Brex

Seven of Brex’s APIs: Team, Transactions, Payments, Expenses, Budgets, Fields and Accounting. An agent pointed at Brex writes to it — issuing and locking cards, setting spend limits, paying vendors, attaching receipts and coding expenses — and three things are easy to get wrong: card creation, transfers and every budget write require an Idempotency-Key; every operation needs its own scope, and cards does not grant cards.pan; and the Accounting API refuses in an envelope of its own. Brex publishes no client library, so the conformance suite pins the seven OpenAPI documents Brex serves and validates every response the twin gives against them. Slug: brex

What it models

Area	Modelled
Starting account	One company with its account admin, its root budget, its card account and a primary Brex Cash account
Authentication	A `bxt_…` user token in `Authorization: Bearer`, carrying scopes; every operation’s scope enforced; invalid, revoked, expired and orphaned tokens; 1,000 requests a minute and 5,000 cards a day
Company and team	The company, the current user, users invited or loaded, departments and locations
Cards	Virtual and physical cards with spend controls, locked, unlocked and terminated; test-range card numbers through `/pan`
Budgets and spend limits	The budget hierarchy, spend limits with `HARD` and `SOFT` authorization and balances projected from card spend, period rollover, read-only budget programs, and the legacy `/v1/budgets`
Accounts and transactions	Card and cash accounts with balances projected from their transactions, card and cash transactions, statements
Payments	Vendors and their payment accounts, transfers through approval, scheduling and processing, failures restoring the balance
Expenses and receipts	Card expenses with filters and expansions, memos, receipts uploaded to pre-signed URIs the container serves and read back through download URIs
Custom fields	Fields and their values, addressed by `brex_id`, `remote_id` or `value_id`, in bulk
Accounting	One active integration, accounting records and their export results, in the Accounting API’s own error envelope
Errors and paging	Brex’s `{"type", "message", "code"}` envelope, cursor pagination with `limit` up to 1000, `Money` in integer minor units

Advancing moves transfers towards PROCESSED, activates shipped cards and locks cards past their lock date, rolls budgets and spend limits into their next period, expires receipt URIs and resolves receipt matches.

Not modelled

Titles, cost centers and legal entities, incoming transfers and linked accounts, partner OAuth, and the whole of the Onboarding, Travel and Webhooks APIs. An endpoint Brex has and the twin has not built answers an explicit 501 NOT_MODELED in Brex’s envelope; a path Brex does not have is a 404.

Getting Started

Concepts

Interfaces

Request a twin

What it models

Not modelled

​What it models

​Not modelled

What it models

Not modelled