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Configurable client options v1.1.0 or later. See the Changelog before upgrading.

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Initialize the client

Your Blnk client is the single entry point to everything: ledgers, balances, transactions, webhooks, and more. Configure it once when your app starts, then use it everywhere.
blnk.ts
import { BlnkInit } from '@blnkfinance/blnk-typescript';

export const blnk = BlnkInit(process.env.BLNK_API_KEY ?? '', {
  baseUrl: process.env.BLNK_BASE_URL ?? 'http://localhost:5001',
});
That’s it. One import, one call, one client. From here you can create ledgers, move money, reconcile transactions, and manage your entire financial infrastructure.
create-ledger.ts
import { blnk } from './blnk';

const response = await blnk.Ledgers.create({
  name: 'Customer Savings Account',
  meta_data: {
    project_owner: 'YOUR_APP_NAME',
  },
});

console.log('Ledger Created:', response.data);

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Authentication

BlnkInit takes two arguments: an API key and a client options object. The options object must include baseUrl, the root URL of your Blnk Core instance. The SDK sends the API key on every request in the X-Blnk-Key header. How you set the API key depends on whether Core runs in secure mode:
When server.secure is enabled, pass your API key as the first argument. Set baseUrl to the URL where Core is reachable.
import { BlnkInit } from '@blnkfinance/blnk-typescript';

export const blnk = BlnkInit(process.env.BLNK_API_KEY ?? '', {
  baseUrl: process.env.BLNK_BASE_URL ?? 'http://localhost:5001',
});

Secure Blnk

Secure mode, master key, and server hardening.

Scoped API keys

Owner-scoped keys and permission limits.

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Timeouts and retries

When connections fail, Core restarts, or requests hang, the SDK safely handles it without blocking your app. To configure, pass the following parameters in the second options object: 
const blnk = BlnkInit(process.env.BLNK_API_KEY ?? '', {
  baseUrl: process.env.BLNK_BASE_URL ?? 'http://localhost:5001',
  timeout: 30000,
  retryCount: 3,
  retryDelayMs: 2000,
});
OptionTypeDefaultWhat it does for you
timeoutnumber10000How long to wait before giving up on a request. Bump this for slow operations like bulk reconciliations.
retryCountnumber1How many times to try. 1 means one attempt, no retries. 3 means try up to 3 times.
retryDelayMsnumber2000How long to wait between retries. Uses linear backoff, so the delay is predictable.
When to tune these:
  • Keep defaults if you’re making fast, local calls and want to fail fast.
  • Increase timeout if you’re running large batch requests that may take a while to complete synchronously.
  • Increase retryCount if you’re reading data across an unreliable network

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Custom logger

By default, the SDK logs its internal events through a built-in logger that writes to console with INFO:, ERROR:, and DEBUG: prefixes. Pass a custom logger to route these messages to your own logging system instead of console. 
const blnk = BlnkInit(apiKey, {
  baseUrl: 'http://localhost:5001',
  logger: {
    info: (message, ...meta) => appLogger.info({ meta }, message),
    error: (message, ...meta) => appLogger.error({ meta }, message),
  },
});
Metadata passed to the logger is redacted. The SDK strips values for keys such as api_key, authorization, token, and secret before logging.
LevelWhen the SDK calls it
infoBefore a retry, or when a retryable GET failure will be retried
errorWhen a request times out, returns a non-retryable HTTP error, or fails with a network error
Example logs
INFO: Retrying request to transactions/txn_f482a1b3-6c2d-4e89-a17b-3d5e8f2a1c94 { attempt: 2, maxAttempts: 3, delayMs: 2000 }

ERROR: Request timed out { endpoint: 'transactions/txn_f482a1b3-6c2d-4e89-a17b-3d5e8f2a1c94', timeoutMs: 30000 }

ERROR: Request to transactions/txn_f482a1b3-6c2d-4e89-a17b-3d5e8f2a1c94 failed with status 404.

Quick start

Install the SDK and create your first transaction.

Error handling

ApiResponse checks and Core error codes.

Changelog

TypeScript SDK releases and version history.

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Need help?

We are very happy to help you make the most of Blnk, regardless of whether it is your first time or you are switching from another tool. To ask questions or discuss issues, please contact us or join our Discord community.