feat(concordium): Concordium exact schema implementation

typescript/packages/mechanisms/concordium/.prettierignore

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+docs/
+dist/
+node_modules/
+coverage/
+.github/
+**/**/*.json
+*.md

typescript/packages/mechanisms/concordium/.prettierrc

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+{
+  "tabWidth": 2,
+  "useTabs": false,
+  "semi": true,
+  "singleQuote": false,
+  "trailingComma": "all",
+  "bracketSpacing": true,
+  "arrowParens": "avoid",
+  "printWidth": 100,
+  "proseWrap": "never"
+}

typescript/packages/mechanisms/concordium/CHANGELOG.md

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+# @x402/concordium Changelog
+
+## 1.0.0
+
+- Implement x402 v2 protocol support for the Concordium mechanism (exact scheme).

typescript/packages/mechanisms/concordium/TODO.md

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+# @x402/concordium

typescript/packages/mechanisms/concordium/eslint.config.mjs

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+import js from "@eslint/js";
+import ts from "@typescript-eslint/eslint-plugin";
+import tsParser from "@typescript-eslint/parser";
+import prettier from "eslint-plugin-prettier";
+import jsdoc from "eslint-plugin-jsdoc";
+import importPlugin from "eslint-plugin-import";
+
+export default [
+  {
+    ignores: ["dist/**", "node_modules/**"],
+  },
+  {
+    files: ["**/*.ts", "**/*.tsx"],
+    ignores: ["**/*.test.ts", "test/**/*"],
+    languageOptions: {
+      parser: tsParser,
+      sourceType: "module",
+      ecmaVersion: 2020,
+      globals: {
+        process: "readonly",
+        __dirname: "readonly",
+        module: "readonly",
+        require: "readonly",
+        Buffer: "readonly",
+        exports: "readonly",
+        setTimeout: "readonly",
+        clearTimeout: "readonly",
+        setInterval: "readonly",
+        clearInterval: "readonly",
+      },
+    },
+    plugins: {
+      "@typescript-eslint": ts,
+      prettier: prettier,
+      jsdoc: jsdoc,
+      import: importPlugin,
+    },
+    rules: {
+      ...ts.configs.recommended.rules,
+      "import/first": "error",
+      "prettier/prettier": "error",
+      "@typescript-eslint/member-ordering": "error",
+      "@typescript-eslint/no-unused-vars": ["error", { argsIgnorePattern: "^_$" }],
+      "jsdoc/tag-lines": ["error", "any", { startLines: 1 }],
+      "jsdoc/check-alignment": "error",
+      "jsdoc/no-undefined-types": "off",
+      "jsdoc/check-param-names": "error",
+      "jsdoc/check-tag-names": "error",
+      "jsdoc/check-types": "error",
+      "jsdoc/implements-on-classes": "error",
+      "jsdoc/require-description": "error",
+      "jsdoc/require-jsdoc": [
+        "error",
+        {
+          require: {
+            FunctionDeclaration: true,
+            MethodDefinition: true,
+            ClassDeclaration: true,
+            ArrowFunctionExpression: false,
+            FunctionExpression: false,
+          },
+        },
+      ],
+      "jsdoc/require-param": "error",
+      "jsdoc/require-param-description": "error",
+      "jsdoc/require-param-type": "off",
+      "jsdoc/require-returns": "error",
+      "jsdoc/require-returns-description": "error",
+      "jsdoc/require-returns-type": "off",
+      "jsdoc/require-hyphen-before-param-description": ["error", "always"],
+    },
+  },
+  {
+    files: ["**/*.test.ts", "test/**/*"],
+    languageOptions: {
+      parser: tsParser,
+      sourceType: "module",
+      ecmaVersion: 2020,
+    },
+    plugins: {
+      "@typescript-eslint": ts,
+      prettier: prettier,
+    },
+    rules: {
+      "prettier/prettier": "error",
+      "@typescript-eslint/no-unused-vars": ["error", { argsIgnorePattern: "^_" }],
+      "@typescript-eslint/no-explicit-any": "off",
+      "@typescript-eslint/member-ordering": "off",
+    },
+  },
+];

typescript/packages/mechanisms/concordium/package.json

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+{
+  "name": "@x402/concordium",
+  "version": "1.0.0",
+  "main": "./dist/cjs/index.js",
+  "module": "./dist/esm/index.js",
+  "types": "./dist/cjs/index.d.ts",
+  "scripts": {
+    "start": "tsx --env-file=.env index.ts",
+    "build": "tsup",
+    "test": "vitest run",
+    "test:integration": "vitest run --config vitest.integration.config.ts",
+    "test:watch": "vitest",
+    "watch": "tsc --watch",
+    "format": "prettier -c .prettierrc --write \"**/*.{ts,js,cjs,json,md}\"",
+    "format:check": "prettier -c .prettierrc --check \"**/*.{ts,js,cjs,json,md}\"",
+    "lint": "eslint . --ext .ts --fix",
+    "lint:check": "eslint . --ext .ts"
+  },
+  "keywords": [
+    "x402",
+    "payment",
+    "protocol",
+    "concordium"
+  ],
+  "license": "Apache-2.0",
+  "author": "Coinbase Inc.",
+  "repository": "https://github.com/coinbase/x402",
+  "description": "x402 Payment Protocol Concordium Implementation",
+  "devDependencies": {
+    "@eslint/js": "^9.24.0",
+    "@types/node": "^22.13.4",
+    "@typescript-eslint/eslint-plugin": "^8.29.1",
+    "@typescript-eslint/parser": "^8.29.1",
+    "eslint": "^9.24.0",
+    "eslint-plugin-import": "^2.31.0",
+    "eslint-plugin-jsdoc": "^50.6.9",
+    "eslint-plugin-prettier": "^5.2.6",
+    "prettier": "3.5.2",
+    "tsup": "^8.4.0",
+    "tsx": "^4.19.2",
+    "typescript": "^5.7.3",
+    "vite": "^6.2.6",
+    "vite-tsconfig-paths": "^5.1.4",
+    "vitest": "^3.0.5"
+  },
+  "dependencies": {
+    "@x402/core": "workspace:*",
+    "@concordium/web-sdk": "^12.0.0",
+    "zod": "^3.24.2"
+  },
+  "exports": {
+    ".": {
+      "import": {
+        "types": "./dist/esm/index.d.mts",
+        "default": "./dist/esm/index.mjs"
+      },
+      "require": {
+        "types": "./dist/cjs/index.d.ts",
+        "default": "./dist/cjs/index.js"
+      }
+    },
+    "./exact/client": {
+      "import": {
+        "types": "./dist/esm/exact/client/index.d.mts",
+        "default": "./dist/esm/exact/client/index.mjs"
+      },
+      "require": {
+        "types": "./dist/cjs/exact/client/index.d.ts",
+        "default": "./dist/cjs/exact/client/index.js"
+      }
+    },
+    "./exact/server": {
+      "import": {
+        "types": "./dist/esm/exact/server/index.d.mts",
+        "default": "./dist/esm/exact/server/index.mjs"
+      },
+      "require": {
+        "types": "./dist/cjs/exact/server/index.d.ts",
+        "default": "./dist/cjs/exact/server/index.js"
+      }
+    },
+    "./exact/facilitator": {
+      "import": {
+        "types": "./dist/esm/exact/facilitator/index.d.mts",
+        "default": "./dist/esm/exact/facilitator/index.mjs"
+      },
+      "require": {
+        "types": "./dist/cjs/exact/facilitator/index.d.ts",
+        "default": "./dist/cjs/exact/facilitator/index.js"
+      }
+    }
+  },
+  "files": [
+    "dist"
+  ]
+}

typescript/packages/mechanisms/concordium/src/constants.ts

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+import type { Network } from "@x402/core/types";
+
+/** CAIP-2 network identifier for Concordium Mainnet */
+export const CONCORDIUM_MAINNET_CAIP2: Network = "ccd:9dd9ca4d19e9393877d2c44b70f89acb";
+
+/** CAIP-2 network identifier for Concordium Testnet */
+export const CONCORDIUM_TESTNET_CAIP2: Network = "ccd:4221332d34e1694168c2a0c0b3fd0f27";
+
+/** Wildcard matching all Concordium networks */
+export const CONCORDIUM_WILDCARD_CAIP2: Network = "ccd:*";
+
+/** Default mainnet gRPC endpoint (host:port) */
+export const CONCORDIUM_MAINNET_GRPC = "grpc.mainnet.concordium.software:20000";
+
+/** Default testnet gRPC endpoint (host:port) */
+export const CONCORDIUM_TESTNET_GRPC = "grpc.testnet.concordium.com:20000";
+
+/** Default gRPC port */
+export const DEFAULT_GRPC_PORT = 20000;
+
+/** Mainnet block explorer base URL */
+export const CONCORDIUM_MAINNET_EXPLORER = "https://ccdexplorer.io/mainnet";
+
+/** Testnet block explorer base URL */
+export const CONCORDIUM_TESTNET_EXPLORER = "https://ccdexplorer.io/testnet";
+
+/**
+ * Regex pattern for validating Concordium base58check account addresses.
+ * Matches 45–55 alphanumeric characters (base58 alphabet, no 0/O/I/l).
+ */
+export const CONCORDIUM_ADDRESS_REGEX =
+  /^[123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz]{45,55}$/;
+
+/** Default decimals for native CCD */
+export const CCD_DECIMALS = 6;
+
+/** Native CCD uses empty string as asset identifier */
+export const CCD_ASSET_IDENTIFIER = "";
+
+/**
+ * Maximum allowed transaction expiry offset in seconds (spec Rule 7).
+ * Transactions with expiry > now + this value are rejected.
+ */
+export const MAX_EXPIRY_OFFSET_SECONDS = 600;
+
+/**
+ * Default timeout for waiting for ConcordiumBFT finalization (ms).
+ * Concordium has ~10s deterministic finality; 60s provides comfortable margin.
+ */
+export const DEFAULT_FINALIZATION_TIMEOUT_MS = 60_000;
+
+/** Maps CAIP-2 identifiers to gRPC endpoints */
+export const CONCORDIUM_NETWORK_TO_GRPC: ReadonlyMap<Network, string> = new Map([
+  [CONCORDIUM_MAINNET_CAIP2, CONCORDIUM_MAINNET_GRPC],
+  [CONCORDIUM_TESTNET_CAIP2, CONCORDIUM_TESTNET_GRPC],
+]);
+
+/** Maps CAIP-2 identifiers to explorer base URLs */
+export const CONCORDIUM_NETWORK_TO_EXPLORER: ReadonlyMap<Network, string> = new Map([
+  [CONCORDIUM_MAINNET_CAIP2, CONCORDIUM_MAINNET_EXPLORER],
+  [CONCORDIUM_TESTNET_CAIP2, CONCORDIUM_TESTNET_EXPLORER],
+]);
+
+/**
+ * Gets the gRPC endpoint for a Concordium network.
+ *
+ * @param network - CAIP-2 network identifier
+ * @returns gRPC endpoint string (host:port)
+ * @throws If the network is not recognized
+ */
+export function getConcordiumGrpcUrl(network: Network): string {
+  const url = CONCORDIUM_NETWORK_TO_GRPC.get(network);
+  if (!url) {
+    throw new Error(`Unsupported Concordium network: "${network}"`);
+  }
+  return url;
+}
+
+/**
+ * Gets the block explorer URL for a transaction.
+ *
+ * @param network - CAIP-2 network identifier
+ * @param txHash - Transaction hash (hex)
+ * @returns Full explorer URL, or undefined if network not recognized
+ */
+export function getExplorerTxUrl(network: Network, txHash: string): string | undefined {
+  const base = CONCORDIUM_NETWORK_TO_EXPLORER.get(network);
+  return base ? `${base}/transaction/${txHash}` : undefined;
+}
+
+/**
+ * Gets the block explorer URL for an account.
+ *
+ * @param network - CAIP-2 network identifier
+ * @param address - Account address (base58check)
+ * @returns Full explorer URL, or undefined if network not recognized
+ */
+export function getExplorerAccountUrl(network: Network, address: string): string | undefined {
+  const base = CONCORDIUM_NETWORK_TO_EXPLORER.get(network);
+  return base ? `${base}/account/${address}` : undefined;
+}
+
+/**
+ * Parses a gRPC endpoint string into host and port.
+ *
+ * @param grpcUrl - Endpoint in "host:port" format
+ * @returns Tuple of [host, port]
+ */
+export function parseGrpcUrl(grpcUrl: string): [host: string, port: number] {
+  const [host, portStr] = grpcUrl.split(":");
+  return [host, parseInt(portStr, 10) || DEFAULT_GRPC_PORT];
+}

typescript/packages/mechanisms/concordium/src/exact/client/index.ts

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+export { ExactConcordiumScheme } from "./scheme";
+export type { ClientConcordiumConfig } from "./scheme";