diff --git a/intelligence_finance_v1_ga/client.go b/intelligence_finance_v1_ga/client.go
new file mode 100644
index 0000000..83a2b1b
--- /dev/null
+++ b/intelligence_finance_v1_ga/client.go
@@ -0,0 +1,237 @@
+package intelligence_finance_v1_ga
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+)
+
+// 默认接口路径（实际路径以接口对接时分配的短码为准，可通过 Option 覆盖）。
+const (
+	DefaultInvoiceOrderPath       = "/invoice/order"
+	DefaultQueryInvoiceStatusPath = "/invoice/status/query"
+	DefaultCreatePaymentPath      = "/payment/create"
+	DefaultQueryPaymentStatusPath = "/payment/status/query"
+)
+
+// Client 是业财连接接口的客户端。
+type Client struct {
+	baseURL      string
+	tenantID     string
+	clientID     string
+	clientSecret string
+	httpClient   *http.Client
+	signEnabled  bool
+
+	invoiceOrderPath       string
+	queryInvoiceStatusPath string
+	createPaymentPath      string
+	queryPaymentStatusPath string
+}
+
+// Option 定义客户端配置选项。
+type Option func(*Client)
+
+// WithHTTPClient 设置自定义 HTTP 客户端。
+func WithHTTPClient(c *http.Client) Option {
+	return func(cli *Client) {
+		cli.httpClient = c
+	}
+}
+
+// WithTimeout 设置请求超时时间。
+func WithTimeout(d time.Duration) Option {
+	return func(cli *Client) {
+		cli.httpClient.Timeout = d
+	}
+}
+
+// WithSignEnabled 设置是否启用签名。
+// 客户应用需启用签名（默认启用）；钉钉AI表格无需配置签名，可设置为 false。
+func WithSignEnabled(enabled bool) Option {
+	return func(cli *Client) {
+		cli.signEnabled = enabled
+	}
+}
+
+// WithInvoiceOrderPath 覆盖订单开票接口路径。
+func WithInvoiceOrderPath(p string) Option {
+	return func(cli *Client) { cli.invoiceOrderPath = p }
+}
+
+// WithQueryInvoiceStatusPath 覆盖开票状态查询接口路径。
+func WithQueryInvoiceStatusPath(p string) Option {
+	return func(cli *Client) { cli.queryInvoiceStatusPath = p }
+}
+
+// WithCreatePaymentPath 覆盖创建付款单据接口路径。
+func WithCreatePaymentPath(p string) Option {
+	return func(cli *Client) { cli.createPaymentPath = p }
+}
+
+// WithQueryPaymentStatusPath 覆盖支付状态查询接口路径。
+func WithQueryPaymentStatusPath(p string) Option {
+	return func(cli *Client) { cli.queryPaymentStatusPath = p }
+}
+
+// NewClient 创建一个新的业财连接接口客户端。
+// baseURL 为平台接口地址，tenantID 为平台分配的租户唯一标识，
+// clientID 为平台分配的应用标识（钉钉AI表格固定为 "dd-ai-table"），
+// clientSecret 为平台分配的密钥。
+func NewClient(baseURL, tenantID, clientID, clientSecret string, opts ...Option) *Client {
+	c := &Client{
+		baseURL:                strings.TrimRight(baseURL, "/"),
+		tenantID:               tenantID,
+		clientID:               clientID,
+		clientSecret:           clientSecret,
+		httpClient:             &http.Client{Timeout: 30 * time.Second},
+		signEnabled:            true,
+		invoiceOrderPath:       DefaultInvoiceOrderPath,
+		queryInvoiceStatusPath: DefaultQueryInvoiceStatusPath,
+		createPaymentPath:      DefaultCreatePaymentPath,
+		queryPaymentStatusPath: DefaultQueryPaymentStatusPath,
+	}
+	for _, opt := range opts {
+		opt(c)
+	}
+	return c
+}
+
+// doRequest 发送 POST 请求并处理通用响应结构，返回 data 字段的原始字节。
+func (c *Client) doRequest(ctx context.Context, path string, reqBody interface{}) (json.RawMessage, error) {
+	bodyBytes, err := json.Marshal(reqBody)
+	if err != nil {
+		return nil, &SDKError{Op: "doRequest", Err: fmt.Errorf("marshal request: %w", err)}
+	}
+
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.baseURL+path, bytes.NewReader(bodyBytes))
+	if err != nil {
+		return nil, &SDKError{Op: "doRequest", Err: fmt.Errorf("new request: %w", err)}
+	}
+
+	req.Header.Set("Content-Type", "application/json")
+	req.Header.Set("tenant-id", c.tenantID)
+	req.Header.Set("client-id", c.clientID)
+
+	if c.signEnabled {
+		timestamp := GenerateTimestamp()
+		nonce, err := GenerateNonce(16)
+		if err != nil {
+			return nil, &SDKError{Op: "doRequest", Err: fmt.Errorf("generate nonce: %w", err)}
+		}
+		// 签名算法：HmacSHA256，密钥为 client-secret，签名数据为 timestamp + nonce，结果 Base64 编码。
+		signature := HmacSHA256Base64(c.clientSecret, timestamp+nonce)
+		req.Header.Set("x-bfl-signature-timestamp", timestamp)
+		req.Header.Set("x-bfl-signature-nonce", nonce)
+		req.Header.Set("x-bfl-signature", signature)
+	}
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, &SDKError{Op: "doRequest", Err: fmt.Errorf("do request: %w", err)}
+	}
+	defer resp.Body.Close()
+
+	respBytes, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, &SDKError{Op: "doRequest", Err: fmt.Errorf("read response: %w", err)}
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, &APIError{HTTPStatus: resp.StatusCode, Body: string(respBytes)}
+	}
+
+	var base BaseResponse
+	if err := json.Unmarshal(respBytes, &base); err != nil {
+		return nil, &SDKError{Op: "doRequest", Err: fmt.Errorf("unmarshal base response: %w", err)}
+	}
+	if base.Code != 0 && base.Code != 200 {
+		return nil, &APIError{Code: base.Code, Msg: base.Msg}
+	}
+	return base.Data, nil
+}
+
+// InvoiceOrder 提交订单开票请求。
+func (c *Client) InvoiceOrder(ctx context.Context, req *InvoiceOrderRequest) (*InvoiceOrderData, error) {
+	data, err := c.doRequest(ctx, c.invoiceOrderPath, req)
+	if err != nil {
+		return nil, err
+	}
+	var out InvoiceOrderData
+	if len(data) > 0 {
+		if err := json.Unmarshal(data, &out); err != nil {
+			return nil, &SDKError{Op: "InvoiceOrder", Err: fmt.Errorf("unmarshal data: %w", err)}
+		}
+	}
+	return &out, nil
+}
+
+// QueryInvoiceStatus 查询订单开票状态。
+func (c *Client) QueryInvoiceStatus(ctx context.Context, req *QueryInvoiceStatusRequest) (*QueryInvoiceStatusData, error) {
+	data, err := c.doRequest(ctx, c.queryInvoiceStatusPath, req)
+	if err != nil {
+		return nil, err
+	}
+	var out QueryInvoiceStatusData
+	if len(data) > 0 {
+		if err := json.Unmarshal(data, &out); err != nil {
+			return nil, &SDKError{Op: "QueryInvoiceStatus", Err: fmt.Errorf("unmarshal data: %w", err)}
+		}
+	}
+	return &out, nil
+}
+
+// CreatePayment 创建付款单据。
+func (c *Client) CreatePayment(ctx context.Context, req *CreatePaymentRequest) (*CreatePaymentData, error) {
+	data, err := c.doRequest(ctx, c.createPaymentPath, req)
+	if err != nil {
+		return nil, err
+	}
+	var out CreatePaymentData
+	if len(data) > 0 {
+		if err := json.Unmarshal(data, &out); err != nil {
+			return nil, &SDKError{Op: "CreatePayment", Err: fmt.Errorf("unmarshal data: %w", err)}
+		}
+	}
+	return &out, nil
+}
+
+// QueryPaymentStatus 查询支付状态。
+// 响应数据与支付完成通知的数据结构一致。
+func (c *Client) QueryPaymentStatus(ctx context.Context, req *QueryPaymentStatusRequest) (*PaymentInfo, error) {
+	data, err := c.doRequest(ctx, c.queryPaymentStatusPath, req)
+	if err != nil {
+		return nil, err
+	}
+	var out PaymentInfo
+	if len(data) > 0 {
+		if err := json.Unmarshal(data, &out); err != nil {
+			return nil, &SDKError{Op: "QueryPaymentStatus", Err: fmt.Errorf("unmarshal data: %w", err)}
+		}
+	}
+	return &out, nil
+}
+
+// ParsePaymentNotify 解析支付完成通知请求体。
+// 该接口由客户提供、平台调用，用于在支付完成后接收平台回调。
+func ParsePaymentNotify(body []byte) (*PaymentInfo, error) {
+	var info PaymentInfo
+	if err := json.Unmarshal(body, &info); err != nil {
+		return nil, &SDKError{Op: "ParsePaymentNotify", Err: fmt.Errorf("unmarshal notify: %w", err)}
+	}
+	return &info, nil
+}
+
+// ParseNotify 解析通用通知请求体（bizType / bizId / data）。
+func ParseNotify(body []byte) (*NotifyRequest, error) {
+	var req NotifyRequest
+	if err := json.Unmarshal(body, &req); err != nil {
+		return nil, &SDKError{Op: "ParseNotify", Err: fmt.Errorf("unmarshal notify: %w", err)}
+	}
+	return &req, nil
+}
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