Integrated platform

A fully integrated suite of monetization components

We bring together everything that's required to monetize API products.

Project X powers monetization infrastructure for small, medium-sized and enterprise APIs, pay-per-use and subscription-based API products, and everything in between.

We also help API providers productize their APIs, manage API consumption, reduce friction at checkout, support both self-service and sales-led approaches.

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Global scale

The gateway to international sales

Project X is integrated with Stripe and Paddle, and you can instantly start accepting international payments.

Our integration guarantees the lowest payment processing fees for Stripe and adds the missing usage-based pricing models to Paddle.

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Maximum flexibility

Materialize your vision faster

Featuring the most flexible productization engine on the market, Project X augments your product sense and allows you to implement a huge variety of API products with several mouse clicks.

And it takes just a few minutes to set up your API product on Project X.

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Fit for startups

Try new ideas more quickly

Project X significantly reduces the time to market for your API. It allows you to quickly test and validate new ideas for API products, picking those with maximum profit.

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Minimal effort

Low & no-code

The hardest parts of API business are coming up with a profitable idea and marketing it. Project X relieves you of secondary tasks and frees up your time, so that you can dedicate yourself to the primary ones.

Forget about writing integration code. All components of Project X are already integrated in the most efficient way, and you can focus on the business.

Demo checkout

See through the eyes of your customers

Try creating a subscription to our demo API product and see Project X self-service checkout in action.

Test mode. No real payments will be made.

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  • Lite

    29 / month

  • 1 million API calls/month
  • +€12.9 each other 1M API calls
  • No transaction fees
  • API Checkout Links
  • Custom styling
  • Own domain name +€9.99
  • Full monetization suite
  • 2-week free trial
  • Professional

    299 / month

  • 50 million API calls/month
  • +€12.9 each other 1M API calls
  • No transaction fees
  • API Checkout Links
  • Custom styling
  • Own domain name
  • Full monetization suite
  • 2-week free trial
  • Custom

    ? / month

  • Custom terms to fit your needs
  • Pricing that works for you
  • As many API calls as you need
  • Dedicated cluster
  • Priority support


  • Simple

    0 / month

  • Unlimited API calls
  • 5% fee on each paid invoice
  • Free until you have paying customers
  • API Checkout Links
  • Custom styling
  • Own domain name
  • Full monetization suite

What is Project X?


Reduce the time to market from weeks to minutes by leveraging our all-in-one solution for API monetization.

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Manage consumption

Be in control of how your customers use your APIs. Apply individual terms with several clicks. Impose limits on product-relevant metrics.

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Turn your APIs into attractive API products and manage their full lifecycle. Provide access to premium features for advanced users. Sell API bundles.

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Enable subscriptions

Onboard your customers with ease with a ready-made subscription solution. Create API Checkout Links for your API products and use them anywhere.

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Bill and collect payments

Define pricing models of any complexity. Offer tiered pricing and pay-per-use to your customers. Use our billing solution and Stripe integration to issue invoices and collect payments automatically.

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Forget the integration

All of the features are available with no need to write integration code.


You define the product.
Project X puts together the necessary parts.


Single API, a bundle of APIs, or any combination of endpoints from any number of APIs — you decide what you sell.

Hard & soft quotas

Cut access after the quota limit is exceeded.

Allow paid overages to maximize revenue.

Recurring quotas

Reset the quota after a period of time.

Custom quota units

Set limits for:

  • - number of API calls
  • - uploaded bytes
  • - characters in a query
  • - sent messages
  • - anything else

Cross-API quotas

A quota can be shared by many endpoints or APIs.

Rate limits too.

Premium features

Allow access to a wider range of features for users with premium subscription.

Custom products

Negotiate individual terms with the customer and implement them easily.

Zero integration

All that is possible without writing any code.


In simple words, you only need to develop an API.
Then you use Project X for the rest: add the API on Project X, create a new product and choose the endpoints to be included, set up quotas and other limitations, define the pricing model and get a self-service checkout link for your customers.
If you plan to take money for your services, you also need a Stripe account. That's it.

General-purpose billing solutions focus on the process of issuing a bill.

They allow to define pricing models and issue invoices. Stripe and ChargeBee also perform payment processing.

Project X, on the other hand, aims to be a turnkey solution covering all aspects of selling API-based products, so that the only thing an API providers needs to do is to develop an API. Billing is one of these aspects.

A high-performance cloud API gateway is one of the components of Project X, enabling high levels of automation.

Thanks to it, Project X can automatically authenticate customers, grant access when a subscription is activated, cut access when a hard quota limit is exceeded, impose rate limits, implement premium features, track per-customer usage and turn that data into invoices.

Project X API gateway also serves as a TLS termination proxy for the APIs. It uses SSL certificates from a trusted vendor, so your customers have a secure connection to your API, and allows using self-signed certificates on the API side, so you don't have to buy SSL certificates yourself.

Very performant. Internal engine-added latency lies in the millisecond range. Project X also uses some optimizations in order to minimize the network latency.

Project X is a cloud-based solution. Currently, there is no on-premise version available. However, Project X team can set up a managed dedicated cluster for you, which will be completely separated from the public infrastructure.

Yes, that is possible. Project X Products are extremely flexible: your customers can subscribe to one API, several APIs or any combination of endpoints from any number of APIs.

If there are some endpoints which you'd like to be accessible by users with premium subscription, you could, for instance, create two products, e.g. "Basic" and "Premium". The "Basic" product would exclude the premium endpoints, which will only be accessible in "Premium" product.

Project X has its own billing engine.
You need to define a pricing model for each product and, after a customer subscribes to your product, Project X tracks per-customer usage, calculates amounts due and issues invoices to be paid by the customer.
If an invoice is not paid after the payment due date, the subscription is paused until invoices are settled.

Project X uses Stripe for payment processing.
Payments initiated by Project X are made directly to your Stripe account so you're always in control of your funds.

Each transaction processed with Stripe is subject to several fees.
The first one is the fee for processing the payment. It varies based on the payment method/country/etc.
If additional services are used (invoicing, recurring payments, solution for marketplaces), each of them adds its own fee on the transaction. The more products you use, the bigger the fee.

Payments initiated by Project X use the most basic functionality of Stripe: processing payments. This ensures the minimum possible fee.

Latest News

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Big August Release

Automated payment collection, docs and ToS links, customer dashboards.

API Checkout Links: instant checkout pages for your API

API Checkout Links — a unique product offered by Project X allowing you to instantly set up a checkout page for your API products without any coding.

How to monetize your API with Project X

If you're not a big fan of writing boilerplate code, you might find interesting the approach we've taken at Project X to help API providers monetize their APIs.

API monetization challenges: charge once

In most cases, API pricing models imply that each call to a paid endpoint is billed. However, there are scenarios when you'd like to charge your API consumer only for the first call.

The Fastest Time To Market For Your API

Bringing a new API product to the market can be challenging in many ways. One of the most time-consuming tasks in this process is implementing API monetization.

API pricing: internal currency or credit-based model (coins, credits, etc.)

A credit-based pricing model, otherwise known as internal or virtual currency, is widely adopted in “Swiss Army Knife”-kind of API products that provide a rich set of APIs for many applications.

Beware the uncapped pay as you go

With plain Pay-as-you-go API subscription plan, it's easy for the customer to end up in a situation like on the following invoice...

API Monetization with Project X — Mortgage Calculator API

With Project X API Monetization you can instantly turn an API into a product, deliver it to customers and get paid.

Products, API bundles and more

Several APIs combined into one product, API bundles, cross-API quotas and rate limits — in the new release of Project X.

Editing individual subscription plans

Sometimes a customer needs to increase a limit, to enable some premium feature, etc. In other words, the customer needs a subscription plan tailored to their needs.

How does Project X go about it?

Google-like Text-to-Speech API pricing with Project X

Google's Text-to-Speech API is priced based on the number of characters sent to the API to be synthesized into audio each month.

See how it can be implemented for any API without writing code.

API billing for uploaded data volume

For APIs which imply a significant incoming traffic from customers (e.g. image processing API, file hosting API, etc.), the ability to bill customers for the amount of uploaded data is an absolute must.

Adding more visibility on API usage

With the new release, each subscription on Project X gets a dashboard showing per-quota usage for each billing period.

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