API reference

Simple payments API

Base URL https://api.chainsplit.io. No version prefix. No API key for the payment flow. HTTPS only.

Identity

Callback URL uniquely identifies a payment address. Identical callbacks return the same address_in.
callback_id is your order reference. Echoed on every webhook.
address plus chain is the volume key for 30-day fee tiers. The same 0x on Ethereum and Polygon does not share volume.

Harden the callback with an unguessable nonce that you store server-side and verify on receipt.

Create payment address

GET /{ticker}/create/

Query	Required	Notes
`callback`	yes	URL-encoded HTTPS endpoint. Keep it unique.
`address`	yes	Your receiving wallet for this ticker.
`callback_id`	no	Merchant reference, echoed back.
`pending`	no	`1` to receive mempool webhooks.
`confirmations`	no	Override default confirmations.
`post`	no	`1` sends webhook as POST.
`json`	no	`1` sends JSON body (implies POST).
`convert`	no	`1` includes fiat conversions.

curl -G https://api.chainsplit.io/erc20/usdt/create/ \
  --data-urlencode "address=0xYourUsdtWallet" \
  --data-urlencode "callback=https://merchant.tld/webhook?callback_id=ord_1842&nonce=u9f3" \
  --data-urlencode "pending=1" \
  --data-urlencode "json=1"

{
  "status": "success",
  "ticker": "erc20/usdt",
  "address_in": "0xdeposit...",
  "address_out": "0xYourUsdtWallet",
  "callback_url": "https://merchant.tld/webhook?callback_id=ord_1842&nonce=u9f3",
  "minimum_transaction_coin": "10.000000",
  "fee_percent": "0.750",
  "callback_id": "ord_1842"
}

Tickers

v1 is EVM-only. Same 0x address, same nonce sweeper, different chainId and RPC. Bitcoin, Solana and Tron are not in this API yet.

Asset	Ticker	Chain ID
Ethereum	`eth`	1
USDT on Ethereum	`erc20/usdt`	1
USDC on Ethereum	`erc20/usdc`	1
BNB Smart Chain	`bsc`	56
USDT on BNB	`bep20/usdt`	56
USDC on BNB	`bep20/usdc`	56
Polygon	`polygon`	137
USDT on Polygon	`polygon/usdt`	137
USDC on Polygon	`polygon/usdc`	137

Token endpoints nest the family: /erc20/usdt/create/, /bep20/usdt/create/, /polygon/usdt/create/.

Webhooks

Acknowledge with HTTP 200 and body *ok*. Anything else is retried with exponential backoff.

Verify x-cs-signature: hex HMAC-SHA256 of the raw query string (GET) or raw body (POST), keyed with the nonce you embedded in the callback. Also reject unknown nonces.

Common fields:

Field	Meaning
`uuid`	ChainSplit payment id
`callback_id`	Your reference
`pending`	`1` mempool, `0` confirmed
`address_in` / `address_out`	Deposit / destination
`txid_in` / `txid_out`	Customer tx / sweep tx
`value_coin`	Amount received at address_in
`fee_percent`	Tier applied on this sweep
`fee_coin`	Service fee in coin
`value_forwarded_coin`	Net sent to you
`confirmations`	Observed confirmations

Other endpoints

GET /info/?prices=1 — all tickers + fee_tiers
GET /{ticker}/info/?prices=1 — minima and current fee_percent
GET /{ticker}/estimate/?addresses=1 — network fee estimate (excludes service fee)
GET /{ticker}/logs/?callback=... — webhook history for an address
GET /{ticker}/qrcode/?address=&value= — QR payload

Fee application

There is no billing dashboard. On each confirmed sweep we:

Look up 30-day confirmed USD volume for (chain, address_out).
Select the tier (see Fees).
Subtract service fee and network fee from value_coin.
Broadcast the forward tx and include the breakdown in the confirmed webhook.

If the remainder would fall below dust, the payment is not sweepable. Surface minima before checkout.