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Invoke

Call contract functions with typed inputs, the full ScType entry reference, read vs signed writes, and how to read results.

Invoke calls a function on a deployed contract. WebSoroban reads the contract's spec and renders a typed form: one field per argument, each validated for its Soroban type. You enter plain values, 123, true, a G… address, and WebSoroban encodes them to ScVal for you.

Open the Invoke panel (the contract console) on a deployed contract, pick a function, fill the fields, and run. Invoke is network-aware: read calls simulate free on either network; a mainnet write shows its fee, asks you to confirm, and is signed by your connected wallet in the browser (or the custodial opt-in). See Networks.

Read vs write#

Every call is simulated first. What happens next depends on whether the function changes state.

• read-only A function that only reads storage is a read. Click Run (simulate). Nothing is signed or submitted; the return value comes back immediately and costs nothing.
• signed A function that writes storage or requires authorization is a write. WebSoroban shows the simulated result first, then you click Invoke & sign to sign with your wallet and submit the transaction.

WebSoroban decides read vs write from the simulation's footprint and auth, you don't mark a function as one or the other.

Entering each Soroban type#

The form picks an input control from the argument's ScType. Enter values exactly as below, WebSoroban converts the string you type into the right ScVal.

Rules that catch people out:

• Integers go in as digits, never quoted. u32 becomes a JS number; 64-bit and wider types become big integers. Non-numeric input for a number field is rejected before the call.
• Address accepts both a G… account and a C… contract id, both are valid Soroban addresses.
• Bytes must be even-length hex. BytesN<32> must be exactly 32 bytes (64 hex chars); the field tells you if the length is wrong.
• Option<T> left empty is None. Type a value to send Some(value).
• Composite types are JSON. A Vec<u32> is [1, 2, 3]; an enum variant is its JSON object form.

Worked example#

A transfer(from: Address, to: Address, amount: i128) on a token contract:

from    GADTEST...XYZ        (Address)
to      GBQRST...UVW         (Address)
amount  500000000           (i128)

transfer requires the sender's authorization, so it's a write. Click Invoke & sign; the wallet signs and the transaction submits.

Reading the result#

The result panel shows:

• status, simulated for a read, success for a confirmed write.
• return value, decoded to JSON using the contract spec. A u32 comes back as a number, an Address as its string form, a struct as an object.
• resource fee, the fee paid, in stroops (writes only).
• tx hash, for a confirmed write, with a link to stellar.expert. Reads have no hash.
• events, any contract events emitted, decoded.

{ "status": "simulated", "returnValue": 2 }

{
  "status": "success",
  "returnValue": 3,
  "resourceFee": "00",
  "txHash": "a1b2c3…"
}

When it fails#

Errors are returned in plain language, not raw XDR:

A failed read or write is saved to your invocation history with the humanized error, so you can see what happened without re-running it.

Saved function tests#

Any call you run can be saved as a function test with an expected result, WebSoroban replays it by simulation and checks the return. See Test.

Next#

• Run unit and integration tests in Test.
• See the full type glossary in Reference.