How to add a charge to one subscription without affecting other customers

Last updated: July 8, 2026

Add the charge to the base plan at a price of $0, then override the price for that one customer's subscription. Lago requires every subscription-level charge override to reference an existing charge on the base plan, so there is no way to add a net-new charge directly to a single subscription without first adding it to the plan.

How it works

Lago plan overrides enforce a 1:1 structure between the base plan and the subscription-level override: each overridden charge must reference a parent_id from a charge that already exists on the base plan. Attempting to add a charge that does not exist on the base plan via PUT /api/v1/subscriptions/:external_id fails. A charge added to the base plan at $0 does not appear on any customer's invoice while it stays at $0, which is what makes this approach work. You can override the price to a non-zero amount for one customer without changing what anyone else sees.

What to do

  1. Add the new charge to the base plan with a price of $0.

  2. Edit the specific customer's subscription, either through the UI (Subscription → Edit) or via PUT /api/v1/subscriptions/:external_id with plan_overrides.charges set to the charge and its actual price.

  3. Other customers on the base plan continue to see no charge, since it remains $0 for them.

If you expect to need this kind of per-customer customization often, design plans with placeholder $0 charges from the start for any feature that might need individual pricing later.

This article reflects guidance drawn from customer case resolutions. It is not officially supported documentation and may not apply to all situations.