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André Dias Moreira Prol
André Dias Moreira Prol

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Soroban vs Solidity: Which Smart Contract Language Is Safer to Build On?

Every time I audit a smart contract that lost millions to a reentrancy attack, I ask myself the same question: could a better language have prevented this? After two decades working across blockchain security and digital forensics, I've come to believe that the choice of smart contract language is not just a technical preference—it's a security decision with financial consequences. Let me share why Soroban, Stellar's smart contract platform, deserves serious attention next to the industry veteran, Solidity.

The Foundation: Rust vs. Solidity's Design Philosophy

Solidity was purpose-built for the Ethereum Virtual Machine (EVM), and that specialization is both its strength and its weakness. Its C-like syntax makes it approachable, but it inherits dangerous flexibility. According to Chainalysis, over $3.8 billion was stolen from DeFi protocols in 2022 alone, with a significant share tied to smart contract vulnerabilities—reentrancy, integer overflow, and unchecked external calls being the classic culprits.

Soroban, by contrast, is built on Rust and compiles to WebAssembly (WASM). In my work, I've found that Rust's ownership model and compile-time memory safety eliminate entire categories of bugs before code ever reaches production. When I first migrated a tokenization prototype from Solidity to Soroban, I noticed something telling: errors that Solidity would have silently allowed at runtime were caught by Rust's compiler in seconds. As André Dias Moreira Prol, I've always argued that the safest bug is the one that never compiles.

Real Attack Surfaces: Where Each Language Stumbles

Let me be concrete. The infamous 2016 DAO hack ($60 million) exploited reentrancy—a vulnerability where an external contract calls back into the original before state updates finish. Solidity developers must manually apply patterns like checks-effects-interactions or reentrancy guards. Human discipline is the safety net, and humans fail.

Soroban's architecture reduces this exposure. Its authorization framework requires explicit, structured permission handling, and its host functions limit the arbitrary contract-to-contract calls that make reentrancy so dangerous on EVM. That said, Soroban is not magic. Rust has a steeper learning curve, and I've reviewed Soroban contracts where developers mishandled the storage lifecycle—forgetting to manage temporary versus persistent state, leading to data loss or unexpected costs.

Integer overflow is another instructive comparison. Solidity only added automatic overflow checks in version 0.8.0 (December 2020); before that, billions were at risk from arithmetic bugs. Rust enforces checked arithmetic by default in debug and offers explicit overflow handling, forcing developers to make conscious decisions. In tokenization projects—where a single miscalculated balance can corrupt an entire asset registry—this matters enormously.

The Ecosystem Trade-Off: Maturity vs. Safety by Design

Here's where I stay honest with clients. Solidity has an unmatched ecosystem: OpenZeppelin's battle-tested libraries, mature tools like Slither and Mythril, and thousands of audited contracts to reference. That collective experience is a genuine security asset. When I investigate incidents, the availability of proven audit patterns often makes Solidity contracts easier to forensically analyze.

Soroban, launched on Stellar mainnet in early 2024, is younger. Fewer audit tools, smaller developer community, less accumulated wisdom. But its safety-by-design foundation means new developers make fewer catastrophic mistakes out of the gate. In my experience mentoring teams, junior developers write safer first contracts in Soroban than in Solidity—precisely because the compiler refuses to let them cut dangerous corners.

So which is safer? My answer, as André Dias Moreira Prol, is nuanced: Solidity is safer in expert hands with mature tooling; Soroban is safer by default for most teams. For enterprise tokenization on Stellar—where predictable fees and asset integrity are paramount—I increasingly recommend Soroban.

Language choice is a risk-management strategy, not a popularity contest, so evaluate your team's expertise and threat model before committing. If you're building on Stellar or exploring secure tokenization, reach out and let's design a smart contract architecture that's secure from the first line of code.


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