Open Source Kelviq Alternatives
A curated collection of the 2 best open source alternatives to Kelviq.
The best open source alternative to Kelviq is Lago. If that doesn't suit you, we've compiled a ranked list of other open source Kelviq alternatives to help you find a suitable replacement. Other interesting open source alternative to Kelviq is Flexprice.
Kelviq alternatives are mainly Finance & Accounting but may also be Cloud Infrastructure Management. Browse these if you want a narrower list of alternatives or looking for a specific functionality of Kelviq.
Open source billing infrastructure that meters usage events, applies pricing and credits, and issues invoices for AI and SaaS products.
Lago is the programmable system between product usage and revenue. Events arrive from the application, become billable metrics, pass through pricing and entitlements, and come out as invoices, payments, and revenue, which means pricing can change without billing being rebuilt.
The engine is headless and API-first. Applications, internal tools, and agents reach the same primitives through the REST API, SDKs, webhooks, and an MCP server, while product and finance teams use the interface when a human view is faster. Metering stays independent of payment processing, so Stripe, Adyen, or GoCardless can be connected without a provider's catalog becoming the source of truth.
Pricing can be assembled from whatever usage a product actually generates.
- Token metering: charges by model and by input, output, cache, reasoning, or tool call.
- Compute usage: GPU, CPU, storage, and other consumption billed from events.
- Prepaid credits: balances with automatic top-ups.
- Subscriptions: allowances, minimum commitments, and overages on top of recurring plans.
- Two operating models: Lago Direct bills your own customers, while Lago Embedded gives platforms metering and billing to offer to theirs.
The repository ships a maintained demo that prices three AI requests locally using Docker, curl, and jq. It seeds a disposable organization, reconciles the usage total independently, and retries one transaction to prove that usage does not increase. Nothing leaves the machine, and a cleanup flag removes the isolated Compose project and its data volume afterward.
Metering and billing infrastructure for AI and SaaS teams running usage-based, credit-based or hybrid pricing without writing it themselves.
Flexprice is monetization infrastructure for teams whose pricing does not fit a standard subscription tool. Applications, agents or workflows send usage events, and the platform takes over the metering, credit application, entitlement checks and invoicing that otherwise turns into custom billing code nobody wants to maintain.
Processing happens in real time. Events arrive from your backend through Go, Python and JavaScript SDKs, or stream in from a data warehouse or analytics pipeline. Once billing is computed the results flow outward, syncing invoices to a payment processor, customer data to a CRM and revenue figures to accounting.
The core splits into a handful of pieces you can adopt separately.
- Usage metering: define granular events such as API calls, compute time or database queries and aggregate them as they land.
- Credit grants: prepaid and promotional credits, automatic top-ups at thresholds, and expiry for what goes unused.
- Pricing plans: seat-based, pay-as-you-go, volume-tiered and hybrid models, with per-customer overrides and plan versioning.
- Feature management: toggles, metered limits and configuration values enforced per plan or per customer.
- Subscriptions and invoicing: proration, overages and credits produce invoice lines tied back to tracked usage.
Written in Go and self-hostable, Flexprice suits teams that dislike percentage-of-revenue fees or opaque billing logic and want to read the code that charges their customers. Local development runs on Docker Compose, and it can layer over an existing provider such as Stripe or Chargebee instead of replacing it.
