changelog / twins / billing

Stripe, Plaid and Notion twins

Twinbay team
Stripe, Plaid and Notion twins

You can now test agents that take payments, read bank data or write to Notion. Add the Stripe, Plaid or Notion twin to an environment and point the provider's official SDK at it.

Stripe twin

The Stripe twin covers the payments an ecommerce agent handles: customers, payment methods from Stripe's test cards, payment intents with manual or automatic capture, charges, refunds, disputes and payouts. A declined payment can succeed on retry. When you advance the environment, dispute deadlines pass and pending funds become available.

Billing and checkout work too. Your agent can create subscriptions, invoices, coupons and promotion codes, open Checkout sessions and payment links, save cards with setup intents, and manage tax rates and tax IDs. Test cards that require 3D Secure ask for authentication first, as they do on Stripe.

Stripe Tax calculations return zero tax when the account has no active registration for the address. A calculation that would collect tax returns a not-modelled response for now, as do credit notes, quotes, subscription schedules and metered prices. See the Stripe twin docs for the full list.

Plaid twin

Each Plaid environment starts with one bank login already linked at First Platypus Bank, with the same accounts and transactions you'd get in Plaid Sandbox. Your agent can go through Link, sync transactions, read balances and ACH numbers, and fix an Item after a login error.

Identity, Investments, Liabilities, Statements, Assets reports and Transfer are also available. Some events are hard to trigger in Sandbox. Here they happen when you advance the environment: a pending transaction posts, a report finishes, an Item asks the user to log in again. Each change sends a signed webhook.

Notion twin

The Notion twin uses API version 2025-09-03, where one database can hold several data sources. Your agent can query data sources with filters and sorts, create and edit pages and their properties, add blocks, comment and search. Pages that aren't shared with the integration stay hidden, and rate limits apply as they do on Notion.

The OAuth flow, file uploads, views and comment edits return a not-modelled response.

GitHub: Git and app sign-in

The GitHub twin now includes a Git server. Clone, fetch and push over HTTPS with the regular git CLI. Pushes show up in the API right away, so a pull request opened from a pushed branch points at the commit you pushed. Merges go into the repository's Git history.

The twin also gained file contents, forks, collaborators, teams, releases, milestones, reactions, sub-issues and issue types. Pull request reviews can comment on lines of the real diff. Search covers repositories, issues, commits, code and users.

Agents that sign in as an OAuth app or a GitHub App can now run against the twin. It supports the web and device flows, refresh tokens, app JWTs and installation tokens. Each token reaches only the repositories and permissions it was granted.

Billing

Billing has its own page in the console, under Settings or the user menu. It shows your plan, remaining credits, the amount due this period, your payment method and past invoices. The usage table lists each unit price and the credits applied.

Plan limits are now in effect. On Free, you can run up to five twins at once and each environment runs for one hour. Pay-As-You-Go adds charges for seed and test builds. The pricing page lists the current rates.

Improvements

  • Team: Admins can invite people and rename the organization from Settings › Team.
  • Environments: The twin picker lists twins alphabetically.
  • MCP: Each tool now says whether it reads, changes or deletes data. MCP clients can use that to decide when to ask before running a tool.

Fixes

  • Fixed the API keys page failing to load.
  • Twins start and stop more reliably.

API

  • The tests API has simpler routes. POST /tests/{id} adds a test version, replacing POST /tests/{id}/versions. POST /evaluators builds an evaluator, replacing POST /test-versions/{id}/compile. POST /evaluations records a checkpoint or final evaluation, replacing POST /test-runs/{id}/evaluations.
  • To regrade a run, call POST /evaluations with another evaluator for the same run. This replaces POST /evaluations/{id}/regrade.

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