TypeScript SDK - Fingo Pay

This library provides convenient access to the Fingo Pay REST API from server-side TypeScript or JavaScript. It is generated with Stainless.

Installation

Install the Fingo Pay TypeScript SDK using your preferred package manager:

npm
pnpm
yarn
bun

npm install @fingoafrica/fingo-pay

pnpm add @fingoafrica/fingo-pay

yarn add @fingoafrica/fingo-pay

bun add @fingoafrica/fingo-pay

Quick start

Initialize the SDK with your API key and make your first request:

import FingoPay from '@fingoafrica/fingo-pay';

const client = new FingoPay({
  apiKey: process.env['FINGO_PAY_API_KEY'], // This is the default and can be omitted
});

const acceptedResponse = await client.mpesa.createCharge({
  amount: 150000,
  merchantTransactionId: 'invoice_48291',
  phoneNumber: '+254712345678',
});

console.log(acceptedResponse.data);

Never expose your secret API key in client-side code or version control. Use environment variables.

Request & response types

This library includes TypeScript definitions for all request params and response fields. Import and use them for full type safety:

import FingoPay from '@fingoafrica/fingo-pay';

const client = new FingoPay({
  apiKey: process.env['FINGO_PAY_API_KEY'],
});

const params: FingoPay.MpesaCreateChargeParams = {
  amount: 150000,
  merchantTransactionId: 'invoice_48291',
  phoneNumber: '+254712345678',
};

const acceptedResponse: FingoPay.AcceptedResponse = await client.mpesa.createCharge(params);

Documentation for each method, request param, and response field are available in docstrings and will appear on hover in most modern editors.

Handling errors

When the library is unable to connect to the API, or if the API returns a non-success status code (i.e., 4xx or 5xx response), a subclass of APIError will be thrown:

const acceptedResponse = await client.mpesa
  .createCharge({
    amount: 150000,
    merchantTransactionId: 'invoice_48291',
    phoneNumber: '+254712345678',
  })
  .catch(async (err) => {
    if (err instanceof FingoPay.APIError) {
      console.log(err.status); // 400
      console.log(err.name); // BadRequestError
      console.log(err.headers); // {server: 'nginx', ...}
    } else {
      throw err;
    }
  });

Error codes

Status Code	Error Type
400	`BadRequestError`
401	`AuthenticationError`
403	`PermissionDeniedError`
404	`NotFoundError`
422	`UnprocessableEntityError`
429	`RateLimitError`
>=500	`InternalServerError`
N/A	`APIConnectionError`

Retries

Certain errors are automatically retried 2 times by default, with a short exponential backoff. The following errors are retried:

Connection errors (e.g., network connectivity problems)
408 Request Timeout
409 Conflict
429 Rate Limit
=500 Internal errors

Configure or disable retries using the maxRetries option:

// Configure the default for all requests:
const client = new FingoPay({
  maxRetries: 0, // default is 2
});

// Or, configure per-request:
await client.mpesa.createCharge(
  {
    amount: 150000,
    merchantTransactionId: 'invoice_48291',
    phoneNumber: '+254712345678',
  },
  {
    maxRetries: 5,
  }
);

Timeouts

Requests time out after 1 minute by default. Configure this with the timeout option:

// Configure the default for all requests:
const client = new FingoPay({
  timeout: 20 * 1000, // 20 seconds (default is 1 minute)
});

// Override per-request:
await client.mpesa.createCharge(
  {
    amount: 150000,
    merchantTransactionId: 'invoice_48291',
    phoneNumber: '+254712345678',
  },
  {
    timeout: 5 * 1000,
  }
);

On timeout, an APIConnectionTimeoutError is thrown. Requests that time out will be retried twice by default.

Advanced usage

Accessing raw response data

The “raw” Response returned by fetch() can be accessed through the .asResponse() method on the APIPromise type. This method returns as soon as the headers for a successful response are received and does not consume the response body, allowing custom parsing or streaming logic. Use .withResponse() to get the raw Response along with the parsed data:

const client = new FingoPay();

// Access raw response without consuming body
const response = await client.mpesa
  .createCharge({
    amount: 150000,
    merchantTransactionId: 'invoice_48291',
    phoneNumber: '+254712345678',
  })
  .asResponse();

console.log(response.headers.get('X-My-Header'));
console.log(response.statusText);

// Get both parsed data and raw response
const { data: acceptedResponse, response: raw } = await client.mpesa
  .createCharge({
    amount: 150000,
    merchantTransactionId: 'invoice_48291',
    phoneNumber: '+254712345678',
  })
  .withResponse();

console.log(raw.headers.get('X-My-Header'));
console.log(acceptedResponse.data);

Logging

All log messages are intended for debugging only. The format and content of log messages may change between releases.

Log levels

Configure the log level in two ways:

Via the FINGO_PAY_LOG environment variable
Using the logLevel client option (overrides the environment variable)

import FingoPay from '@fingoafrica/fingo-pay';

const client = new FingoPay({
  logLevel: 'debug', // Show all log messages
});

Available log levels, from most to least verbose:

Level	Description
`debug`	Show debug messages, info, warnings, and errors
`info`	Show info messages, warnings, and errors
`warn`	Show warnings and errors (default)
`error`	Show only errors
`off`	Disable all logging

At the debug level, all HTTP requests and responses are logged, including headers and bodies. Some authentication-related headers are redacted, but sensitive data in request and response bodies may still be visible.

Custom logger

Provide a custom logger instead of the default globalThis.console. Most logging libraries are supported, including pino, winston, bunyan, consola, signale, and @std/log.

import FingoPay from '@fingoafrica/fingo-pay';
import pino from 'pino';

const logger = pino();

const client = new FingoPay({
  logger: logger.child({ name: 'FingoPay' }),
  logLevel: 'debug',
});

Making custom/undocumented requests

Undocumented endpoints

Make requests to undocumented endpoints using client.get, client.post, and other HTTP verbs:

await client.post('/some/path', {
  body: { some_prop: 'foo' },
  query: { some_query_arg: 'bar' },
});

Undocumented request params

Use // @ts-expect-error for undocumented parameters:

client.mpesa.createCharge({
  amount: 150000,
  merchantTransactionId: 'invoice_48291',
  phoneNumber: '+254712345678',
  // @ts-expect-error baz is not yet public
  baz: 'undocumented option',
});

Customizing the fetch client

By default, this library expects a global fetch function. You can polyfill it globally or pass a custom one:

import FingoPay from '@fingoafrica/fingo-pay';
import fetch from 'my-fetch';

const client = new FingoPay({ fetch });

Fetch options

Provide custom fetch options when instantiating the client or making a request:

import FingoPay from '@fingoafrica/fingo-pay';

const client = new FingoPay({
  fetchOptions: {
    // `RequestInit` options
  },
});

Configuring proxies

Provide custom fetchOptions to add runtime-specific proxy options:

Node.js
Bun
Deno

import FingoPay from '@fingoafrica/fingo-pay';
import * as undici from 'undici';

const proxyAgent = new undici.ProxyAgent('http://localhost:8888');
const client = new FingoPay({
  fetchOptions: {
    dispatcher: proxyAgent,
  },
});

import FingoPay from '@fingoafrica/fingo-pay';

const client = new FingoPay({
  fetchOptions: {
    proxy: 'http://localhost:8888',
  },
});

import FingoPay from 'npm:@fingoafrica/fingo-pay';

const httpClient = Deno.createHttpClient({
  proxy: { url: 'http://localhost:8888' },
});

const client = new FingoPay({
  fetchOptions: {
    client: httpClient,
  },
});

Requirements

TypeScript >= 4.9 is supported.

The following runtimes are supported:

Runtime	Version
Web browsers	Up-to-date Chrome, Firefox, Safari, Edge, and more
Node.js	20 LTS or later (non-EOL) versions
Deno	v1.28.0 or higher
Bun	1.0 or later
Cloudflare Workers	Latest
Vercel Edge Runtime	Latest
Jest	28 or greater with the “node” environment
Nitro	v2.6 or greater

React Native is not supported at this time. The jsdom environment in Jest is also not supported.

Semantic versioning

This package generally follows SemVer conventions, though certain backwards-incompatible changes may be released as minor versions:

Changes that only affect static types, without breaking runtime behavior
Changes to library internals which are technically public but not intended or documented for external use
Changes that we do not expect to impact the vast majority of users in practice

SDK Source Code

View the SDK source code and contribute on GitHub

npm Package

View the package on npm

Official SDKs

​Installation

​Quick start

​Request & response types

​Handling errors

​Error codes

​Retries

​Timeouts

​Advanced usage

​Accessing raw response data

​Logging

​Log levels

​Custom logger

​Making custom/undocumented requests

​Undocumented endpoints

​Undocumented request params

​Customizing the fetch client

​Fetch options

​Configuring proxies

​Requirements

​Semantic versioning

SDK Source Code

npm Package

Installation

Quick start

Request & response types

Handling errors

Error codes

Retries

Timeouts

Advanced usage

Accessing raw response data

Logging

Log levels

Custom logger

Making custom/undocumented requests

Undocumented endpoints

Undocumented request params

Customizing the fetch client

Fetch options

Configuring proxies

Requirements

Semantic versioning