Longbridge OpenAPI SDK for C

May 9, 2026 · View on GitHub

longbridge provides an easy-to-use interface for invoking Longbridge OpenAPI.

Context Types

Context	Description
`QuoteContext`	Real-time quotes, candlesticks, options, warrants, watchlists, push subscriptions
`TradeContext`	Orders, positions, account balance, executions, cash flow
`AssetContext`	Account statement download
`ContentContext`	News, community topics
`FundamentalContext`	Financial reports, analyst ratings, dividends, valuation, company overview, shareholders
`MarketContext`	Market status, broker holdings, A/H premium, trade statistics, anomaly alerts, index constituents
`CalendarContext`	Financial calendar (earnings, dividends, splits, IPOs, macro data, market closures)
`PortfolioContext`	Exchange rates, portfolio P&L analysis
`AlertContext`	Price alert management (add/enable/disable/delete)
`DCAContext`	Dollar-cost averaging plan management
`SharelistContext`	Community sharelist management

Documentation

SDK docs: https://longbridge.github.io/openapi/c/index.html
Longbridge OpenAPI: https://open.longbridge.com/en/

Examples

Runnable examples live in examples/c/:

examples/c/account_asset/main.c
examples/c/get_quote/main.c
examples/c/http_client/main.c
examples/c/subscribe_quote/main.c
examples/c/submit_order/main.c
examples/c/today_orders/main.c

Quickstart

Install Longbridge OpenAPI SDK

Download C SDK

Authentication

Longbridge OpenAPI supports two authentication methods:

1. OAuth 2.0 (Recommended)

OAuth 2.0 is the modern authentication method that uses Bearer tokens without requiring HMAC signatures.

Step 1: Register OAuth Client

First, register an OAuth client to get your client_id:

bash / macOS / Linux

curl -X POST https://openapi.longbridge.com/oauth2/register \
  -H "Content-Type: application/json" \
  -d '{
    "client_name": "My Application",
    "redirect_uris": ["http://localhost:60355/callback"],
    "grant_types": ["authorization_code", "refresh_token"]
  }'

PowerShell (Windows)

Invoke-RestMethod -Method Post -Uri https://openapi.longbridge.com/oauth2/register `
  -ContentType "application/json" `
  -Body '{
    "client_name": "My Application",
    "redirect_uris": ["http://localhost:60355/callback"],
    "grant_types": ["authorization_code", "refresh_token"]
  }'

Response:

{
  "client_id": "your-client-id-here",
  "client_secret": null,
  "client_name": "My Application",
  "redirect_uris": ["http://localhost:60355/callback"]
}

Save the client_id for use in your application.

Step 2: Build OAuth client and create a Config

lb_oauth_new loads a cached token from ~/.longbridge/openapi/tokens/<client_id> (%USERPROFILE%\.longbridge\openapi\tokens\<client_id> on Windows) if one exists and is still valid, or starts the browser authorization flow automatically. The token is persisted to the same path after a successful authorization or refresh. The resulting lb_oauth_t* handle is passed directly to lb_config_from_oauth.

#include <longbridge.h>
#include <stdio.h>

static void
on_open_url(const char* url, void* userdata)
{
  printf("Open this URL to authorize: %s\n", url);
}

static void
on_oauth_ready(const struct lb_async_result_t* res)
{
  if (res->error) {
    printf("OAuth failed: %s\n", lb_error_message(res->error));
    return;
  }

  lb_oauth_t* oauth = (lb_oauth_t*)res->data;
  lb_config_t* config = lb_config_from_oauth(oauth);
  // Use config to create contexts...
  lb_config_free(config);
  lb_oauth_free(oauth);
}

int
main(int argc, char const* argv[])
{
  lb_oauth_new("your-client-id", 0, on_open_url, NULL, on_oauth_ready, NULL);
  getchar();
  return 0;
}

2. Legacy API Key (Environment Variables)

Setting environment variables(MacOS/Linux)

export LONGBRIDGE_APP_KEY="App Key get from user center"
export LONGBRIDGE_APP_SECRET="App Secret get from user center"
export LONGBRIDGE_ACCESS_TOKEN="Access Token get from user center"

Setting environment variables(Windows)

setx LONGBRIDGE_APP_KEY "App Key get from user center"
setx LONGBRIDGE_APP_SECRET "App Secret get from user center"
setx LONGBRIDGE_ACCESS_TOKEN "Access Token get from user center"

Other environment variables

Name	Description
LONGBRIDGE_LANGUAGE	Language identifier, `zh-CN`, `zh-HK` or `en` (Default: `en`)
LONGBRIDGE_HTTP_URL	HTTP endpoint url (Default: `https://openapi.longbridge.com`)
LONGBRIDGE_QUOTE_WS_URL	Quote websocket endpoint url (Default: `wss://openapi-quote.longbridge.com/v2`)
LONGBRIDGE_TRADE_WS_URL	Trade websocket endpoint url (Default: `wss://openapi-trade.longbridge.com/v2`)
LONGBRIDGE_ENABLE_OVERNIGHT	Enable overnight quote, `true` or `false` (Default: `false`)
LONGBRIDGE_PUSH_CANDLESTICK_MODE	`realtime` or `confirmed` (Default: `realtime`)
LONGBRIDGE_PRINT_QUOTE_PACKAGES	Print quote packages when connected, `true` or `false` (Default: `true`)
LONGBRIDGE_LOG_PATH	Set the path of the log files (Default: `no logs`)

Quote API (Get basic information of securities)

#include <longbridge.h>
#include <stdio.h>
#ifdef WIN32
#include <windows.h>
#endif

static void
on_quote(const struct lb_async_result_t* res)
{
  if (res->error) {
    printf("failed to get quote: %s\n", lb_error_message(res->error));
    return;
  }

  lb_security_quote_t* data = (lb_security_quote_t*)res->data;
  for (int i = 0; i < res->length; i++) {
    const lb_security_quote_t* quote = &data[i];
    printf("%s timestamp=%lld last_done=%f open=%f high=%f low=%f volume=%lld "
           "turnover=%f\n",
           quote->symbol,
           quote->timestamp,
           lb_decimal_to_double(quote->last_done),
           lb_decimal_to_double(quote->open),
           lb_decimal_to_double(quote->high),
           lb_decimal_to_double(quote->low),
           quote->volume,
           lb_decimal_to_double(quote->turnover));
  }
}

static void
on_oauth_ready(const struct lb_async_result_t* res)
{
  if (res->error) {
    printf("OAuth failed: %s\n", lb_error_message(res->error));
    return;
  }

  lb_oauth_t* oauth = (lb_oauth_t*)res->data;
  lb_config_t* config = lb_config_from_oauth(oauth);
  const lb_quote_context_t* ctx = lb_quote_context_new(config);
  lb_config_free(config);
  lb_oauth_free(oauth);

  const char* symbols[] = { "700.HK", "AAPL.US", "TSLA.US", "NFLX.US" };
  lb_quote_context_quote(ctx, symbols, 4, on_quote, NULL);
}

static void
on_open_url(const char* url, void* userdata)
{
  printf("Open this URL to authorize: %s\n", url);
}

int
main(int argc, char const* argv[])
{
#ifdef WIN32
  SetConsoleOutputCP(CP_UTF8);
#endif

  lb_oauth_new("your-client-id", 0, on_open_url, NULL, on_oauth_ready, NULL);
  getchar();
  return 0;
}

#include <longbridge.h>
#include <stdio.h>
#ifdef WIN32
#include <windows.h>
#endif

static void
on_quote(const struct lb_quote_context_t* ctx,
         const struct lb_push_quote_t* quote,
         void* userdata)
{
  printf("%s timestamp=%lld last_done=%f open=%f high=%f low=%f volume=%lld "
         "turnover=%f\n",
         quote->symbol,
         quote->timestamp,
         lb_decimal_to_double(quote->last_done),
         lb_decimal_to_double(quote->open),
         lb_decimal_to_double(quote->high),
         lb_decimal_to_double(quote->low),
         quote->volume,
         lb_decimal_to_double(quote->turnover));
}

static void
on_subscribe(const struct lb_async_result_t* res)
{
  if (res->error) {
    printf("failed to subscribe: %s\n", lb_error_message(res->error));
  }
}

static void
on_oauth_ready(const struct lb_async_result_t* res)
{
  if (res->error) {
    printf("OAuth failed: %s\n", lb_error_message(res->error));
    return;
  }

  lb_oauth_t* oauth = (lb_oauth_t*)res->data;
  lb_config_t* config = lb_config_from_oauth(oauth);
  const lb_quote_context_t* ctx = lb_quote_context_new(config);
  lb_config_free(config);
  lb_oauth_free(oauth);

  lb_quote_context_set_on_quote(ctx, on_quote, NULL, NULL);

  const char* symbols[] = { "700.HK", "AAPL.US", "TSLA.US", "NFLX.US" };
  lb_quote_context_subscribe(ctx, symbols, 4, LB_SUBFLAGS_QUOTE, on_subscribe, NULL);
}

static void
on_open_url(const char* url, void* userdata)
{
  printf("Open this URL to authorize: %s\n", url);
}

int
main(int argc, char const* argv[])
{
#ifdef WIN32
  SetConsoleOutputCP(CP_UTF8);
#endif

  lb_oauth_new("your-client-id", 0, on_open_url, NULL, on_oauth_ready, NULL);
  getchar();
  return 0;
}

Trade API (Submit order)

#include <longbridge.h>
#include <stdio.h>
#ifdef WIN32
#include <windows.h>
#endif

static void
on_submit_order(const struct lb_async_result_t* res)
{
  if (res->error) {
    printf("failed to submit order: %s\n", lb_error_message(res->error));
    return;
  }

  const lb_submit_order_response_t* resp = res->data;
  printf("order id: %s\n", resp->order_id);
}

static void
on_oauth_ready(const struct lb_async_result_t* res)
{
  if (res->error) {
    printf("OAuth failed: %s\n", lb_error_message(res->error));
    return;
  }

  lb_oauth_t* oauth = (lb_oauth_t*)res->data;
  lb_config_t* config = lb_config_from_oauth(oauth);
  const lb_trade_context_t* ctx = lb_trade_context_new(config);
  lb_config_free(config);
  lb_oauth_free(oauth);

  lb_decimal_t* submitted_price = lb_decimal_from_double(50.0);
  lb_decimal_t* submitted_quantity = lb_decimal_from_double(200.0);
  lb_submit_order_options_t opts = {
    "700.HK",       OrderTypeLO,
    OrderSideBuy,   submitted_quantity,
    TimeInForceDay, submitted_price,
    NULL,           NULL,
    NULL,           NULL,
    NULL,           NULL,
    NULL,
  };
  lb_decimal_free(submitted_price);
  lb_decimal_free(submitted_quantity);
  lb_trade_context_submit_order(ctx, &opts, on_submit_order, NULL);
}

static void
on_open_url(const char* url, void* userdata)
{
  printf("Open this URL to authorize: %s\n", url);
}

int
main(int argc, char const* argv[])
{
#ifdef WIN32
  SetConsoleOutputCP(CP_UTF8);
#endif

  lb_oauth_new("your-client-id", 0, on_open_url, NULL, on_oauth_ready, NULL);
  getchar();
  return 0;
}

Troubleshooting

Windows setx requires a new terminal; use set for the current cmd.exe session.
If you don't see callbacks, keep the process alive (examples use getchar()).
If building on Linux/macOS, ensure ncurses is installed (examples link it on non-Windows).
For debugging, set LONGBRIDGE_LOG_PATH to enable SDK logs.

License

Licensed under either of

Apache License, Version 2.0,(LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT) at your option.