PeekAPI — Node.js SDK

Zero-dependency Node.js SDK for PeekAPI. Add API analytics to any Node.js framework with one line of middleware.

Install

npm install @peekapi/sdk-node

Quick Start

Express

import express from "express";
import { peekapi } from "@peekapi/sdk-node";

const app = express();
app.use(peekapi({ apiKey: "ak_live_xxx" }));

app.get("/api/users", (req, res) => res.json({ users: [] }));
app.listen(3000);

Fastify

import Fastify from "fastify";
import { peekapiFastify } from "@peekapi/sdk-node";

const app = Fastify();
app.register(peekapiFastify, { apiKey: "ak_live_xxx" });

app.get("/api/users", async () => ({ users: [] }));
app.listen({ port: 3000 });

Koa

import Koa from "koa";
import { peekapiKoa } from "@peekapi/sdk-node";

const app = new Koa();
app.use(peekapiKoa({ apiKey: "ak_live_xxx" }));

app.use((ctx) => { ctx.body = { users: [] }; });
app.listen(3000);

Hapi

import Hapi from "@hapi/hapi";
import { peekapiHapi } from "@peekapi/sdk-node";

const server = Hapi.server({ port: 3000 });
await server.register({ plugin: peekapiHapi, options: { apiKey: "ak_live_xxx" } });

server.route({ method: "GET", path: "/api/users", handler: () => ({ users: [] }) });
await server.start();

NestJS

import { Module } from "@nestjs/common";
import { APP_INTERCEPTOR } from "@nestjs/core";
import { PeekApiInterceptor } from "@peekapi/sdk-node";

@Module({
  providers: [
    {
      provide: APP_INTERCEPTOR,
      useFactory: () => new PeekApiInterceptor({ apiKey: "ak_live_xxx" }),
    },
  ],
})
export class AppModule {}

Standalone Client

import { PeekApiClient } from "@peekapi/sdk-node";

const client = new PeekApiClient({ apiKey: "ak_live_xxx" });

client.track({
  method: "GET",
  path: "/api/users",
  status_code: 200,
  response_time_ms: 42,
});

// Graceful shutdown (flushes remaining events)
client.shutdown();

Configuration

Option	Default	Description
apiKey	required	Your PeekAPI key
endpoint	PeekAPI cloud	Ingestion endpoint URL
flushInterval	10000	Milliseconds between automatic flushes
batchSize	100	Events per HTTP POST (triggers flush)
maxBufferSize	10000	Max events held in memory
maxStorageBytes	5242880	Max disk fallback file size (5MB)
maxEventBytes	65536	Per-event size limit (64KB)
storagePath	auto	Custom path for JSONL persistence file
debug	false	Enable debug logging
identifyConsumer	auto	Custom consumer ID extraction function
tlsOptions	undefined	TLS options for https.Agent
onError	undefined	Callback for background flush errors

How It Works

1. Middleware intercepts every request/response
2. Captures method, path, status code, response time, request/response sizes, consumer ID
3. Events are buffered in memory and flushed in batches on a timer or when batchSize is reached
4. Flushes are async and non-blocking — <1ms overhead per request
5. On network failure: exponential backoff with jitter, up to 5 retries
6. After max retries: events are persisted to a JSONL file on disk
7. On next startup: persisted events are recovered and re-sent
8. On SIGTERM/SIGINT: remaining buffer is flushed or persisted to disk

Consumer Identification

By default, consumers are identified by:

1. X-API-Key header — stored as-is
2. Authorization header — hashed with SHA-256 (stored as hash_<hex>)

Override with the identifyConsumer option to use any header or request property:

app.use(peekapi({
  apiKey: "ak_live_xxx",
  identifyConsumer: (req) => req.headers["x-tenant-id"],
}));

What Gets Tracked

Field	Description
method	HTTP method (GET, POST, etc.)
path	Route path (no query strings)
status_code	Response status code
response_time_ms	Time to respond in ms
request_size	Request body size in bytes
response_size	Response body size in bytes
consumer_id	API consumer identifier
timestamp	ISO 8601 timestamp

Requirements

• Node.js >= 18

Contributing

Bug reports and feature requests: peekapi-dev/community

1. Fork & clone the repo
2. Install dependencies — npm install
3. Run tests — npm test
4. Submit a PR

Support

If you find PeekAPI useful, give this repo a star — it helps others discover the project.

Badge

Show that your API is monitored by PeekAPI:

[![Monitored by PeekAPI](https://img.shields.io/badge/monitored%20by-PeekAPI-06b6d4)](https://peekapi.dev)

License

MIT