TollcraftStop guessing your gas bill.

A three-tier cost awareness pipeline for Stellar smart contracts. Lint at compile time, assert at test time, profile when the budget fails — so every CPU instruction and storage byte is accounted for before mainnet.

Explore the Pipeline

Interactive Playground

Tier 1 — Prevent

Catch structurally expensive anti-patterns (storage in loops, redundant clones) before your code compiles using rustc and Dylint static analysis.

Cost Linter Docs →

Tier 2 — Detect

Simulate your contract against live network metering inside cargo test. Pin verified costs and fail CI before regressions hit on-chain.

Budget Assert Docs →

Tier 3 — Diagnose

When a budget fails, trace WASM execution instruction-by-instruction, map offsets back to Rust lines via DWARF, and inspect visual flamegraphs.

Cost Profiler Docs →

INTEGRATED WORKFLOW

Interactive Cost Lifecycle

Select a stage to inspect its role, runtime mechanism, and telemetry output.

PHASE 01 • COMPILE TIMErustc / Dylint driver

Eliminate structural cost anti-patterns before execution

Intercepts expensive patterns like storage mutations inside loops, redundant clone allocations, and unbounded recursion at build time with zero gas cost.

CRITICAL CAPABILITIES

▹40+ specialized Soroban AST and HIR lints
▹Detects blind storage writes and discarded reads
▹Flags TTL extension in loops and inefficient byte concat
▹Configurable severity (deny, warn, allow) via cargo config

cargo cost-lint --all-targets

warning: storage write inside loop
  --> contracts/pool/src/lib.rs:88:9
   |
88 |   env.storage().instance().set(&key, &val);
   |   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   = help: batch storage operations outside the loop
   = note: each write incurs 25k CPU instructions and ledger write fees

Explore soroban-cost-linter Documentation →

Unified Command Interface

Execute each tier through familiar Cargo subcommands with zero disruption to standard Rust workflows.

dev@tollcraft~/contracts/amm-pool$cargo cost-lint --all-targets

Building member crates for cost audit... warning: storage_in_loop detected --> contracts/amm-pool/src/lib.rs:94:13 | 94 | env.storage().instance().set(&key, &user_deposit); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ = help: batch storage writes outside the loop iteration = cost impact: ~25,000 CPU instructions + 1 ledger write entry per cycle [OK] Finished analysis in 0.42s (1 warning, 0 errors)

The Three Tiers of Cost Awareness

Tier 1: Prevent

Cost Linter

A static analysis shield for Soroban smart contracts. Hooks directly into rustc to catch expensive patterns before compilation.

Explore Cost Linter →

Tier 2: Detect

Budget Assert

An empirical runtime test harness. Measures network-simulated resource consumption and fails CI when budget limits are breached.

Explore Budget Assert →

Tier 3: Diagnose

Cost Profiler

Visual flamegraphs and execution tracing. Diagnoses exactly which functions, loops, and host operations burned your budget.

Explore Cost Profiler →

SOROBAN METERING MATRIX

Operation Cost Telemetry

Inspect how common contract operations translate into protocol-level resource consumption and fees.

Storage & I/OTier 1 Caught

Storage Write in Loop

Mutating instance or persistent storage on every loop iteration re-serializes entries and consumes non-refundable write fees per cycle.

CPU INSTRUCTIONS

~25,000 / iter

Host storage invocation & XDR serialization overhead

MEMORY FOOTPRINT

~512 B / iter

Intermediate host Val and key allocation

LEDGER I/O

1 Write / iter

Ledger key modified N times per transaction

RENT / TTL

Repeated TTL hits

Increases state contention on ledger entries

●HAZARDOUS PATTERN

for item in items.iter() {
    // [HAZARD] Incurs N writes and N host cross-calls
    env.storage().instance().set(&item.key, &item.val);
}

●OPTIMAL TOLLCRAFT PATTERN

let mut batch = env.storage().instance().get(&BATCH_KEY).unwrap_or(...);
for item in items.iter() {
    batch.push_back(item);
}
// [OPTIMAL] Commit once at loop completion
env.storage().instance().set(&BATCH_KEY, &batch);

GUARD

Tollcraft Protection:Linted at build-time by instance_storage_write_in_loop and asserted in tests via #[budget_write_bytes_lt].

The Cost of Soroban Operations

Soroban charges for every hardware resource your contract consumes on-chain under Stellar Protocol 22:

Resource Dimension	Unit of Measurement	Hard Cap (Per Tx)	Fee Impact
CPU Instructions	Executed instruction count	100,000,000 instructions	Non-refundable fee per million instructions
Memory Allocations	Bytes allocated / resident	40 MB	Enforced limit (execution fails on breach)
Ledger Entry Reads	Key-value pairs accessed	40 entries	Non-refundable fee per entry read
Ledger Entry Writes	Key-value pairs mutated	25 entries	Non-refundable fee per entry written
Ledger Read Bytes	Serialized payload bytes	~200 KB	Non-refundable fee per KB read
Ledger Write Bytes	Serialized payload bytes	~100 KB	Non-refundable fee per KB written
Ledger Space Rent	Byte × Ledgers duration	Dynamic	Dynamic refundable rent based on entry TTL

Every wasted instruction is a fee your users pay

Cost bugs don't fail standard unit tests — they silently inflate transaction fees in production. Use the Tollcraft pipeline to audit, gate, and diagnose your contracts before deployment.