Our newest endpoint for transacting. Must be used to make use of our new ACHNow product, or use instant rails.

This request triggers the issuance or remittance of funds with various options to customize how the payment is sent. With this endpoint, you can send payments either as regular ACH transactions, or via ACHNow. Other custom options include if the payment should be sent via the fastest or cheapest route, and if ACH payments should be sent via Instant Settlement or Same Day.



Only accessible through HTTP requests.

We are not updating SDKs to support this endpoint.

Your app must be enabled by Sila to use RTP or ACHNow.


To Use ACHNow

You must use this endpoint to use ACHNow. /issue_sila and /redeem_sila will not use this feature.

For now, this endpoint can be used to move funds between Sila Wallets, Virtual Accounts, and linked bank accounts, but will be opened up to accepting many different payment instrument options as the source or the destination.

Sending an ACH transaction via Instant Settlement

When an ACH payment is sent via Instant Settlement, the Sila-side location is credited or debited immediately. Because we are not yet able to control the routes themselves, the transaction may not land in the outside account until later.

If you would like the payment to land as soon as possible to the outside account, we recommend making use of the Same Day ACH method.



  • Source of funds and destination for those funds are both required for transacting.
  • Either the source or the destination must be a Sila-associated or Sila-linked account or wallet.
  • Use route_selection for non-ACHNow transactions (options for standard and sameday ACH, instant settlement, card, and RTP).
    • Your app must be enabled for instant settlement, the Checkout integration, or RTP to make use of those features.
    • NOTE: Because the default behavior is fastest, it is STRONGLY recommended that if you wish to use Standard ACH that you specify this in the route_selection field.
  • Use route_selection_behavior for ACHNow transactions (fastest or cheapest).
  • If neither a route_selection or route_selection_behavior are provided, the request will default to route_selection_behavior = fastest. Please see How Payment Route is Determined chart below for more.


Transaction Amount in Decimal Units

Please be aware that the amount value for this endpoint is in decimal units, just like /issue and /redeem.


Transaction for $10 USD

/transact amount value = 1000


ACHNow Amount in Sandbox

If testing ACHNow in Sandbox, the amount MUST be $10.00 or less, or you will receive a 400 error.

Authorization / Authentication

Apps using Access Token Authorization

Use a valid access token in an Authorization: Bearer request header.

See Authenticating with an Access Token for more details.

Apps using ECDSA Authentication

Both authsignature and usersignature headers are required for this request. The usersignature header should be generated with a keypair registered to the user (either registered from the /register endpoint or the /register_wallet endpoint).

See the section on ECDSA Authentication for more detail about ECDSA signature generation.

Note - We recently renamed the field auth_handle to app_handle. For backward compatibility, auth_handle is still valid but has been removed from our documentation.

POST /0.2/transact HTTP/1.1
Content-Type: application/json
// if using OAuth2
Authorization: Bearer [GENERATED JWT TOKEN HERE]
// if using ECDSA

  "header": {
    "created": 1234567890, //required
    "app_handle": "handle.silamoney.eth", //required
    "user_handle":"user.silamoney.eth", //required
    "version": "0.2", 
    "crypto": "ETH", 
    "reference": "<your unique id>"
  "sardine_session_key": "<session key provided to Sardine>", //optional for Stearns
  "amount": 1000, //required
  "source": "<ID to uniquely identify where funds are originating from>", //required
  "destination": "<ID to uniquely identify the destination of funds>", //required
  "route_selection": "<how you want payment sent>", //optional for non-ACHNow
  "route_selection_behavior": "fastest or cheapest", //optional, ACHNow only
  "description": "transaction descriptor", //optional
  "transaction_idempotency_id": "<UUID to uniquely identify a transaction for idempotency>", //optional
  "customer_reference": "customer chosen reference string", //optional
  "ach_attributes": { //optional for ach transactions
  	"ach_descriptor": "ach descriptor in the NACHA file", //optional
    "sec_code": "3-character SEC code" //optional


HTTP/1.1 200 OK

  "reference": "<your unique id>",
  "message": "Transaction submitted to the processing queue.",
  "success": true,
  "status": "SUCCESS",
  "response_time_ms": "171", 
  "transaction_id": "UUID of the submitted transaction",
  "route_selected": "payement method used to move funds",
  "description": "optional description for the transaction"

Request Attributes


Amount, in decimal units (ie, $10.00 in USD is 1000).

Amount must be $10 USD or below for test transactions in Sandbox environment.

Payment instrument id where the funds are originate from.

Payment instrument id where the funds are sent to.
route_selectionstringOptional, but strongly recommended, for non-ACHNow transactions. DO NOT USE WITH ACHNOW.

What route you want the payment sent by. Valid options:

ach (standard ACH)
card (for CKO integration)
internal (for wallet > wallet transfers)

If not supplied, default will be route_selection_behavior = fastest.


fastest or cheapest

If not supplied, will default to fastest.

UUID to uniquely identify the transaction to make it idempotent. If transaction is submitted multiple times with the same transaction_idempotency_id, it will only be processed once.

Unique ID, used to group a series of transactions together under one ID

ACH-Specific Attributes


Max 10 characters. Description for receiver, will be passed along in the NACHA file

3 character limit. Specify the SEC code you wish to use.


Status CodeSuccess AttributeDescriptionerror_code
403falseThe fields provided would result in a transaction that cannot be processed. For example, a standard ACH transaction that would arrive on the same day.TX_NOT_POSSIBLE
400falseThe fields provided are invalid.
400falseThe mock error header provided does not apply to the transaction being submitted

How is the Payment Route Determined?

Below is a table that can be used to help determine which payment route will be used in which case.

The "->" represents a fall back, if the method to the left of the arrow is not configured then the method to the right of the arrow will be used.

Source TypeDestination TypeRoute Selection BehaviorRoute SelectionResulting Transaction Itinerary
Sila WalletSila Walletfastestledger to leger
Sila WalletSila Walletcheapestledger to ledger
Sila WalletSila Walletinternalledger to ledger
Bank AccountSila Walletfastestinstant_settlement → rtp → sameday ach → standard ach
Bank AccountSila Walletcheapeststandard ach
Bank AccountSila Walletinstant_settlementinstant_settlement
Bank AccountSila Walletrtprtp
Bank AccountSila Walletsame_day_achsameday ach
Bank AccountSila Walletachstandard ach
Sila WalletBank Accountfastestrtp → sameday ach → standard ach
Sila WalletBank Accountcheapeststandard ach
Sila WalletBank Accountrtprtp
Sila WalletBank Accountsame_day_achsameday ach
Sila WalletBank Accountachstandard ach

Payment routes in order of speed (fastest to slowest):

  1. Instant Settlement (instant)
  2. RTP (instant)
  3. Sameday ACH (1 day)
  4. Standard ACH (approx. 3 days)

Payment routes in order of cost (cheapest to most expensive):

  1. Standard ACH
  2. Sameday ACH
  3. RTP
  4. Instant Settlement

Please note that Instant Settlement is only valid for transactions from a bank account to a Sila Wallet.

Mocking Errors

You can set the Sila-Mock-Error header in a request in order to mock an error in Sandbox. The error mocked will be based on the value of the header. Please see the table below for the which values mock which errors:

Sila-Mock-Error valueDescription
aws-sqs-timeoutMocks an AWS timeout, as if AWS sqs was not functioning correctly.
ach-return-r<return code digits>Mocks a standard ach return with the specified return code. Example: ach_return_r05 mocks an R05 return
ach-late-return-r<return code digits>Mocks a late dated ach return with the specified return code. Example: ach_late_return_r16 mocks an R16 return
insufficent-fundsMocks a insufficient funds error.
delay-<time amt><time units>Mocks a delay in processing the transaction due to a service outage. Exmaple: delay-10mmocks a 10 minute processing delay. delay-10d mocks a 10 day delay
rtp-failureMocks a failure during an RTP transaction
rtp-bank-not-supportedMocks the associated bank being unable to perform RTP transactions
reserve-wallet-warningCauses the response to return the reserve wallet low warning response
reserve-wallet-nsfMocks the reserve wallet not having enough funds for the transaction
limit-exceededMocks the fund limit for the endpoint being exceeded
rtp-bank-debit-unsupportedMocks the associated bank being unable to accept RTP debits (RTP RfPs / RTP Pulls)
rtp-bank-credit-unsupportedMocks the associated bank being unable to accept RTP credits (RTP pushes)

Note that if the header does not apply to the transaction information provided, a 400 error will be returned.