Using Payday

Environments

Two isolated services with the same API. Production settles real USDC on Monad; the sandbox settles Circle's test USDC on Monad testnet, with its own accounts, keys, and database.

	Production	Sandbox
API	`https://api.payday.sh`	`https://api.sandbox.payday.sh`
Keys	`payday_live_…`	`payday_test_…`
Chain	Monad mainnet (chain id 143)	Monad testnet (chain id 10143)
Token	Circle-issued native USDC	Circle test USDC
Funds	Real	Test tokens from a faucet
Indexing and finality	Real	Real: the same indexer, the same finality gate
OpenAPI	`/openapi.json`	`/openapi.json`

Every deposit request reports the chain and token it accepts. Read them from the response rather than hard-coding them, and show them to the payer: a matching symbol is not enough, and USDC on another network, bridged USDC, and look-alike tokens do not count.

Using the sandbox#

Point the client at the sandbox origin with a test key. Everything else is the same: the routes, the fields, the statuses, the webhooks, the proof.

TypeScript

const payday = new PaydayClient({
  apiKey: process.env.PAYDAY_TEST_API_KEY!,
  baseUrl: "https://api.sandbox.payday.sh",
});

Shell

curl -fsS "https://api.sandbox.payday.sh/v1/deposit-requests/dr_…" \
  -H "Authorization: Bearer payday_test_..."

There is deliberately no "mark as paid" button. To settle a sandbox request, open its link as the payer, sign the wallet step, and send test USDC from that wallet. What you then watch is the real pipeline: finalized transfer, credit, settlement, proof.

Status and health#

GET /health is unauthenticated readiness: ok when the API can reach its database.
GET /v1/status, with a key, reports the chain's finalized position, the indexer's cursor and lag, and the settlement queue. See Account and status.
Every response carries X-Request-Id. Quote it to support.