Understanding Prepare Transactions and Blockchain Fees APIs

Developers and businesses are increasingly integrating cryptocurrency functionality into their platforms. Whether it's enabling wallet transfers, NFT minting, or smart contract interactions, blockchain transactions are at the heart of Web3 experiences.

However, sending a blockchain transaction isn't as simple as clicking a button. Behind the scenes, developers must estimate gas fees, construct valid transactions, and sign them securely before broadcasting to the network. This complexity is where Prepare Transactions APIs and Blockchain Fee Estimation APIs come in.

In this article, we'll explore how these tools streamline crypto development, reduce risk, and make apps more responsive and reliable. We'll also walk through a practical example to show how they work in tandem.

What Is a Prepare Transactions service?

Prepare Transactions API is a service that helps developers create a ready-to-sign blockchain transaction. It simplifies the steps involved in building a transaction by:

• Collecting input parameters (e.g., from/to addresses, token amount)
   
• Validating inputs and formatting data
   
• Suggesting appropriate gas or fee settings
   
• Generating a transaction payload that can be signed with a private key

The result is a transaction object that’s ready to be signed and broadcast to the blockchain network.

Why It Matters:

Without this API, developers would need deep protocol-level knowledge to manually construct transactions. This often leads to errors, rejected transactions, or funds getting stuck due to underpaid gas fees.

What Are Blockchain Fee Estimation service?

Every blockchain charges network fees (gas, in Ethereum terminology) to process transactions. These fees fluctuate based on network congestion and transaction complexity.

A Blockchain Fee Estimation API provides real-time data on:

• Current fee tiers (low, medium, high priority)
   
• Estimated confirmation times for each tier
   
• Recommended gas price or fee multiplier for different use cases

These APIs are especially useful in:

• Wallet apps
   
• Crypto exchanges
   
• NFT platforms
   
• DeFi dApps

By using them, applications can offer users cost transparency and faster transaction execution.

The Workflow: How Prepare and Fee APIs Work Together

Let’s break down a typical workflow in four steps using these APIs.

Step 1: Estimate Network Fees

Before building the transaction, the app queries a Blockchain Fee Estimation API to get current fee rates. Based on the user’s urgency, the app can choose a fee tier (e.g., fast, standard, economical).

Step 2: Prepare the Transaction

With fees in hand, the app calls the Prepare Transactions API, passing in:

• Sender and recipient addresses
   
• Amount or token to transfer
   
• Chosen fee/gas level
   
• Network and blockchain type (e.g., Ethereum, Polygon, Bitcoin)

The API returns a transaction payload that is:

• Validated
   
• Optimized for the selected fee tier
   
• Ready for digital signature

Step 3: Sign the Transaction

The app or user signs the transaction using a secure method:

Local private key (for non-custodial wallets)

• Transactions must be signed locally on the client side for security.
   
• The private key stays on the user’s device and is never shared.
   
• The user must ensure they have the tools needed to sign the transaction.
   
• A signed transaction can be safely sent to the network.

Step 4: Broadcast and Monitor

Finally, the signed transaction is sent to the network using a broadcast endpoint. Apps often use webhook or polling features to monitor the transaction status until it's confirmed.

Real-World Example: Sending ETH with Optimal Fees

Let’s say a crypto wallet app wants to send 0.5 ETH from User A to User B on Ethereum:

1. Get Fees:
   
   
   • Call the Blockchain Fee API
      
   • Response:
     
     
     • Low: 18 Gwei (~3 mins)
        
     • Medium: 22 Gwei (~1 min)
        
     • High: 28 Gwei (~15 secs)
2. Prepare Transaction:
   
   
   • Set fee to Medium (22 Gwei)
      
   • Pass addresses and amount to the Prepare Transactions API
      
   • API returns a hex-encoded, signed-ready transaction payload
3. User Signs:
   
   
   • The app uses a connected wallet to sign the payload
4. Broadcast:
   
   
   • App sends the signed transaction using a broadcast endpoint
      
   • Monitors transaction status and sends webhooks to confirm whether it succeeded or failed.

Benefits for Developers and Businesses

1. Faster Development Cycles

By using APIs to abstract complex blockchain operations, teams can launch features faster with fewer bugs.

2. Improved User Experience

Users are less likely to abandon transactions when fees are transparent and optimized for their goals.

3. Fewer Failed Transactions

APIs ensure proper formatting, nonce handling, and gas estimation—reducing failed or stuck transactions.

4. Multi-Chain Flexibility

Many services support Ethereum, Bitcoin, Polygon, BNB Chain, and more—ideal for cross-chain apps.

Build Smarter, Not Harder with our APIs

Understanding and optimizing blockchain transactions is critical to building reliable crypto apps in 2025. By using Prepare Transactions and Fee Estimation APIs, developers can simplify the transaction flow, minimize user friction, and ensure every transaction reaches the blockchain quickly and securely.

These APIs are essential tools for any platform looking to scale its blockchain operations while delivering a seamless experience to end users.