In an increasingly dynamic blockchain universe, The Open Network (TON) stands out through its speed, scalability, and robust Telegram integration. Whether you are building a decentralized app (dApp), Telegram bot with blockchain, or Web3 company, it is your TON development team experience that will either shatter or make your project. With growing competition and the evolution of the TON ecosystem, it is more important than ever to employ developers with deep technical expertise and practical development experience. If you are genuinely in need of hiring TON developers, these 10 must-ask technical questions help to reach the final decision.
1. What is the TON Virtual Machine (TVM), and how is it different from the Ethereum Virtual Machine (EVM)?
TON Virtual Machine, or TVM, is the main runtime environment for The Open Network’s smart contracts. TVM is a stack machine specifically crafted to take full advantage of the new cell-based data structure of TON that enables the performance and scalability of the network. TVM executes smart contracts written in programming languages such as FunC and Tact and compiles them to very highly optimized binary logic cells that directly communicate with the blockchain of TON.
Unlike the register-based Ethereum Virtual Machine (EVM), which is particularly well-adapted to Ethereum’s account model, TVM is message-passing and sharding-oriented and therefore particularly well-adapted to TON. This raises the following main differences:
- Stack-Based Computation: TVM is stack-based, and computation is carried out by making use of a stack of values. This is different from EVM’s register-based computation and demands that developers deal with data manipulation and storage during contract execution in a different way.
- Deterministic Execution: TVM ensures the execution of all smart contracts is deterministic, i.e., the contract will always produce the same output for a given input. This is essential for security and consensus in a decentralized network.
- Cell-Based Storage: TVM directly interacts with TON’s cell-based storage, a hierarchical and highly efficient data structure that provides such sophisticated features as dynamic sharding and parallel processing. Developers must understand how to store and retrieve data in these cells to develop high-performance contracts.
- Gas Metering Logic: TVM also differs from EVM in gas metering logic. Gas costs are calculated based on the specific operations and storage used within the TON ecosystem, which can affect how contracts are optimized for cost.
- Compilation to Logic Cells: TON compiles smart contracts into binary logic cells, which are run by the TVM. This is unlike EVM bytecode and requires a close familiarity with TON’s compilation and deployment pipeline.
A seasoned TON developer would have these differences down pat, describing how TVM architecture affects the architecture and implementation of smart contracts, and demonstrating first-hand experience in contract writing, optimization, and deployment on the TON network. He or she would know the intricacies of FunC and Tact and understand how to leverage TVM features for building secure, scalable, and performant decentralized applications.
2. Which languages are used for smart contracts in TON?
The two main languages for developing smart contracts on TON are:
- FunC – A low-level C-like language that provides high-level control over contract logic and resource management. FunC is suitable for developers who must optimize for performance and efficiency, and thus is best suited for involved or resource-intensive contracts.
- Tact – A higher-level, developer-focused language that compiles to FunC. Tact simplifies development using novel syntax and abstractions to allow developers to write secure, simple-to-maintain contracts more effectively.
Highly talented TON developers must be fluent in both languages and understand when to employ which one, depending on the project complexity, performance expectations, and maintainability. Execution of critical logic necessitates knowledge of FunC, whereas Tact is used for faster development of most typical use cases.
3. Can you explain the concept of cells and slices in TON?
Cells are the simplest data structure in TON and the foundation of its storage and communications systems. A cell is a vertex of a DAG with at most 1023 bits of data and references to at most four other cells. The data structure allows for dense storage of data, scalable and flexible.
Slices are read-only references to the data in a cell so that programmers may read segments of a cell without duplicating the data. Slices allow parsing and processing of deeply nested data structures with high performance, as is needed for contract logic as well as for message processing.
Any seasoned TON developer must know slices and cells well because these are the components of everything, ranging from permanent storage to message passing and contract execution in the network. Good knowledge of such structures enables developers to create fault-tolerant, scale-out, and cost-effective decentralized applications on TON.
4. How is state maintained across transactions in TON smart contracts?
TON smart contracts do not maintain state between calls, as with some other blockchain platforms. There will be a need for developers to serialize and store contract state by hand using storage cells, holding onto any variables or datathath must be persisted by placing it into storage on transaction completion. When a contract makes its second call, it will deserialize the state out of stored cells to continue where it stopped.
A skilled programmer will elucidate that they:
- Cache variables between calls by serializing them into cells and maintaining the contract’s permanent storage up-to-date.
- Supply initialization state and bounced messages to allow contracts to recover from a failed transaction or re-initializations with less inconvenience.
- Minimize data redundancy with clever data structures and by not storing redundant data, saving gas and performance.
- Use strong error checking and state validation to guarantee contract correctness for a high volume of transactions.
State management plays a critical role in secure and reliable TON smart contract development since it can cause data loss, attacks, or even unexpected behavior if not properly managed.
5. How are cross-contract calls executed in TON?
Cross-contract calls in TON are supported by the network’s message-passing infrastructure, being central to how contracts communicate and behave with each other. A good response would include:
- How internal messages (sent from one contract to another contract within the blockchain) differ from external messages (sent to or from the outside of the blockchain, i.e., user wallets or other systems).
- The use of bounceable and non-bounceable flags determines if a message is to be returned to the caller in case the receiving contract cannot process it. This helps manage errors and prevent loss of money or information.
- The structure of the message payload, including serialized data, and how gas is communicated, so the receiving contract has enough means of processing the call.
- Implication of asynchronous execution as the messages are processed sequentially and not necessarily under the same transaction.
These mechanisms have to be graspedtoo create dApps using multiple smart contracts for facilitating smooth communication, proper error handling, and proper resource management within the TON environment.
For a closer examination of real-world applications of these mechanisms in action, examine how teams like TheRaven have built robust multi-contract systems on the TON blockchain.
6. What security practices do you follow in TON smart contract development?
Security is of the utmost importance in TON smart contract development due to the financial and inherently irrevocable nature of blockchain transactions, such that it is critical to ensure contracts are secure against exploit and attack. Developers have to pay attention to a range of security best practices, including:
- Preventing reentrancy attacks via proper management of external calls and state changes before any external interaction.
- Message signature verification to ensure the authenticity of the source and integrity of received messages, to prevent unauthorized activities or spoofing.
- Protection of gas limits to prevent denial-of-service (DoS) attacks, to keep contracts from being used by attackers to maliciously consume resources.
- Defense against logical vulnerabilities via storage cells through intense data integrity checks, cell reference management in a safe manner, and protection against accidental reveal or overwrite of data.
- Access controls and permission checks to restrict sensitive operations to authorized users or contracts.
- Active auditing and manual and automated code review, on a regular schedule, to identify and minimize probable vulnerabilities before deployment.
A good programmer should be able to demonstrate good development practices, using examples straight from actual projects, and be ever proactive regarding smart contract security throughout the entire process. Consider this: over 66% of backlinks on the internet are dead links. It’s not just old or poorly maintained websites—smart contracts with poor error handling, fallbacks, and defensive programming are just as toast. In TON’s fast-paced universe, a tainted dApp is waiting to happen. Don’t make your product one of them—precode, severity test, and miss a small condition in code, and you’ll lose everything.
7. How do you test and debug smart contracts before deployment?
A solid testing and debugging cycle is required to maintain the security and trust of TON smart contracts. The next cycle is regarded as follows:
- Using in-local development environments such as func, tact, or ton-emulator as an emulation of contract usage and detecting issues ahead of time in development.
- Delivering comprehensive unit tests, most likely in JavaScript or TypeScript, using tools such as ton-core to test contract logic, edge cases, and error behavior.
- Executing contracts on the TON testnet to conduct live-like integration testing, allowing developers to observe contract execution happen under real network conditions and interact with other contracts deployed. Using debugging tools and log analysis to monitor execution flows, observe state changes that happen, and debug unforeseen bugs or crashes.
- Refining code continuously based on test outcomes, code peer review, and comments from the testnet release to maximize reliability before live release on the mainnet.
Automated testing technical skill is a good predictor of code reliability and quality, and professional developers can define their automated testing process, continuous integration, and optimal techniques for bug-catching before production release.
8. What is your approach to upgrading smart contracts on TON?
Tone smart contract upgrades are challenging in a unique way, as the platform is not natively suitable for designs like Ethereum proxies. Other solutions must be employed for contracts to be made flexible by developers without compromising security or trust with users. Safe solutions include:
- Employing state migration contracts that propagate persistent data from a contract to the next version, preserving user balances, access permissions, and other important information for upgrades.
- Separating business core logic from the underlying contract pieces and applying message-based routing to pass calls to the latest logic contracts. Modular composition facilitates selective upgrading and reduces the exposure of vulnerabilities to migrations.
- Rolling out the contracts with backward compatibility, so that updates don’t render older users or integrations obsolete. That can include running older interfaces or contract versions in parallel, too.
- Having good upgrade mechanisms in place, with good testing, documentation, and open communication with users, to minimize risks and make the ride smooth.
- Considering governance controls or multi-signature upgrades, which add an extra layer of security and trust.
A seasoned TON developer can go in-depth on these methods, include some practical examples, and display an apparent consideration style of contract writing in a decentralized environment.
9. Have you worked with TON DNS, TON Storage, or TON Proxy?
TON has a set of built-in services that enormously extend the capabilities of decentralized applications. Familiarity with these services is a positive indicator of the flexibility and ability of a developer to create feature-rich solutions:
- TON DNS supplies human-readable blockchain addresses and allows one to use wallets and smart contracts without managing long hexadecimal strings. Developers should be aware of how to register, resolve, and employ TON DNS domains within applications.
- TON Storage enables decentralized hosting of data, and it is made possible with it to host and retrieve files, metadata, or even large datasets in efficient and secure ways. Constructing censorship-resistant and scalable apps with proficiency in TON Storage.
- TON Proxy offers anonymous and secure data forwarding, something that is essential for privacy applications and avoiding network constraints. The authors should be able to show how TON Proxy can be used to enhance user anonymity and application robustness.
An experienced TON developer would not only be familiar with such services but also have practical experience in combining them to solve real issues, enhance user experience, and unleash new capabilities in the TON universe.
10. How do you integrate a TON-based smart contract with Telegram or a frontend?
In deploying a TON-based smart contract using Telegram or a web-based interface, it is required to demonstrate experience working with new tools and best practices within the field. Some of the most critical knowledge areas are:
- Using ton-connect for wallet integrations safely, allowing users to use smart contracts from their wallets without compromising privacy and security. Developers must be comfortable triggering wallet connections, managing authentication flows, and transaction signing.
- Building secure Telegram bots that interact with smart contracts in a bid to allow users to trigger on-chain activity, get real-time notifications, and manage assets directly from the Telegram interface. This requires a solid understanding of both the Telegram Bot API and TON’s messaging stack.
- Building inline web applications that marry hand-in-glove with on-chain activity, with accessible experiences where blockchain interactions are concealed beneath familiar web or mobile interfaces. Frontend framework abilities, smart contract APIs, and frontend-blockchain secure communication abilities are needed by developers.
- Offering end-to-end security and usability, with proper error handling, user feedback, and phishing or adversarial interaction resistance.
- Demonstrating knowledge of cross-platform deployment and responsive design to enable accessibility across devices.
An experienced TON developer at a senior level would be able to demonstrate real-world integrations, describe architecture decisions, and indicate how they connect the dots between blockchain infrastructure and user-facing applications.
Final Thoughts
There aren’t many “blockchain developers” who are TON-ready. It is a different architecture than Ethereum with distinct tooling, distinct logic, and distinct execution models. The incorrect developer will take your time, burn your budget, and possibly even endanger your users.
The correct developer will:
- Be familiar with TVM and FunC inside and out, having conquered the intricacies of TON’s execution environment and contract languages.
- Write gas-optimized, secure, and TON architecture-specific vulnerability-free smart contracts that are economical.
- Integrate natively with Telegram, TON DNS, TON Storage, and other native applications, making the whole ecosystem’s feature set available in your application.
- Use battle-tested patterns in testing, state management, and cross-contract messaging, and develop reliability and scalability from the start.
- Stay current with recent updates in the TON ecosystem and continually enhance their skill set and adopt best practices along with the changing platform.
- Communicate clearly and concisely, with transparency, to provide clarity during development as well as efficient collaboration with your team.
By asking the right questions and seeking out developers with genuine TON expertise, you’ll position your project for long-term success in one of the most innovative blockchain ecosystems today.
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