Connect an agent with a few lines of code.
One API to create agents, issue cards, set rules and take payments. Your agent calls it like any other tool.
Quickstart
From zero to first payment
The API is in early access. These examples show how it works.
API at a glance
The main endpoints
MethodEndpointWhat it does
POST
/v1/agentsRegister an agent under your companyPOST
/v1/cardsIssue a virtual card with its rulesPATCH
/v1/cards/:idChange limits, freeze or unfreezePOST
/v1/paymentsPay a merchant; rules are checked firstPOST
/v1/approvals/:idApprove or decline a waiting paymentGET
/v1/transactionsList transactions by agent, card or dateGET
/v1/credit/:agentCredit limit and the reasons behind it
Agent tools
Give your agent Steadfield as a tool
Steadfield can be added to an agent as a set of tools (for example through the Model Context Protocol), so the agent can check its balance and pay by itself.
get_balanceWhat the agent can still spendget_rulesIts limits and allowed categoriespay_merchantMake a paymentget_transactionCheck a payment’s status
Webhooks
Know the moment something happens
Signed webhooks tell your systems about every important event, so you can notify people or update your own records.
payment.approvedpayment.declinedapproval.requestedapproval.expiredcard.frozenlimit.changedrepayment.collectedEvery decline includes a machine-readable reason, like category_not_allowed, so your agent can explain it or try another way.