Custom Fuzz Testing for Blockchain Security
Our custom fuzzing proves what’s correct so you can ship with confidence.
Find more. Prove more. Ship secure.
Static analysis reveals what might go wrong — custom fuzzing proves what cannot break. FYEO builds bespoke fuzzing harnesses tailored to your exact codebase, extending traditional audits with stateful, dynamic verification that approaches mathematical assurance of correctness.
What is custom fuzz testing?
FYEO Custom Fuzz Testing is a framework and threat model that combines static analysis with bespoke fuzzing harnesses tailored to your codebase. We generate and mutate transactions, simulate adversarial users, and drive your protocol through thousands of stateful executions to uncover logic, math, and state-transition errors — while collecting evidence that your key security invariants hold.
Coverage across your stack includes
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Layer-1 Protocols – consensus, state transitions, validator logic, networking
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Smart Contracts – Solana, EVM, CosmWasm, Move, Sui, and more
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DeFi Protocols – AMMs, lending, governance, bridges
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Custom Runtimes – VMs, execution environments, interpreters
Why custom fuzz testing is critical
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Finds stateful and multi-step bugs that static analysis and unit tests miss
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Exercises realistic, adversarial input sequences across your full protocol surface
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Proves your invariants and math under extreme conditions, not just on paper
Key components of Custom Fuzz Testing
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Bespoke fuzzing harnesses built specifically for your protocol and threat model
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Stateful execution with shadow-state tracking and invariant checking
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High-coverage mutation strategies tuned to DeFi and protocol logic
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Reproducible seeds for every discovered issue and regression test
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Optional integration into CI to rerun fuzz suites on every release
Trusted by the world’s top Web3 projects and protocols
What you get with custom fuzz testing
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Custom fuzzing harnesses for your exact codebase and deployment assumptions
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Thousands of iterations with expected state verification and coverage insights
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Reproducible test cases for every bug and edge case we identify
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Detailed reports with verification evidence and remediation guidance
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