> ## Documentation Index > Fetch the complete documentation index at: https://agents.laso.finance/llms.txt > Use this file to discover all available pages before exploring further. # Exchange an API key for a session > Exchanges a durable `lasoak_` API key for a short-lived `id_token` (one hour) plus a `refresh_token`, and returns an `auth_url` to hand your human so they can watch what you do. This is the first call an agent makes. The reply's `id_token` authenticates every other endpoint here. If you have no key, your human creates one at https://laso.finance/agent/dashboard — there is no other way to obtain one. Served from the Cloud Function URL (`https://us-central1-kyc-ts.cloudfunctions.net/agentAuth`), not the `https://laso.finance` base URL used by the paywalled routes. Send the `id_token` from `/auth` as a Bearer token, with a plain JSON body (no `data` wrapper). Free. ## OpenAPI ````yaml /api-reference/openapi.json post /agentAuth openapi: 3.1.0 info: title: Laso Finance x402 API version: 1.0.0 x-docs-revision: 106571cd77c5 x-docs-manifest: https://laso.finance/.well-known/docs-version.json contact: email: agents+support@laso.finance x-guidance: >- Laso Finance is a payment-gated (x402) API that lets an AI agent spend USDC on real-world financial products: prepaid cards (U.S. and international), gift cards, push-to-card transfers to USD/EUR/GBP debit cards, and Venmo/PayPal payouts. Payment: every paid route is an x402 v2 endpoint. Call it with no payment header to receive a 402 challenge listing the accepted networks, then replay with a signed USDC payment. Both Base (eip155:8453) and Solana (solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp) are accepted on every paid route; the caller picks either chain. Identity: `GET /auth` is free and identity-only. Prove wallet ownership with a `SIGN-IN-WITH-X` (CAIP-122) header to receive a Firebase id_token, then send that token as a Bearer credential to the authenticated read routes (`get-card-data`, `get-account-balance`, `get-kyc-status`, etc.). Paid routes also return fresh auth credentials in their response, so a payment is never required just to obtain a token. Recommended flow: (1) `GET /auth` to establish identity, (2) call a paid route (e.g. `GET /get-card`) to purchase a product, paying USDC on Base or Solana, (3) poll the authenticated read routes with the returned Bearer token to fetch the resulting card/transfer details. Full machine-readable instructions live at https://laso.finance/SKILL.md. description: >- Payment-gated API for Laso Finance. All paywalled routes use the x402 protocol — the caller includes a USDC payment header on Base (eip155:8453) or Solana (solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp) and the server verifies payment before processing. Free routes require no payment header. ## Getting started To set up a wallet for making x402 payments, choose a provider: - **Locus** (default): https://paywithlocus.com/SKILL.md - **Sponge**: https://wallet.paysponge.com/skill.md — automatic x402 service discovery - **Ampersend**: https://www.ampersend.ai/getting-started.md — self-custody on Base or Solana with dual-approval spending limits. Laso Finance is a default skill, so no manual endpoint registration is needed. ## How x402 works 1. Call a paywalled endpoint without a payment header → receive a `402 Payment Required` response containing payment details (price, recipient address, network). 2. Construct an x402 payment header using the details from the 402 response. 3. Replay the request with the payment header → the server verifies payment and processes the request. ## Authentication flow `GET /auth` is free: callers prove wallet ownership by sending a `SIGN-IN-WITH-X` header (CAIP-122 wallet signature). Paywalled routes (`/get-card`, `/order-gift-card`, `/get-push-to-card`, `/order-intl-card`) also return fresh auth credentials in their responses, so a payment is never required just to obtain a token. Most routes return auth credentials (`id_token`, `refresh_token`, `expires_in`). Use the `id_token` as a Bearer token to call authenticated Laso Finance endpoints like `/get-card-data`. When the `id_token` expires, use `POST /auth` with `grant_type: refresh_token` to get a new one. ## Important notes The `/get-card` USA prepaid card endpoint is U.S. only — issued in USD, usable at U.S.-based merchants only, and physical goods must ship to a U.S. address. For non-U.S. merchants or non-USD currencies, use `GET /order-intl-card` instead (international prepaid card, admin-fulfilled within 24 hours). All cards are intended for the caller's own use. For step-by-step instructions, read https://laso.finance/SKILL.md servers: - url: https://laso.finance description: Production security: [] paths: /agentAuth: post: tags: - Agent Wallet summary: Exchange an API key for a session description: >- Exchanges a durable `lasoak_` API key for a short-lived `id_token` (one hour) plus a `refresh_token`, and returns an `auth_url` to hand your human so they can watch what you do. This is the first call an agent makes. The reply's `id_token` authenticates every other endpoint here. If you have no key, your human creates one at https://laso.finance/agent/dashboard — there is no other way to obtain one. Served from the Cloud Function URL (`https://us-central1-kyc-ts.cloudfunctions.net/agentAuth`), not the `https://laso.finance` base URL used by the paywalled routes. Send the `id_token` from `/auth` as a Bearer token, with a plain JSON body (no `data` wrapper). Free. operationId: agentAuth requestBody: required: true content: application/json: schema: type: object required: - api_key properties: api_key: type: string description: Your `lasoak_` API key. example: lasoak_... responses: '200': description: An id_token, a refresh_token, and an auth_url for your human. content: application/json: schema: type: object '400': description: A required field is missing or invalid. servers: - url: https://us-central1-kyc-ts.cloudfunctions.net ````