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Overview

The /v1/instructions/build endpoint enables direct control over contract interactions by specifying exact function calls. Users provide ABI signatures and arguments to generate MEE instructions with specific callData.

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How It Works

The build endpoint creates instructions by:
  1. Accepting function signatures - ABI-formatted function definitions
  2. Processing arguments - Including support for runtime balance checks
  3. Generating callData - Creates the exact contract call data for execution
This is the direct approach where users specify exactly what contracts to call and how, rather than expressing intents.

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Request Structure

POST /v1/instructions/build

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Request Body

ParameterTypeDescription
functionSignaturestringFunction signature (e.g., function transfer(address to, uint256 amount))
argsarrayFunction arguments, can include runtime balance objects
tostringTarget contract address
chainIdnumberChain ID for execution
valuestringOptional: Native token value in wei (default “0”)
gasLimitstringOptional: Gas limit for the transaction

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Runtime Balance Arguments

Arguments can include runtime ERC20 balance checks: 
{
  "type": "runtimeErc20Balance",
  "targetAddress": "0x742d35cc6639cb8d4b5d1c5d7b8b5e2e7c0c7a8a",
  "tokenAddress": "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913",
  "constraints": {
    "gte": "1000000",  // Greater than or equal to
    "lte": "10000000", // Less than or equal to
    "eq": "5000000"    // Equal to
  }
}

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Example Request

curl -X POST https://api.biconomy.io/v1/instructions/build \
  -H "Content-Type: application/json" \
  -d '{
    "functionSignature": "function transfer(address to, uint256 amount)",
    "args": [
      "0x742d35cc6639cb8d4b5d1c5d7b8b5e2e7c0c7a8a",
      {
        "type": "runtimeErc20Balance",
        "targetAddress": "0x742d35cc6639cb8d4b5d1c5d7b8b5e2e7c0c7a8a",
        "tokenAddress": "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913",
        "constraints": {
          "gte": "1000000"
        }
      }
    ],
    "to": "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913",
    "chainId": 8453,
    "value": "0"
  }'

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Response

Returns MEE instructions with the generated callData: 
{
  "instructions": [
    {
      "calls": [
        {
          "to": "0x833589fcd6edb6e08f4c7c32d4f71b54bda02913",
          "value": "0",
          "functionSig": "transfer(address,uint256)",
          "inputParams": [...],
          "outputParams": [...]
        }
      ],
      "chainId": 8453,
      "isComposable": true
    }
  ]
}

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Supported Argument Types

  • Address: EVM addresses (0x-prefixed, 40 hex characters)
  • BigInt: Large numbers as strings
  • Integer: Non-negative integers
  • Boolean: true/false values
  • Hex: Hex strings (0x-prefixed)
  • String: Regular text strings
  • Runtime Balance: Dynamic ERC20 balance checks with constraints
  • Arrays: Nested arrays of any supported type