Flexprice is a free, open source cloud infrastructure management project written in Go and released under AGPL-3.0. It has 5,510 GitHub stars, 494 forks and 227 open issues, and was last pushed 9 hours ago. On this registry it ranks #26 of 43 tracked projects in Cloud Infrastructure Management, with 5 head-to-head comparisons available. It gained 48 stars over the last 6 tracked days.

What is Flexprice?

Flexprice is an open-source metering and billing platform that lets AI-native and SaaS teams run usage-based, credit-based, and hybrid pricing with real-time metering and reporting, and it is built for developers who would otherwise have to write billing infrastructure from scratch.

What it is

Flexprice is an open-source project, written in Go and licensed under AGPL-3.0, that provides metering, credits, pricing, and billing as one composable core that can run in the cloud or self-hosted. Its architecture is explicitly open: an application, whether it exposes backend APIs, runs AI agents, or drives custom workflows, sends usage data to Flexprice, and data can also be streamed in from data warehouses or analytics pipelines. Flexprice processes that data in real time, calculates pricing based on the customer's plan, applies prepaid or promotional credits, enforces feature limits, and generates invoices automatically. A no-code UI sits alongside the API and the language SDKs.

The concrete problem it solves is that billing work repeatedly becomes a developer problem. Traditional billing services handle simple subscriptions or payments, but usage metering, credit systems, feature gating, and custom invoice logic usually fall outside what they support out of the box, so developers write workarounds or custom logic and then maintain it. Accurate usage tracking is difficult on its own, because it means capturing high-volume events, aggregating them in real time, and handling edge cases such as prorations and time zones. Flexprice replaces that hand-built layer with a dedicated service, and it also stands in for closed third-party billing platforms that charge a percentage fee on revenue and leave teams locked in with limited control over pricing logic and their own data.

Key capabilities

  • Real-time usage metering fed by application events, AI agents, custom workflows, or streams from data warehouses and analytics pipelines.
  • Pricing model support spanning seat-based subscriptions, usage-based pricing, prepaid credit bundles, and hybrid combinations, iterated on without rebuilding billing infrastructure.
  • Credits and top-ups, including automatic application of prepaid and promotional credits before an invoice is generated.
  • Feature gating and feature limit enforcement, so plan entitlements are checked as part of billing rather than in separate custom code.
  • Automatic invoice generation with downstream sync to payment processors, CRM, CPQ, and accounting tools, including pushing revenue numbers to accounting systems.
  • Client SDKs published as github.com/flexprice/go-sdk for Go, flexprice on PyPI for Python, and @flexprice/sdk on npm for JavaScript.
  • Infrastructure footprint indicated by its topic set: PostgreSQL, Kafka, ClickHouse, and Temporal, alongside Stripe and Stripe subscriptions integrations.

Who uses it and how

  • AI-native and SaaS teams that operate usage-based, credit-based, or hybrid pricing and need metering and reporting that keeps up as the product evolves.
  • Backend and platform engineering teams that push usage events from application APIs, AI agents, or custom workflows into a metering service instead of maintaining their own aggregation pipeline.
  • Data and analytics teams that already hold usage data in a data warehouse or analytics pipeline and stream it into Flexprice rather than duplicating ingestion.
  • Teams migrating away from closed billing providers that take a percentage of revenue and restrict control over pricing logic, or that want invoice data flowing into existing payment, CRM, CPQ, and accounting systems.
  • Operators who prefer self-hosting over a managed service, with a cloud option and a Slack community available for either path.

Getting started

Start from the hosted platform at flexprice.io or deploy the open-source core self-hosted, then integrate using the Go, Python, or JavaScript SDKs; documentation lives at docs.flexprice.io and a walkthrough demo is linked from the README.

How it compares

Among the tools named in its facts, Stripe appears as an integration target for payments and subscriptions rather than as a direct replacement: Flexprice owns the metering, credits, pricing, and invoice computation layer and then syncs invoices outward to a payment processor. The closed SaaS billing providers described in the README are the contrast point on licence and ownership, since they are closed systems and commonly charge a percentage fee on revenue, while Flexprice is AGPL-3.0 and can be run on your own infrastructure with your data in place.

When to use it — and when not to

Choose Flexprice when you need usage metering, credits, feature gating, and invoicing under your own control, and you are prepared to operate the stack it depends on: PostgreSQL, Kafka, ClickHouse, and Temporal all appear in its topic list, so self-hosting means running and scaling those systems yourself. Do not pick it if you want a fully managed service with no infrastructure to operate, or if AGPL-3.0 copyleft obligations do not fit your distribution model. Note also that the repository carries 227 open issues, so teams should expect an actively moving project rather than a settled one.

project readme (upstream, from github) — read inline

Monetization Infrastructure Built for AI Native Companies

Flexprice lets AI-native and SaaS teams operate usage-based, credit-based, and hybrid pricing with real-time metering and reporting that scales as your product evolves.

DocsDemoWebsiteLinkedInXSlack Community

Go Python JavaScript

flexprice%2Fflexprice | Trendshift

Flexprice - Usage-based pricing and metering for developers | Product Hunt


Open architecture

The Flexprice core (metering, credits, pricing, billing) has an open and composable design.

Your application, whether it's running backend APIs, AI agents, or custom workflows, can send usage data to Flexprice. You can directly stream data from data warehouses or analytics pipelines as well.

At the core, Flexprice processes this data in real time. We handle everything that usually ends up as custom logic built by developers. Our platform calculates pricing based on the customer’s plan, applies any prepaid or promotional credits, enforces feature limits, and generates accurate invoices automatically. Whether you're using seat-based subscriptions, usage-based pricing, or prepaid credit bundles, you can set up and iterate on your pricing model without writing billing infrastructure from scratch.

After billing is computed, our platform connects to your existing tools for payments, CPQ, CRM, and accounting, ensuring billing information flows into the systems your business already uses. It can sync invoices to your payment processor, update customer data in your CRM, and push revenue numbers to your accounting tools.

With this architecture, you get full control over how billing works inside your product, while saving your team from the complexity of maintaining it all.

Why billing is a developer problem?

TL;DR

When existing billing tools don’t flex to your product’s needs, developers shoulder the burden eating up valuable development time and causing ongoing maintenance headaches.

Modern app developers often find themselves wrestling with billing systems. Here are some of the biggest pain points that turn billing into a “developer problem”:

  • Rigid billing tools (lack of flexibility): Traditional billing services handle simple subscriptions or payments, but anything beyond that – usage metering, credit systems, feature gating, custom invoice logic – usually isn’t supported out of the box. Developers end up writing countless workarounds or custom code to accommodate these needs. In other words, if your pricing model doesn’t fit the tool, you’re stuck bending your product or building logic from scratch.

  • Complex usage metering at scale: Implementing accurate usage tracking is hard. It involves capturing high-volume events, aggregating them in real time, handling edge cases (prorations, time zones, etc.), and ensuring it all works reliably at scale. Few teams anticipate how many moving parts this requires until they’re deep in the weeds of building it.

  • Vendor lock-in and black boxes: Relying on third-party billing platforms can mean surrendering flexibility. Many SaaS billing providers are closed systems or charge a percentage fee on revenue, which frustrates engineers who want full control over their pricing logic and data. Changing providers later can be a massive undertaking, so teams feel “stuck” with a less-than-ideal solution.

  • Delayed monetization & opportunity cost: Every week spent building or patching a billing system is a week not spent on core product features. If it takes months to implement a new pricing model or usage-based feature, that’s delayed revenue and lost agility for the business. What might be scoped as a “quick two-month project” can quickly spiral into a multi-year maintenance headache, tying up engineering resources and slowing time-to-market for new offerings.

How Flexprice solves this

Flexprice’s approach is to abstract away the hard parts of billing while preserving maximum flexibility and transparency for developers. It addresses the above pain points in several key ways:

  • Developer-first design: Flexprice is built API-first with easy integrations. You can instrument your app by simply sending usage events via SDKs, and Flexprice handles the aggregation, metering, and billing logic in real time. This means minimal code to write on your end and no need to reinvent metering or invoice calculations.
  • Open-source and self-hostable: Flexprice is open-source, so you can run it on your own infrastructure for full transparency and control. There’s no black-box dependency or surprise fees and you’re free from vendor lock-in. You can inspect the code, extend functionality, and trust that your billing logic is fully in your hands.
  • Composable with your stack: Rather than replacing your existing billing or payment provider, Flexprice augments it. You can build it from scratch or build on top of your existing billing providers like Stripe or Chargebee to manage usage data, pricing rules, credits, and entitlements. You can easily integrate with your existing payment gateways, CRM, CPQ, etc. This layered approach preserves your current workflows and customer touchpoints.
  • Flexible pricing models out-of-the-box: Whether you need pure usage-based billing, tiered plans, seat-based subscriptions, prepaid credits, free tiers with overage, or any hybrid model, Flexprice’s data model and rules engine can support it. Flexprice is designed to accommodate changing pricing strategies in minutues that would normally require schema updates and migration scripts.
  • Transparency and visibility: Because Flexprice meters every event and ties it to billing, you (and your customers) get clear visibility into usage and charges. It can provide real-time usage summaries and cost reports, helping both engineering and finance teams ensure everything lines up correctly. Customers get detailed invoices that show exactly what they’re paying for, reducing billing disputes or confusion.

By handling the heavy lifting from real-time usage tracking to invoice generation, Flexprice lets your team focus on building your actual product, not the billing system around it

Features

Flexprice provides a rich set of features to power usage-based and hybrid billing models. Key features include:

  • Usage Metering: Define custom usage events (API calls, compute time, database queries, etc.) at a granular level and track them in real time. Flexprice’s metering system can handle millions of events and aggregates usage data reliably, even at peak load. This ensures your billing is always up-to-date with actual customer usage.
  • Credit Grants (Prepaid & Promotional Credits): Support credit-based workflows with full control. You can grant prepaid credits or promotional credits to customers, set up automatic top-ups at thresholds, and expire unused credits as needed. Flexprice’s credit system is built-in, so you don’t need extra custom logic to handle one-time credits or wallets.
  • Pricing Plans: Design and iterate on pricing models with total flexibili

readme truncated — read the full docs on github

Frequently asked questions

Is Flexprice free to use?

Flexprice is open source under the AGPL-3.0 licence. There is no licence fee and no seat count — you can self-host it or, where the project offers one, pay a vendor for a managed version instead.

What does Flexprice do?

Open source metering and billing infrastructure for any pricing model

What is Flexprice written in?

Flexprice is primarily written in Go. Its source is publicly available at https://github.com/flexprice/flexprice, and it has 5,510 GitHub stars.