Turnkey API Monetization

Project X offers an integrated solution providing subscriptions, access and consumption control, billing, invoicing, payment collection and many other features — everything you need to start monetizing your APIs.

Our self-service checkout with one-click login ensures smooth user onboarding, resulting in increased revenue for you.

All features of Project X API Consumption Management included.

Monetize Now Product deck

Market it your way

With Project X, you're free to market your offering in the way you like.

For each API product you can create a Checkout Link that brings customers directly to the checkout page. This link can be used in your marketing campaigns as a URL for call-to-action buttons.

Just create a beautiful langing page with your unique design and use that URL for the big red blinking “Subscribe” button.

User experience prior to checkout is under your full control.
The rest is done by Project X.

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Validate API ideas

"Quickly validate an idea and move on if it doesn't work" — this well-known advice is applicable to API products as well.

Project X helps reduce the time to market for your APIs from weeks to minutes by eliminating the hassle of implementing secondary features.

With monetization solution from Project X it becomes extremely cheap to validate your API ideas.

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With a big variety of pricing models supported, Project X is able to implement your pricing regardless of its complexity.

Pay as you go, freemium, tiered pricing, volume discounts, flat fees and many more.

Full control over payment process: payments go directly into your Stripe account.

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Read next: API Consumption Management


  • 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

Live demos


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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