Billing
Per-developer monthly subscription plans for Sebastion AI, and pay-as-you-go rates for the API gateway.
Sebastion AI is billed per developer, per month. Foundation Machines bills monthly with no setup fees and no annual commitments.
Subscription plans
Plans are per-developer, per-month, billed in USD.
| Plan | Price | Audit model | Best for |
|---|---|---|---|
| Free | $0 | Claude Sonnet 4.6 | Solo developers and OSS |
| Pro | $19 / dev / month | Claude Opus 4.7 | Small teams shipping production code |
| Team | $39 / dev / month | Claude Opus 4.7 (multi-model cross-check coming) | Growing engineering orgs |
| Enterprise | Custom | Best frontier model + on-prem option | Regulated and large orgs |
Each plan also includes a daily token cap and a per-minute request rate
on the gateway, see rate limits and access to a
curated set of frontier models on /v1/chat/completions, see
models.
The full feature breakdown lives on the pricing page.
How per-developer billing works
Pro and Team are billed only for developers who author pull requests in the last 30 days in repositories where Sebastion AI is installed. Inactive collaborators, reviewers, maintainers who only merge, bots or anyone who hasn't opened a PR in the trailing 30-day window, are free.
Practically:
- Install on a 50-person org but only 8 engineers ship PRs each month? You pay for 8 seats, not 50.
- A developer who opens a PR after a long break re-activates that month.
- Authorship is attributed by the GitHub account on the PR, not by commit author, so co-authored commits don't double-count.
You can see the live billable seat count in the billing portal.
API gateway pay-as-you-go
For power users calling /v1/chat/completions directly: when your daily
token cap is exhausted, requests succeed at the per-million-token rates
below. Token usage is metered at the upstream provider rate
(prompt + completion).
| Bucket | Models | Rate (USD / 1M tokens) |
|---|---|---|
| Fast | Claude Haiku 4.5, GPT-5.4 mini, Gemini 3 Flash | $0.60 |
| Balanced | Claude Sonnet 4.6, GPT-5.4 | $3.50 |
| Frontier | Claude Opus 4.7, Kimi K2.5 (on launch) | $18.00 |
Rates are inclusive of upstream provider costs and our gateway fee. We do not charge separately for context tokens.
Invoices and payment methods
Billing runs on Stripe. View invoices, change plans, update cards and download receipts in the billing portal.
Cancelling
Cancel any time from the billing portal or by emailing lewis@foundationmachines.com. Service continues to the end of the current billing period; we do not pro-rate refunds.