Lago Has a Free API: The Open-Source Billing Platform for Usage-Based Pricing Without Stripe Billing Complexity

#lago #api #billing #saas

Usage-based pricing is the future of SaaS. But implementing it means tracking events, calculating invoices, handling proration, and managing subscriptions. Lago does all of this — open source, self-hostable, and with a clean API.

What Is Lago?

Lago is an open-source metering and billing platform. It tracks usage events, applies pricing models, generates invoices, and integrates with payment providers. Think Stripe Billing, but open source and designed specifically for usage-based pricing.

The Free Platform

Lago is completely free and open source:

Usage metering: Track billable events in real-time
Flexible pricing: Pay-as-you-go, tiered, volume, package pricing
Subscriptions: Recurring billing with add-ons
Invoicing: Automatic invoice generation
Coupons and credits: Promotional pricing tools
Webhooks: Real-time billing event notifications
Payment integration: Stripe, GoCardless, Adyen
REST API: Full programmatic control

Quick Start

Self-host with Docker:

git clone https://github.com/getlago/lago.git
cd lago
docker compose up -d

Or use Lago Cloud (free tier available).

Track usage events:

import { Client } from 'lago-javascript-client';

const lago = Client('your-api-key');

// Send usage events
await lago.events.createEvent({
  event: {
    transaction_id: 'txn_123',
    external_customer_id: 'cust_456',
    code: 'api_calls',
    timestamp: Math.floor(Date.now() / 1000),
    properties: {
      tokens: 1500,
    },
  },
});

Define pricing:

# Create a billable metric
curl -X POST https://api.getlago.com/api/v1/billable_metrics \
  -H 'Authorization: Bearer YOUR_KEY' \
  -d '{
    "billable_metric": {
      "name": "API Calls",
      "code": "api_calls",
      "aggregation_type": "sum_agg",
      "field_name": "tokens"
    }
  }'

# Create a plan with usage-based pricing
curl -X POST https://api.getlago.com/api/v1/plans \
  -H 'Authorization: Bearer YOUR_KEY' \
  -d '{
    "plan": {
      "name": "Pro Plan",
      "code": "pro",
      "interval": "monthly",
      "amount_cents": 2900,
      "charges": [{
        "billable_metric_code": "api_calls",
        "charge_model": "graduated",
        "properties": {
          "graduated_ranges": [
            {"from_value": 0, "to_value": 10000, "per_unit_amount": "0", "flat_amount": "0"},
            {"from_value": 10001, "to_value": null, "per_unit_amount": "0.001", "flat_amount": "0"}
          ]
        }
      }]
    }
  }'

Why Teams Choose Lago

An AI startup needed usage-based billing for API calls. Stripe Billing could not handle their pricing model (graduated tiers based on token count). Building custom billing took 2 months and was full of edge cases. After switching to Lago, they had accurate metering, automatic invoicing, and graduated pricing working in a day.

Who Is This For?

SaaS companies with usage-based or consumption pricing
AI/API companies billing per request, token, or compute unit
Infrastructure companies with metered services
Teams outgrowing Stripe Billing for complex pricing models

Start Billing

Lago handles the complexity of usage-based billing. Track events, apply pricing, generate invoices — all open source.

Need help with billing infrastructure? I build custom SaaS solutions — reach out to discuss your project.

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