> For the complete documentation index, see [llms.txt](https://andrewkimjoseph.gitbook.io/celina-sdk/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://andrewkimjoseph.gitbook.io/celina-sdk/services/contractservice.md).

# ContractService

[**@andrewkimjoseph/celina-sdk**](/celina-sdk/api-reference/api-reference.md)

***

[@andrewkimjoseph/celina-sdk](/celina-sdk/api-reference/api-reference.md) / [services/contract.service](https://github.com/andrewkimjoseph/celina-sdk/tree/main/docs/api-reference/services/contract.service/README.md) / ContractService

## Class: ContractService

Defined in: [src/services/contract.service.ts:57](https://github.com/andrewkimjoseph/celina-sdk/blob/c35fe1db07a45a3cd14b2185df4abf2e6a2ec609/src/services/contract.service.ts#L57)

Read, gas-estimate, and prepare helpers for arbitrary contracts.

### Constructors

#### Constructor

> **new ContractService**(`clientFactory`): `ContractService`

Defined in: [src/services/contract.service.ts:60](https://github.com/andrewkimjoseph/celina-sdk/blob/c35fe1db07a45a3cd14b2185df4abf2e6a2ec609/src/services/contract.service.ts#L60)

**Parameters**

**clientFactory**

`CeloClientFactory`

**Returns**

`ContractService`

### Methods

#### callFunction()

> **callFunction**(`params`): `Promise`<{ `contractAddress`: `` `0x${string}` ``; `error?`: `undefined`; `functionName`: `string`; `network`: `"mainnet"`; `result`: `unknown`; `success`: `boolean`; } | { `contractAddress`: `` `0x${string}` ``; `error`: `string`; `functionName`: `string`; `network`: `"mainnet"`; `result`: `null`; `success`: `boolean`; }>

Defined in: [src/services/contract.service.ts:69](https://github.com/andrewkimjoseph/celina-sdk/blob/c35fe1db07a45a3cd14b2185df4abf2e6a2ec609/src/services/contract.service.ts#L69)

Simulate a read-only contract call (`eth_call`).

**Parameters**

**params**

[`ContractCallParams`](/celina-sdk/types/contractcallparams.md)

Contract address, ABI, function name, and optional args

**Returns**

`Promise`<{ `contractAddress`: `` `0x${string}` ``; `error?`: `undefined`; `functionName`: `string`; `network`: `"mainnet"`; `result`: `unknown`; `success`: `boolean`; } | { `contractAddress`: `` `0x${string}` ``; `error`: `string`; `functionName`: `string`; `network`: `"mainnet"`; `result`: `null`; `success`: `boolean`; }>

Decoded result on success; `{ success: false, error }` on revert

***

#### estimateGas()

> **estimateGas**(`params`): `Promise`<{ `contractAddress`: `` `0x${string}` ``; `error?`: `undefined`; `functionName`: `string`; `gasEstimate`: `string`; `gasPrice`: `string`; `network`: `"mainnet"`; `success`: `boolean`; `totalCost`: `string`; } | { `contractAddress`: `` `0x${string}` ``; `error`: `string`; `functionName`: `string`; `gasEstimate`: `string`; `gasPrice`: `string`; `network`: `"mainnet"`; `success`: `boolean`; `totalCost`: `string`; }>

Defined in: [src/services/contract.service.ts:114](https://github.com/andrewkimjoseph/celina-sdk/blob/c35fe1db07a45a3cd14b2185df4abf2e6a2ec609/src/services/contract.service.ts#L114)

Estimate gas for a contract call from `fromAddress`.

**Parameters**

**params**

[`ContractCallParams`](/celina-sdk/types/contractcallparams.md) & `object`

Same as `callFunction` plus required `fromAddress`

**Returns**

`Promise`<{ `contractAddress`: `` `0x${string}` ``; `error?`: `undefined`; `functionName`: `string`; `gasEstimate`: `string`; `gasPrice`: `string`; `network`: `"mainnet"`; `success`: `boolean`; `totalCost`: `string`; } | { `contractAddress`: `` `0x${string}` ``; `error`: `string`; `functionName`: `string`; `gasEstimate`: `string`; `gasPrice`: `string`; `network`: `"mainnet"`; `success`: `boolean`; `totalCost`: `string`; }>

Gas estimate, current gas price, and total cost in wei

***

#### prepareFunction()

> **prepareFunction**(`from`, `params`): `Promise`<[`SerializedPreparedFlow`](/celina-sdk/types/serializedpreparedflow.md)>

Defined in: [src/services/contract.service.ts:172](https://github.com/andrewkimjoseph/celina-sdk/blob/c35fe1db07a45a3cd14b2185df4abf2e6a2ec609/src/services/contract.service.ts#L172)

Build an unsigned single-step flow for a contract write (caller ABI). Calldata includes the CELINA attribution suffix. Rejects `view`/`pure` ABI entries.

**Parameters**

**from**

`` `0x${string}` ``

Sender wallet address (must match connected wallet when signing)

**params**

[`ContractCallParams`](/celina-sdk/types/contractcallparams.md)

Contract address, ABI, function name, optional args and wei `value`

**Returns**

`Promise`<[`SerializedPreparedFlow`](/celina-sdk/types/serializedpreparedflow.md)>

Single-step `SerializedPreparedFlow` for wagmi or MCP `executePreparedFlow`


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