/pressure API

The /pressure API returns real-time system load information for your Browserless instance, and is available for both self-hosted and dedicated accounts.

Querying system pressure

Issue a GET request to /pressure to check current load:

cURL

curl -X GET \
  https://production-sfo.browserless.io/pressure?token=YOUR_API_TOKEN_HERE

Javascript

const TOKEN = "YOUR_API_TOKEN_HERE";
const url = `https://production-sfo.browserless.io/pressure?token=${TOKEN}`;

const fetchPressure = async () => {
  const response = await fetch(url, {
    method: 'GET'
  });

  const result = await response.json();
  console.log(result);
};

fetchPressure();

Python

import requests

TOKEN = "YOUR_API_TOKEN_HERE"
url = f"https://production-sfo.browserless.io/pressure?token={TOKEN}"

response = requests.get(url)
result = response.json()

print(result)

Java

import java.io.*;
import java.net.URI;
import java.net.http.*;

public class FetchPressure {
    public static void main(String[] args) {
        String TOKEN = "YOUR_API_TOKEN_HERE";
        String url = "https://production-sfo.browserless.io/pressure?token=" + TOKEN;

        HttpClient client = HttpClient.newHttpClient();

        HttpRequest request = HttpRequest.newBuilder()
            .uri(URI.create(url))
            .GET()
            .build();

        try {
            HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
            System.out.println("Response: " + response.body());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

C#

using System;
using System.Net.Http;
using System.Threading.Tasks;

class Program {
    static async Task Main(string[] args) {
        string TOKEN = "YOUR_API_TOKEN_HERE";
        string url = $"https://production-sfo.browserless.io/pressure?token={TOKEN}";

        using var client = new HttpClient();

        try {
            var response = await client.GetAsync(url);
            response.EnsureSuccessStatusCode();

            var result = await response.Content.ReadAsStringAsync();
            Console.WriteLine("Response: " + result);
        } catch (Exception ex) {
            Console.WriteLine($"Error: {ex.Message}");
        }
    }
}

Running this request will result in a JSON output like:

{
  "pressure": {
    "cpu": 45,
    "memory": 62,
    "isAvailable": true,
    "maxConcurrent": 10,
    "maxQueued": 10,
    "running": 3,
    "queued": 0,
    "reason": "",
    "recentlyRejected": 0,
    "date": 1711468800000,
    "message": ""
  }
}

Response fields

Field	Type	Description
cpu	number or null	CPU usage percentage
memory	number or null	Memory usage percentage
isAvailable	boolean	Whether the instance accepts new sessions
maxConcurrent	number	Maximum concurrent browser sessions
maxQueued	number	Maximum queued requests
running	number	Currently running sessions
queued	number	Currently queued requests
reason	string	Why the instance is unavailable: full, cpu, memory, or empty
recentlyRejected	number	Recent rejected connection count
date	number	Timestamp of the response in milliseconds
message	string	Additional status message

Common use cases

Use /pressure to check whether your instance can handle another connection before starting a new session. This is especially useful for:

• Load balancing: Route traffic to instances with available capacity (see NGINX Load Balancing)
• Auto-scaling: Trigger scale-up when isAvailable is false or running approaches maxConcurrent
• Health monitoring: Integrate with external monitoring systems to track resource usage over time
• Queue management: Check queued count to detect when requests are backing up