFX4Fyeyz+fNF6JWp87biGOPslJbCBVU158zvKRZfHBKnJDy8CMM40oLFGkXT8Q==",
+      "license": "BSD-2-Clause"
+    },
     "node_modules/argparse": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/argparse/-/argparse-2.0.1.tgz",
@@ -13335,6 +13392,114 @@
         "url": "https://paulmillr.com/funding/"
       }
     },
+    "node_modules/ethers": {
+      "version": "6.16.0",
+      "resolved": "https://registry.npmjs.org/ethers/-/ethers-6.16.0.tgz",
+      "integrity": "sha512-U1wulmetNymijEhpSEQ7Ct/P/Jw9/e7R1j5XIbPRydgV2DjLVMsULDlNksq3RQnFgKoLlZf88ijYtWEXcPa07A==",
+      "funding": [
+        {
+          "type": "individual",
+          "url": "https://github.com/sponsors/ethers-io/"
+        },
+        {
+          "type": "individual",
+          "url": "https://www.buymeacoffee.com/ricmoo"
+        }
+      ],
+      "license": "MIT",
+      "peer": true,
+      "dependencies": {
+        "@adraffy/ens-normalize": "1.10.1",
+        "@noble/curves": "1.2.0",
+        "@noble/hashes": "1.3.2",
+        "@types/node": "22.7.5",
+        "aes-js": "4.0.0-beta.5",
+        "tslib": "2.7.0",
+        "ws": "8.17.1"
+      },
+      "engines": {
+        "node": ">=14.0.0"
+      }
+    },
+    "node_modules/ethers/node_modules/@adraffy/ens-normalize": {
+      "version": "1.10.1",
+      "resolved": "https://registry.npmjs.org/@adraffy/ens-normalize/-/ens-normalize-1.10.1.tgz",
+      "integrity": "sha512-96Z2IP3mYmF1Xg2cDm8f1gWGf/HUVedQ3FMifV4kG/PQ4yEP51xDtRAEfhVNt5f/uzpNkZHwWQuUcu6D6K+Ekw==",
+      "license": "MIT",
+      "peer": true
+    },
+    "node_modules/ethers/node_modules/@noble/curves": {
+      "version": "1.2.0",
+      "resolved": "https://registry.npmjs.org/@noble/curves/-/curves-1.2.0.tgz",
+      "integrity": "sha512-oYclrNgRaM9SsBUBVbb8M6DTV7ZHRTKugureoYEncY5c65HOmRzvSiTE3y5CYaPYJA/GVkrhXEoF0M3Ya9PMnw==",
+      "license": "MIT",
+      "peer": true,
+      "dependencies": {
+        "@noble/hashes": "1.3.2"
+      },
+      "funding": {
+        "url": "https://paulmillr.com/funding/"
+      }
+    },
+    "node_modules/ethers/node_modules/@noble/hashes": {
+      "version": "1.3.2",
+      "resolved": "https://registry.npmjs.org/@noble/hashes/-/hashes-1.3.2.tgz",
+      "integrity": "sha512-MVC8EAQp7MvEcm30KWENFjgR+Mkmf+D189XJTkFIlwohU5hcBbn1ZkKq7KVTi2Hme3PMGF390DaL52beVrIihQ==",
+      "license": "MIT",
+      "peer": true,
+      "engines": {
+        "node": ">= 16"
+      },
+      "funding": {
+        "url": "https://paulmillr.com/funding/"
+      }
+    },
+    "node_modules/ethers/node_modules/@types/node": {
+      "version": "22.7.5",
+      "resolved": "https://registry.npmjs.org/@types/node/-/node-22.7.5.tgz",
+      "integrity": "sha512-jML7s2NAzMWc//QSJ1a3prpk78cOPchGvXJsC3C6R6PSMoooztvRVQEz89gmBTBY1SPMaqo5teB4uNHPdetShQ==",
+      "license": "MIT",
+      "peer": true,
+      "dependencies": {
+        "undici-types": "~6.19.2"
+      }
+    },
+    "node_modules/ethers/node_modules/tslib": {
+      "version": "2.7.0",
+      "resolved": "https://registry.npmjs.org/tslib/-/tslib-2.7.0.tgz",
+      "integrity": "sha512-gLXCKdN1/j47AiHiOkJN69hJmcbGTHI0ImLmbYLHykhgeN0jVGola9yVjFgzCUklsZQMW55o+dW7IXv3RCXDzA==",
+      "license": "0BSD",
+      "peer": true
+    },
+    "node_modules/ethers/node_modules/undici-types": {
+      "version": "6.19.8",
+      "resolved": "https://registry.npmjs.org/undici-types/-/undici-types-6.19.8.tgz",
+      "integrity": "sha512-ve2KP6f/JnbPBFyobGHuerC9g1FYGn/F8n1LWTwNxCEzd6IfqTwUQcNXgEtmmQ6DlRrC1hrSrBnCZPokRrDHjw==",
+      "license": "MIT",
+      "peer": true
+    },
+    "node_modules/ethers/node_modules/ws": {
+      "version": "8.17.1",
+      "resolved": "https://registry.npmjs.org/ws/-/ws-8.17.1.tgz",
+      "integrity": "sha512-6XQFvXTkbfUOZOKKILFG1PDK2NDQs4azKQl26T0YS5CxqWLgXajbPZ+h4gZekJyRqFU8pvnbAbbs/3TgRPy+GQ==",
+      "license": "MIT",
+      "peer": true,
+      "engines": {
+        "node": ">=10.0.0"
+      },
+      "peerDependencies": {
+        "bufferutil": "^4.0.1",
+        "utf-8-validate": ">=5.0.2"
+      },
+      "peerDependenciesMeta": {
+        "bufferutil": {
+          "optional": true
+        },
+        "utf-8-validate": {
+          "optional": true
+        }
+      }
+    },
     "node_modules/eventemitter2": {
       "version": "6.4.9",
       "resolved": "https://registry.npmjs.org/eventemitter2/-/eventemitter2-6.4.9.tgz",
@@ -17797,7 +17962,6 @@
       "version": "2.3.1",
       "resolved": "https://registry.npmjs.org/punycode/-/punycode-2.3.1.tgz",
       "integrity": "sha512-vYt7UD1U9Wg6138shLtLOvdAu+8DsC/ilFtEVHcH+wydcSpNE20AfSOduf6MkRFahL5FY7X1oU7nKVZFtfq8Fg==",
-      "dev": true,
       "license": "MIT",
       "engines": {
         "node": ">=6"
@@ -18719,6 +18883,21 @@
       "dev": true,
       "license": "ISC"
     },
+    "node_modules/siwe": {
+      "version": "2.3.2",
+      "resolved": "https://registry.npmjs.org/siwe/-/siwe-2.3.2.tgz",
+      "integrity": "sha512-aSf+6+Latyttbj5nMu6GF3doMfv2UYj83hhwZgUF20ky6fTS83uVhkQABdIVnEuS8y1bBdk7p6ltb9SmlhTTlA==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "@spruceid/siwe-parser": "^2.1.2",
+        "@stablelib/random": "^1.0.1",
+        "uri-js": "^4.4.1",
+        "valid-url": "^1.0.9"
+      },
+      "peerDependencies": {
+        "ethers": "^5.6.8 || ^6.0.8"
+      }
+    },
     "node_modules/socket.io-client": {
       "version": "4.8.3",
       "resolved": "https://registry.npmjs.org/socket.io-client/-/socket.io-client-4.8.3.tgz",
@@ -19986,7 +20165,6 @@
       "version": "4.4.1",
       "resolved": "https://registry.npmjs.org/uri-js/-/uri-js-4.4.1.tgz",
       "integrity": "sha512-7rKUyy33Q1yc98pQ1DAmLtwX109F7TIfWlW1Ydo8Wl1ii1SeHieeh0HHfPeL2fMXK6z0s8ecKs9frCuLJvndBg==",
-      "dev": true,
       "license": "BSD-2-Clause",
       "dependencies": {
         "punycode": "^2.1.0"
@@ -20090,6 +20268,11 @@
         "uuid": "dist/bin/uuid"
       }
     },
+    "node_modules/valid-url": {
+      "version": "1.0.9",
+      "resolved": "https://registry.npmjs.org/valid-url/-/valid-url-1.0.9.tgz",
+      "integrity": "sha512-QQDsV8OnSf5Uc30CKSwG9lnhMPe6exHtTXLRYX8uMwKENy640pU+2BgBL0LRbDh/eYRahNCS7aewCx0wf3NYVA=="
+    },
     "node_modules/valtio": {
       "version": "1.13.2",
       "resolved": "https://registry.npmjs.org/valtio/-/valtio-1.13.2.tgz",
diff --git a/package.json b/package.json
index ef61efd..782cf70 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "plotlink",
-  "version": "1.30.1",
+  "version": "1.30.2",
   "private": true,
   "workspaces": [
     "packages/*"
@@ -33,6 +33,7 @@
     "rehype-sanitize": "^6.0.0",
     "remark-breaks": "^4.0.0",
     "remark-gfm": "^4.0.1",
+    "siwe": "^2.3.2",
     "viem": "^2.47.2",
     "wagmi": "^2.19.5"
   },