Best Rust Libraries for Solana Program Development in 2025

When you're writing a Solana program that processes thousands of instructions per second, library choices are not aesthetic decisions — they determine whether your program fits inside a compute unit budget, whether an auditor finds a zero-day in your arithmetic, and whether a rushed upgrade six months in causes a regression. This guide covers the Rust libraries that see real production use in on-chain programs in 2025, ranked by how often they actually move the needle.

Why Anchor Alone Is Not Enough

Anchor handles the boilerplate — account discriminators, deserialization macros, CPI helpers — and it does that well. But the moment your program involves token math, large accounts, or any non-trivial numerical computation, you need to reach outside the Anchor crate. The libraries below fill those gaps. Each one was chosen because it reduces either compute cost, audit surface, or the probability of a silent numeric error in production.

bytemuck — Zero-Copy Account Parsing at Zero Cost

bytemuck lets you interpret raw &[u8] slices as typed structs without allocating or copying. On Solana, where every try_borrow_data() call costs CUs and heap is limited to 32 KB per frame, this matters immediately for any program holding large state accounts.

The pattern is straightforward: derive Pod and Zeroable on your struct, then call bytemuck::try_from_bytes on the account data. You get a reference into the account's existing memory — no deserialization pass, no intermediate allocation. For a market-making program with per-market order books stored as fixed-size arrays in a single account, this consistently saves 20–40% of the CU budget compared to the equivalent AnchorDeserialize path.

Watch out for alignment. Padding bytes in your struct must be accounted for explicitly or the Pod derive will reject the type at compile time — which is the right outcome, because misaligned reads on-chain produce undefined behavior that auditors will flag.

Maintenance status: actively maintained, widely used across the Solana ecosystem including in official SPL programs. Zero concerns.

fixed — Deterministic Decimal Math Without Floating Point

Floating-point is banned on-chain. For anything involving price, fee, or rate calculations you need fixed-point, and rolling your own is where bugs live. The fixed crate gives you FixedI64, FixedU128, and the full family, with configurable fractional bits and arithmetic that panics predictably on overflow rather than silently wrapping.

In practice, I80F48 (80 integer bits, 48 fractional bits — the same layout used by Mango Markets internally) covers nearly all DeFi use cases: basis-point fee calculations, price ratios, and funding rates all fit without precision loss that would accumulate across a trading day.

Key trade-off: fixed types are not natively serializable by Anchor's AnchorSerialize. You either store them as their underlying i128/u128 and convert on access, or use a newtype wrapper. Both approaches add a line or two of boilerplate but keep the audit surface clean because the conversion boundary is explicit.

Maintenance status: stable, low churn, well-maintained. Used in production by several on-chain perpetual protocols.

spl-math — Overflow-Safe Integer Arithmetic

The spl-math crate from the Solana Program Library provides checked_* and precise_number utilities built specifically for SPL contexts. The headline feature is PreciseNumber: a 128-bit integer with a configurable decimal scale, designed for token amount math where you need to multiply large values without intermediate overflow.

Where fixed shines for rates and prices, spl-math is more natural for token-amount computations — calculating how many tokens to mint given a deposit, or computing a proportion of a vault's assets. The U256Checked wrapper is also useful when a single u128 multiplication would overflow before you divide.

One practical point: spl-math adds a dependency on spl-token indirectly. In a minimal program where you are not using the token program, fixed alone is cleaner. In a full DeFi program that already pulls in spl-token, spl-math pays for its dependency weight.

solana-program and spl-token — The Unavoidable Baseline

These are not optional reading — they are the substrate. A few specifics worth knowing beyond the obvious:

• invoke_signed CU cost is non-trivial. Batching CPIs (e.g., combining a token mint with a transfer in one instruction) measurably reduces total CU spend compared to two separate instructions from the client.
• spl-token-2022 introduced transfer hooks and confidential transfers. If you are writing a program that will interact with Token-2022 mints, audit every code path that assumes a transfer has no side effects — transfer hooks mean it may invoke arbitrary logic.
• The Rent sysvar access pattern changed in recent runtime versions; always derive rent from Rent::get() rather than passing it as an account, which avoids a deserialization cost and removes an account from your instruction's account list.

thiserror and num-derive — Error Handling That Auditors Love

Neither of these is Solana-specific, but they appear in every clean on-chain program for a reason. thiserror lets you define typed error enums with human-readable messages that survive across the RPC boundary into client-side error handling. num-derive with ToPrimitive/FromPrimitive gives you safe, zero-cost conversion between your error enum and the u32 error codes the Solana runtime requires.

The alternative — returning raw ProgramError::Custom(N) with magic constants — creates audit friction. Reviewers have to chase down what Custom(7) means. An error enum with thiserror attributes makes every revert path self-documenting, which shortens audits and helps operators triage on-chain failures faster.

When to Reach for Each

Situation	Reach for
Large account with many fields, CU budget tight	bytemuck zero-copy
Price, rate, or fee math	fixed (I80F48 or similar)
Token amount proportions, mint math	spl-math PreciseNumber
Token-2022 compatibility	spl-token-2022 with transfer hook awareness
Typed, debuggable on-chain errors	thiserror + num-derive

The programs we build at TierZero — whether it's an MEV arbitrage engine or a custom on-chain market maker — use all of these together. None of them are exotic. They are table stakes for programs that run in production under real economic pressure and survive audits.

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If you're building a Solana program and want it written by engineers who run these dependencies in production, reach out — we scope and build on fixed timelines.