fm-sdk-typescript

TypeScript / JavaScript SDK for the Flexemarkets API.

⚠️ Alpha software — the API is not stable

fm-sdk is pre-1.0 and under active development. Anything public may be added, renamed, or removed in any release, including in ways that break code that compiles and runs today, and without a deprecation period first. Under semantic versioning a 0.x release carries no compatibility promise, and that is how these versions are used: treat every 0.x bump as potentially breaking.

Pin an exact version rather than a range ("@flexemarkets/fm-sdk": "0.2.0", not ^0.2.0), read the upgrade notes for the release you are moving to, and expect to change code when you move.

Not recommended for production use.

Requirements

• Node.js 22+ (ES modules)

Install

npm install @flexemarkets/fm-sdk

Configuration

The SDK loads credentials and endpoint from these sources (highest priority first):

1. Arguments passed to Flexemarkets.connect()
2. Files ~/.fm/credential and ~/.fm/endpoint (Java .properties format)
3. Environment variable FM_API_URL (defaults to https://api.flexemarkets.com)

Credential file

Create ~/.fm/credential:

account=myaccount
[email protected]
password=secret

Or use a bearer token:

token=eyJhbGciOiJIUzI1NiJ9...

Endpoint file

Create ~/.fm/endpoint:

endpoint=https://api.flexemarkets.com/api/marketplaces/123

SDK usage

import { Flexemarkets } from "@flexemarkets/fm-sdk";

// connect(null, null, ...) falls back to ~/.fm/credential and ~/.fm/endpoint
const fm = await Flexemarkets.connect(null, null, "my-bot");

// REST API
const marketplaceId = fm.endpointMarketplaceId;
const markets = await fm.markets(marketplaceId);
const session = await fm.session(marketplaceId);
const holding = await fm.holding(marketplaceId);

// Submit orders
const order = await fm.submitLimit(marketplaceId, markets[0].id, "BUY", 1, 950);
await fm.submitCancel(marketplaceId, markets[0].id, order.id);

// Live market data. A desk keeps the books and tapes for you: it seeds them
// over REST, applies deltas, and re-seeds after a sequence gap.
const desk = await fm.desk(marketplaceId);
const marketId = markets[0].id;

desk.onBookChange(marketId, (book) => console.log(book.bestPrice("BUY")));
desk.onSessionChange((s) => console.log(s.state));
desk.onHoldingChange((h) => console.log(h.cash));

const one = desk.book(marketId);          // one market
for (const book of desk.books()) {        // every market in the marketplace
  console.log(book.symbol, book.bestPrice("BUY"));
}

desk.close();

Example: ticker

The SDK includes a ticker example — a live terminal display of order book best bid/ask, spread, and recent trade prices.

npx tsx src/ticker.ts -C ~/.fm/credential -E 123

Options:

Output:

fm-ticker                                              OPEN

  Symbol     Bid     Ask  Spread   Last trades
  ------  ------  ------  ------   -----------
    AAPL    9.50   10.50    1.00   9.50  10.00
     IBM    4.00    5.00    1.00   4.50

The display refreshes on each order book update. Press Ctrl-C to stop.