Frequently Asked Questions

Most popular questions and answers about data sources, accuracy, API features, billing and account management.


  • What is userstack?

    userstack is a simple but powerful REST API built to accurately detect the device, browser and operating system website visitors are using by parsing and interpreting User-Agent strings. The API is used by more than 10,000 companies around the world, including Zendesk, Intuit and Apple. To learn more, you can get a free API access key, take a look at the API Documentation and make your first API request today.

  • Who runs the API?

    userstack is a product built and maintained by apilayer, a software company based in London, United Kingdom and Vienna, Austria. apilayer is the company behind some of the most popular API and SaaS products worldwide, including currencylayer, invoicely and eversign.

IP Data & API

  • Where is the API's data coming from?

    User-Agent detection by userstack is based on a proprietary database mapping of User-Agent strings with a complete set of devices, browsers and operating systems currently in use and on the market.

  • How often is User-Agent data refreshed?

    Our database of User-Agent strings is updated multiple times a week, ensuring accurate and up-to-date User-Agent detection even for the most recently released hardware and software.

  • How scalable is this service?

    The userstack API is powered by apilayer cloud infrastructure, a system some of the world's most popular real-time API services are running on, making it highly scalable and flexible at any step of the way.

Plans, Pricing & Payment

  • What is the difference between free and paid subscriptions?

    The userstack Free Plan is a way of getting familiar with the API, offering basic API functionality and a limitation of 1,000 monthly API lookups. As soon as you need a higher volume or advanced API features, you can choose from one of the premium subscriptions or contact us for a custom solution.

  • Which subscription plan fits my needs?

    The most decisive factor when it comes to your technical requirements is the number of monthly User-Agent strings need processing per month. Other factors include HTTPS encryption and access to the Bulk Lookups and Crawler Detection features.

    Signing up for the Free Plan is a great way of getting to know the API and implementing it without any commitments.

  • Which payment methods are supported?

    Payments can be made via credit card (Visa, MasterCard, Discover, Diner's Club, American Express). Enterprise and high-volume customers may request annual bank transfer payments to be enabled. You can change your payment method at any given time in the "Payment" section of your account dashboard.

  • Can I also pay yearly?

    Yes. If you choose annual billing, the total price of your subscription plan will be up to 20% lower than the total amount you would pay with a monthly payment frequency.

  • How can I change my payment frequency?

    In order to change your billing frequency from monthly to yearly or from yearly to monthly, you will be required to downgrade your account back to the Free Plan.

    Step 1: Navigate to the Subscription page, click "Downgrade" in the Free Plan section and confirm your downgrade. Downgrades are not effective immediately, your premium subscription will remain active until the end of the current billing period.

    Step 2: Once your billing period ends and your account downgrade has become effective, navigate back to the Subscription page and click "Upgrade" in your preferred subscription plan's section. You will now be aked to choose a new billing frequency.

    If you need any assistance changing your billing frequency, please do not hesitate to contact us.

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