diff --git a/.gitignore b/.gitignore
index 83d32db..777b53b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -29,6 +29,13 @@ bin/
 .env
 local.properties
 
+# Grid CLI credentials
+.grid-credentials
+.claude/settings.local.json
+
+# CLI build output
+cli/dist/
+
 # Figma design tokens (local reference only)
 mintlify/tokens/
 
diff --git a/Makefile b/Makefile
index 02b6fe1..053a41a 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-.PHONY: install build build-openapi mint lint lint-openapi lint-markdown
+.PHONY: install build build-openapi mint lint lint-openapi lint-markdown cli-install cli-build cli
 
 install:
 	npm install
@@ -21,4 +21,13 @@ lint-openapi:
 	npm run lint:openapi
 
 lint-markdown:
-	npm run lint:markdown 
\ No newline at end of file
+	npm run lint:markdown
+
+cli-install:
+	cd cli && npm install
+
+cli-build:
+	cd cli && npm run build
+
+cli:
+	cd cli && npm run dev --
\ No newline at end of file
diff --git a/cli/package.json b/cli/package.json
new file mode 100644
index 0000000..49b0286
--- /dev/null
+++ b/cli/package.json
@@ -0,0 +1,25 @@
+{
+  "name": "grid-cli",
+  "version": "1.0.0",
+  "description": "CLI tool for Grid API",
+  "main": "dist/index.js",
+  "bin": {
+    "grid": "./dist/index.js"
+  },
+  "scripts": {
+    "build": "tsc",
+    "dev": "ts-node src/index.ts",
+    "start": "node dist/index.js",
+    "clean": "rm -rf dist"
+  },
+  "dependencies": {
+    "commander": "^12.1.0"
+  },
+  "devDependencies": {
+    "@types/node": "^20.0.0",
+    "ts-node": "^10.9.2",
+    "typescript": "^5.4.0"
+  },
+  "author": "Lightspark",
+  "license": "Apache-2.0"
+}
diff --git a/cli/src/client.ts b/cli/src/client.ts
new file mode 100644
index 0000000..30acc86
--- /dev/null
+++ b/cli/src/client.ts
@@ -0,0 +1,129 @@
+import { GridConfig } from "./config";
+
+export interface ApiResponse<T> {
+  success: boolean;
+  data?: T;
+  error?: {
+    status: number;
+    code?: string;
+    message: string;
+    details?: unknown;
+  };
+}
+
+export interface PaginatedResponse<T> {
+  data: T[];
+  hasMore: boolean;
+  nextCursor?: string;
+  totalCount?: number;
+}
+
+export class GridClient {
+  private config: GridConfig;
+
+  constructor(config: GridConfig) {
+    this.config = config;
+  }
+
+  private getAuthHeader(): string {
+    const credentials = `${this.config.apiTokenId}:${this.config.apiClientSecret}`;
+    return `Basic ${Buffer.from(credentials).toString("base64")}`;
+  }
+
+  private buildUrl(
+    path: string,
+    params?: Record<string, string | number | boolean | undefined>
+  ): string {
+    const url = new URL(path, this.config.baseUrl);
+    if (params) {
+      Object.entries(params).forEach(([key, value]) => {
+        if (value !== undefined) {
+          url.searchParams.append(key, String(value));
+        }
+      });
+    }
+    return url.toString();
+  }
+
+  async request<T>(
+    method: string,
+    path: string,
+    options?: {
+      params?: Record<string, string | number | boolean | undefined>;
+      body?: unknown;
+    }
+  ): Promise<ApiResponse<T>> {
+    const url = this.buildUrl(path, options?.params);
+
+    const headers: Record<string, string> = {
+      Authorization: this.getAuthHeader(),
+      Accept: "application/json",
+    };
+
+    const fetchOptions: RequestInit = {
+      method,
+      headers,
+    };
+
+    if (options?.body) {
+      headers["Content-Type"] = "application/json";
+      fetchOptions.body = JSON.stringify(options.body);
+    }
+
+    try {
+      const response = await fetch(url, fetchOptions);
+      const contentType = response.headers.get("content-type");
+      let data: unknown = null;
+
+      if (contentType?.includes("application/json")) {
+        data = await response.json();
+      } else {
+        data = await response.text();
+      }
+
+      if (!response.ok) {
+        const errorData = data as { code?: string; message?: string };
+        return {
+          success: false,
+          error: {
+            status: response.status,
+            code: errorData?.code,
+            message:
+              errorData?.message || response.statusText || "Request failed",
+            details: data,
+          },
+        };
+      }
+
+      return { success: true, data: data as T };
+    } catch (err) {
+      const message = err instanceof Error ? err.message : "Unknown error";
+      return {
+        success: false,
+        error: {
+          status: 0,
+          message: `Network error: ${message}`,
+        },
+      };
+    }
+  }
+
+  async get<T>(
+    path: string,
+    params?: Record<string, string | number | boolean | undefined>
+  ): Promise<ApiResponse<T>> {
+    return this.request<T>("GET", path, { params });
+  }
+
+  async post<T>(path: string, body?: unknown): Promise<ApiResponse<T>> {
+    return this.request<T>("POST", path, { body });
+  }
+
+  async patch<T>(path: string, body?: unknown): Promise<ApiResponse<T>> {
+    return this.request<T>("PATCH", path, { body });
+  }
+
+  async delete<T>(path: string): Promise<ApiResponse<T>> {
+    return this.request<T>("DELETE", path);
+  }
+}
diff --git a/cli/src/config.ts b/cli/src/config.ts
new file mode 100644
index 0000000..2fc464b
--- /dev/null
+++ b/cli/src/config.ts
@@ -0,0 +1,76 @@
+import * as fs from "fs";
+import * as path from "path";
+import * as os from "os";
+
+export interface GridConfig {
+  apiTokenId: string;
+  apiClientSecret: string;
+  baseUrl: string;
+}
+
+const DEFAULT_BASE_URL = "https://api.lightspark.com/grid/2025-10-13";
+const CREDENTIALS_FILE = ".grid-credentials";
+
+function getCredentialsPath(): string {
+  return path.join(os.homedir(), CREDENTIALS_FILE);
+}
+
+function loadCredentialsFile(): Partial<GridConfig> {
+  const credentialsPath = getCredentialsPath();
+  if (fs.existsSync(credentialsPath)) {
+    const content = fs.readFileSync(credentialsPath, "utf-8");
+    return JSON.parse(content);
+  }
+  return {};
+}
+
+export function loadConfig(options: {
+  configPath?: string;
+  baseUrl?: string;
+}): GridConfig {
+  let fileConfig: Partial<GridConfig> = {};
+
+  if (options.configPath) {
+    if (!fs.existsSync(options.configPath)) {
+      throw new Error(`Config file not found: ${options.configPath}`);
+    }
+    const content = fs.readFileSync(options.configPath, "utf-8");
+    fileConfig = JSON.parse(content);
+  } else {
+    fileConfig = loadCredentialsFile();
+  }
+
+  const apiTokenId =
+    process.env.GRID_API_TOKEN_ID || fileConfig.apiTokenId || "";
+  const apiClientSecret =
+    process.env.GRID_API_CLIENT_SECRET || fileConfig.apiClientSecret || "";
+  const baseUrl =
+    options.baseUrl ||
+    process.env.GRID_BASE_URL ||
+    fileConfig.baseUrl ||
+    DEFAULT_BASE_URL;
+
+  if (!apiTokenId || !apiClientSecret) {
+    throw new Error(
+      `Missing credentials. Set GRID_API_TOKEN_ID and GRID_API_CLIENT_SECRET environment variables, ` +
+        `or create ${getCredentialsPath()} with apiTokenId and apiClientSecret fields.`
+    );
+  }
+
+  return { apiTokenId, apiClientSecret, baseUrl };
+}
+
+export function saveCredentials(config: Partial<GridConfig>): void {
+  const credentialsPath = getCredentialsPath();
+  let existing: Partial<GridConfig> = {};
+
+  if (fs.existsSync(credentialsPath)) {
+    const content = fs.readFileSync(credentialsPath, "utf-8");
+    existing = JSON.parse(content);
+  }
+
+  const merged = { ...existing, ...config };
+  fs.writeFileSync(credentialsPath, JSON.stringify(merged, null, 2), {
+    mode: 0o600,
+  });
+}
diff --git a/cli/src/index.ts b/cli/src/index.ts
new file mode 100644
index 0000000..860c550
--- /dev/null
+++ b/cli/src/index.ts
@@ -0,0 +1,42 @@
+#!/usr/bin/env node
+
+import { Command } from "commander";
+import { loadConfig, GridConfig } from "./config";
+import { GridClient } from "./client";
+import { formatError, output } from "./output";
+
+export interface GlobalOptions {
+  config?: string;
+  baseUrl?: string;
+}
+
+const program = new Command();
+
+program
+  .name("grid")
+  .description("CLI for Grid API - manage global payments")
+  .version("1.0.0")
+  .option("-c, --config <path>", "Path to credentials file")
+  .option(
+    "-u, --base-url <url>",
+    "Base URL for API (default: https://api.lightspark.com/grid/2025-10-13)"
+  );
+
+function getClient(options: GlobalOptions): GridClient | null {
+  try {
+    const config = loadConfig({
+      configPath: options.config,
+      baseUrl: options.baseUrl,
+    });
+    return new GridClient(config);
+  } catch (err) {
+    const message = err instanceof Error ? err.message : "Configuration error";
+    output(formatError(message));
+    process.exitCode = 1;
+    return null;
+  }
+}
+
+export { program, getClient, GridClient, GridConfig };
+
+program.parse(process.argv);
diff --git a/cli/src/output.ts b/cli/src/output.ts
new file mode 100644
index 0000000..dfd8060
--- /dev/null
+++ b/cli/src/output.ts
@@ -0,0 +1,56 @@
+import { ApiResponse } from "./client";
+
+export interface CliOutput<T = unknown> {
+  success: boolean;
+  data?: T;
+  error?: {
+    code?: string;
+    message: string;
+    details?: unknown;
+  };
+}
+
+export function formatOutput<T>(response: ApiResponse<T>): string {
+  const output: CliOutput<T> = {
+    success: response.success,
+  };
+
+  if (response.success) {
+    output.data = response.data;
+  } else if (response.error) {
+    output.error = {
+      code: response.error.code,
+      message: response.error.message,
+      details: response.error.details,
+    };
+  }
+
+  return JSON.stringify(output, null, 2);
+}
+
+export function formatError(message: string, details?: unknown): string {
+  const output: CliOutput = {
+    success: false,
+    error: { message, details },
+  };
+  return JSON.stringify(output, null, 2);
+}
+
+export function formatSuccess<T>(data: T): string {
+  const output: CliOutput<T> = {
+    success: true,
+    data,
+  };
+  return JSON.stringify(output, null, 2);
+}
+
+export function output(result: string): void {
+  console.log(result);
+}
+
+export function outputResponse<T>(response: ApiResponse<T>): void {
+  output(formatOutput(response));
+  if (!response.success) {
+    process.exitCode = 1;
+  }
+}
diff --git a/cli/tsconfig.json b/cli/tsconfig.json
new file mode 100644
index 0000000..1951778
--- /dev/null
+++ b/cli/tsconfig.json
@@ -0,0 +1,19 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "commonjs",
+    "lib": ["ES2022"],
+    "outDir": "./dist",
+    "rootDir": "./src",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true,
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist"]
+}
diff --git a/package.json b/package.json
index cfcfe50..c62ee9c 100644
--- a/package.json
+++ b/package.json
@@ -9,7 +9,10 @@
     "lint": "npm run lint:openapi",
     "broken-links": "cd mintlify && mint broken-links",
     "validate": "npm run lint",
-    "test": "echo \"Error: no test specified\" && exit 1"
+    "test": "echo \"Error: no test specified\" && exit 1",
+    "cli:install": "cd cli && npm install",
+    "cli:build": "cd cli && npm run build",
+    "cli:dev": "cd cli && npm run dev"
   },
   "dependencies": {
     "@redocly/cli": "^1.34.5",