Visa Appointment Tracker

This app does not automatically schedule appointments.

Available schedule dates for US Visa interviews may get very competetive. The waiting for new appointments can be terribly long like more than a year of waiting for the closer coming available date.

Scheduling dates become available due to different reasons such as people that give up or that reschedule their appointments. New available scheduling dates might not last more than a few minutes or hours depending on the region you're scheduling your US Visa interview.

How is this app useful?

This app is useful for you that already scheduled your US Visa interview but you'd like to change the appointment to a sooner date. This app is designed to track available scheduling dates of your preference. It watchs for scheduling dates that become available and notifies ASAP by making a call through the Twillio API.

This app isn't meant to automatically schedule or change appointments but only to notify when available dates according to your settings get vacant.

This is a hobby project that was born due to a need of finding a closer upcoming appointment date for my US Visa interview. I hope that it can help other people finding vacant dates according to their preferences as soon as they get available in the US System. — Dhyego Calota, Author

Important Disclosure

This app is not stable nor production-ready. It deeply relies on the Routing and HTML pages structure of the US Visa system. This app might break on noticeably changes made in the US Visa system.

We aren't constantly monitoring this app health.

Feel free to open an Issue in case of the app misbehave.

Prerequisites

1. Install Node >=18.0.0
2. Create a Twilio account with phone calls enabled
   • Notice that a Twilio's Free-trial plan tier may fulfill your needs
   • Twilio's Free-trial tier provides a Caller number and let you configure your existing phone number as the Receiver
3. Make sure to have access to your US Visa Info's account
4. Get the US Visa Info's Group ID [See]

How to Get US Visa Info's Group ID

1. Access the US Visa Info's system
2. Sign in
3. Click on the Group
4. Extract the Group ID from the URL

https://ais.usvisa-info.com/{location}/niv/schedule/{group-id}/continue_actions

For example, given the URL:

https://ais.usvisa-info.com/pt-br/niv/schedule/84746362/continue_actions

The Group ID is: 84746362

Setup

1. Complete Prerequisites
2. Create environment variables with the desired settings
3. You're good to start the app

Environment Variables

¹This env var name doesn't have space chars; We only used them to make it better distribute column sizes

Workflows

This app may have multiple Workflows with different goals and settings. Currently we support only one Workflow.

Take a look at the Features section if you're interested about how Workflows work.

Get Available Appointment Consulates

This Workflow searches for available scheduling dates according to your preferences on all facilities available in the country you scheduled your US Visa interview. It will call you through the Twilio API as soon as it finds an available date.

Settings

Yarn Commands

Deploying to Production

This app should be easy enough to deploy to any production environment that supports Node 18+ with environment variables.

Heroku

We encourage using Heroku to deploy this app due to the ease of just clicking in the deploy button below and making sure to configure the environment variables.

Notice that this app does not use a web dyno.

Troubleshootings

Soft Rate-limit Policy

The US Visa Info enforces a very tricky Rate-limiting system. There's no official documentation about their policy and all of the things described here are just assumptions or knowledge/experience somehow acquired through usage.

This rate-limiting system doesn't explicitly lock you out of their dashboard but instead they start to return empty lists in the place of the actual available scheduling dates. We call this behavior a soft-ban that may last up to 5 hours to reset.

How to avoid this soft-ban?

We strongly recommend the Get Available Appointment Consulates Workflow every 15 minutes or more so you don't get soft-banned in just a few hours.

How to know if get soft-banned?

Monitor your logs. You'll start constantly receiving a log line like this in different executions:

Consulate available dates list is empty. Did you get soft-banned?

What should I do after I get soft-banned?

In case that you get soft-banned, the only possible way to reset this quota is to shutdown the app and wait at least 5 hours until to start it again.

Features

This app leverages from some cool features that you may get interested of.

Logs

Logs are incredibly heplful to understand the execution state in real time especially because currently this app only supports terminal as its UI.

Environment Variables

Rather than hard-coding settings in the codebase, we use Environment Variables to configure this app. Environment Variables is one the 12 factors that guides to build better production-ready applications.

Scraping Process

The US Visa Info does not offer any kind of automated integrations like a Web API.

The need of watching available scheduling dates was greater than this lack of automations so we automated a scraping process using Puppeteer to interact with the US Visa Info as a human would.

Composability

This app widely uses the concept of composability to achieve its goals. Rather than writing a single large file with thousands of instruction lines, we implemented the concept of Workflows that may contain multiple Commands.

Each Workflow has a clear and single goal to achieve. We may split a Workflow into multiple Commands where each Command also has a clear and single small goal towards the Workflow's major goal.

Execution State

Workflows implement their own execution state which makes it so easy to track and debug their execution and progress in real time.

We leverage execution states to write logs to track progress of a Workflow and each one of its Commands.

Retryability

This app deeply rely on the uncertainty of Network requests and responses. Each Command is susceptible to failures which can be cascaded to the Workflow forcing the entire execution to exit early with an error.

Because of the soft rate-limiting implicitly imposed by the US system, we must set a reasonably interval time between executions so we avoid getting soft-banned. This reasonably interval time makes executions valuable enough to be wasted. We need to make sure to put all effort possible to successfully finish a Workflow execution. This is exactly why the retryability of each Command is so important in this app.

Auto-discovery

This app supports multiple Workflows and we leverage from a Workflow Registry to manage their lifecycle like registering and initialization. It enables clients to initialize Workflows without the need of knowing each one of them with line of codes as simple as:

const workflows = WorkflowRegistry.getOrInitialize().buildWorkflows({ config, logger });

workflows.forEach((workflow) => {
  workflow.start();
});

Typing

We use Typing through TypeScript which enables developers to quickly understand the API without the need of reading long documentation pages.

Contributions

This was a hobby project born out of real needs and there was no funding budget at all.

All kinds of contributions or constructive usage feedbacks are encouraged. Please feel free to create an Issue, or opening a Pull Request, or even to contribute answering someone else's Issues.

We'll do our best to review new Issues and Pull Requests ASAP.

Debug Mode

You can run this app in Debug Mode in your local machine.

1. Set the environment variable VERBOSE=true
2. Run the app using yarn serve

This mode will enable the following:

• The app will log in verbose mode
• The app will use Chromium instead of a headless browser
• The app will execute the workflow whenever changes are made to the codebase rather than using cron

Author

Dhyego Calota dhyegofernando@gmail.com

License

MIT