Documentation Index

Fetch the complete documentation index at: https://docs.turnkey.com/llms.txt

Use this file to discover all available pages before exploring further.

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Overview

Traditionally, sending blockchain transactions onchain has been painful:

• You need to fund wallets with native gas tokens, creating onboarding friction
• Network congestion and fee spikes can cause transactions to stall or get dropped altogether

Turnkey reduces this to a couple of API calls. We handle fees and our battle-tested broadcast logic ensures inclusion even under adverse network conditions. You and your users never touch gas tokens or deal with stuck transactions.

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Supported chains

EVM (sponsored):

• Base - eip155:8453
• Polygon - eip155:137
• Ethereum - eip155:1
• Arbitrum - eip155:42161

EVM testnets (sponsored):

• Base (Sepolia) - eip155:84532
• Polygon (Amoy) - eip155:80002
• Ethereum (Sepolia) - eip155:11155111
• Arbitrum (Sepolia) - eip155:421614

Solana (sponsored):

• Solana mainnet - solana:mainnet
• Solana devnet - solana:devnet

Interested in another chain? Reach out to us!

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Construction and Broadcast

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EVM

A successful EVM transaction requires:

• Transaction construction: assembling the payload (recipient, value, calldata)
• Nonce: set correctly to order transactions and prevent conflicts
• Gas and tip fee: estimated to ensure inclusion even during network congestion
• Signature: cryptographically signing the transaction with the sender’s private key
• Broadcast: submitting the signed transaction to the network and monitoring for inclusion

Turnkey handles all of this for you via ethSendTransaction. Whether or not you use sponsorship, you pass through minimal payloads and we take care of the rest. We auto-fill any fields you omit. This endpoint supports arbitrary EVM transactions — not just simple sends. You can interact with smart contracts, deploy contracts, or execute any valid EVM operation.

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Solana

A successful Solana transaction requires:

• Transaction construction: assembling the list of instructions (program, accounts, data)
• Recent blockhash: fetched and attached at broadcast time to ensure the transaction is valid
• Compute unit limit: estimated and set to prevent failed transactions due to insufficient compute
• Priority fee: set to ensure timely inclusion under current network conditions
• Signature: cryptographically signing the transaction with the sender’s private key
• Broadcast: submitting the signed transaction to the network and monitoring for confirmation

Turnkey handles all of this for you via solSendTransaction. Whether or not you use sponsorship, you pass through a minimal payload and we manage the rest.

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Concepts

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Gas sponsorship (aka gas abstraction, gasless transactions, fee abstraction)

A single endpoint lets you toggle between standard and sponsored transactions. With sponsorship enabled, your users never need to hold native tokens to pay transaction fees — Turnkey covers them. Set sponsor: true to enable sponsorship, or sponsor: false to have fees paid by the sender’s wallet. Either way, Turnkey handles construction, signing, broadcast, and status monitoring. The sponsor flag only controls who pays the fee.

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Spend limits

Turnkey gives you USD-denominated controls over gas sponsorship spend at two levels:

• Organization-wide limit — the cap on total sponsored spend across your parent organization and all of its sub-organizations.
• Sub-organization limit — the cap that applies to each of your sub-organizations

What you can configure depends on your plan: You can set limit values and time intervals through the dashboard. You can also query current usage against the active limit via the get_gas_usage endpoint.

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Policy engine

You can write policies against both sponsored and non-sponsored transactions using Turnkey’s policy DSL:

• EVM: use the eth.tx namespace
• Solana: use the solana.tx namespace

This means you can seamlessly switch between sponsored and non-sponsored transactions and still use the same policies. Note: Turnkey sets all fee-related fields to 0 for sponsored transactions.

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Billing

Turnkey passes transaction fee costs through to you as a line item at the end of the month. You pay based on the USD value of fees at time of broadcast; Turnkey internalizes the inventory risk of token price changes. Our battle-tested fee estimation aims to be cost-efficient while ensuring quick transaction inclusion.

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Advanced

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Gas sponsorship smart contracts (EVM)

We could not find a satisfactory setup for gas sponsorship contracts that were both fast and safe, so we made our own. The contracts are open source and you can check them out on GitHub. Based on our benchmarks, these are the most efficient gas sponsorship contracts on the market. They achieve this through optimized logic, calldata encoding, and extensive use of assembly, which reduces gas overhead per sponsored transaction. The result: lower costs for you and faster execution for your users.

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Security

Some gas sponsorship setups by other providers are subject to replay attacks. If a malicious actor compromises the provider infrastructure, they can replay the gas sponsorship request multiple times with different nonces to create multiple transactions from a single request. At Turnkey, we never cut corners on security: we perform transaction construction in enclaves, and as long as the request includes the relevant nonce or blockhash, only one transaction can be created from it. Since the user’s authenticator signs requests and the enclave verifies signatures, a malicious actor cannot modify or replay the request. This is in line with Turnkey’s core system design principle: everything can be compromised outside of the enclaves and funds will still be safe. By default, our SDKs include a special gas station nonce for sponsored transaction requests.

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RPCs

Turnkey’s send transaction and transaction status endpoints eliminate the need for third-party RPC providers. You save costs and reduce latency because we holistically incorporate internal data and minimize external calls.

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Next steps

For implementation guides, see:

• Sending Sponsored EVM Transactions (React) - Using @turnkey/react-wallet-kit
• Sending Sponsored Solana Transactions (React) - Using @turnkey/react-wallet-kit
• Sending Sponsored Transactions - Using @turnkey/core directly