Product overview

What Passage does, and the six things it works with.

Passage is a usage-based billing API for SaaS companies. You send us usage events; we meter them, price them against your plans, and produce invoices and exports your finance team can close the month on.

Concepts

• Event: one usage record, such as an API call, a GB stored, or an active user. Sent with POST /v1/events. See Events.
• Meter: what to count from your events: count, sum, max, or unique over a field. See Meters.
• Plan: tiered, volume, or package prices per meter, in one currency.
• Invoice: a customer’s charges for a month. Preview it any time with GET /v1/invoices/preview. See Usage and invoices.
• Export: a CSV of raw events for a date range. See CSV exports.
• Usage alert (beta; GA 2026-12-01): a threshold on a meter that fires a webhook when a customer crosses it.

Plans

Starter is free up to 1M events a month; Growth, Scale and Enterprise add meters, exports, support and SSO. See Pricing.

Currencies follow ISO 4217 codes. Timestamps are RFC 3339.

Links on this page

• https://passage.ink/docs/events
• https://passage.ink/docs/meters
• https://passage.ink/docs/usage-and-invoices
• https://passage.ink/docs/exports
• https://passage.ink/pricing
• https://en.wikipedia.org/wiki/ISO_4217
• https://www.rfc-editor.org/rfc/rfc3339