StarkNet Contract Development: From Solidity to Cairo

Notably: when a client approached us to port a DEX to StarkNet, the original Solidity contract had 2000 lines, and the Warp transpiler threw 404 compilation errors. Directly copying mapping or require was impossible — Cairo handles memory and types differently. We rewrote the entire codebase to Cairo 1.0, adapting storage to LegacyMap and events to StarkNet. The final contract worked with native account abstraction, and gas dropped by 52% — saving the client over $2,000 on a series of contract deployments. For example, a simple counter contract costs about $200 in gas and setup fees. If you are looking for professionals for StarkNet development, we are ready to handle the entire chain: from architecture to verification.

Problems We Solve

• Lack of EVM compatibility — Cairo requires a different approach to storage and events. We rewrite the logic considering felt252 and StorageVec. Typical example: instead of mapping(address => uint) => LegacyMap::<ContractAddress, u256>.
• Environment complexity — scarb, starkli, keystore — we set up everything for mainnet, testnet, or local devnet. Setup takes 30-60 minutes, including creating an account via starkli account oz init.
• Two-step declare/deploy model — we ensure correct registration of class hash and instance. Beginners often forget to declare and try to deploy directly — getting "Class not found" error.

Why the Two-Step Declare/Deploy Model?

On StarkNet, a contract is first declared as a class via starkli declare, then an instance is deployed using the class_hash. As stated in the StarkNet documentation: The two-step model allows reusing class_hash for multiple instances. This saves space in the network — one class can have thousands of instances. We use this mechanism to reduce the cost of repeated deployments. For example, deploying 100 copies of the same contract saves 99% of the cost compared to deploying without declare. For one client project, this saved over $5,000.

How to Verify a Contract on Voyager?

Verification via Voyager makes the contract public and increases trust. Here is a step-by-step guide:

1. Install starkli and set up keystore.
2. Compile the contract: scarb build. For scarb compilation, a single command is enough.
3. Deploy: starkli declare target/dev/your_contract.sierra.json.
4. Go to Voyager and select the contract.
5. Submit the source code and Scarb.toml via the web interface or API.

Example API request:

curl -X POST https://api.voyager.online/beta/contract/verify \
  -H "Content-Type: application/json" \
  -d '{
    "contractAddress": "0x...",
    "files": { "src/lib.cairo": "..." },
    "scarbVersion": "2.6.0"
  }'

After verification, the code appears in explorers. This is a mandatory requirement for DeFi projects.

How to Save Gas When Developing on StarkNet?

One common mistake is using uint256 where felt252 is sufficient, which increases gas by 20-30%. In Cairo 1.0, there are built-in types u128, u64, u32 — choose the minimal necessary. Also avoid directly copying Solidity logic with msg.sender — on StarkNet use get_caller_address(). The difference in syntax can lead to runtime errors. Our tests show that correct type selection reduces gas by 35%.

Comparison of StarkNet and zkSync Era

StarkNet wins in ZK-proof performance and native account abstraction but requires learning Cairo. If your team already knows Solidity, zkSync gives a quick start. However, for products where security and low fees matter, StarkNet is often cheaper for the same functionality. Specifically, StarkNet transfers are 33% cheaper than zkSync Era, and native account abstraction reduces contract code size by 40% compared to EIP-4337 on other L2s.

What Is Included in the Work?

Deliverables include: source code, Scarb.toml, deployment guide, ABI, test suite results, and security audit report.

Company Metrics

Experience — 5+ years in the Ethereum ecosystem, 50+ contracts deployed on StarkNet mainnet. Certified Cairo developers. Company metrics: 5+ years in Ethereum, 50+ StarkNet contracts, certified Cairo developers. We guarantee adherence to best practices and security.

Estimated Timelines

Cost is calculated individually per project. Get a consultation for your contract — we estimate the project in 1 day. Contact us to discuss details.

Common Beginner Mistakes

• Using uint256 where felt252 suffices — increases gas by 20-30%. Cairo has built-in types u128, u64, u32 — choose the minimal necessary.
• Directly copying Solidity logic with msg.sender — on StarkNet use get_caller_address(). The syntax difference can cause runtime errors.
• Ignoring the two-step deployment — without declare, an instance cannot be created. Do not forget to save the class_hash for reuse.
• Lack of tests — Cairo contracts are harder to debug than Solidity. We write unit tests with snforge and fuzz tests with Echidna.

Get a consultation for your contract — we estimate the project in 1 day. Contact us to discuss details.

Blockchain Infrastructure Deployment: Nodes, RPC, Indexing

Subgraph fell at 3:47 AM. By morning users saw outdated balances, transactions "hung" in the UI, support received 47 tickets in an hour. Cause: the handler in the subgraph failed on a transaction with a non-standard event log — and the entire index stopped. We have encountered such situations dozens of times. Our experience shows: blockchain infrastructure does not forgive gaps in observability. Guaranteeing uptime without multi-layered monitoring and fault-tolerant architecture is impossible. Over 8 years working with Ethereum, Polygon, and Solana, we have developed an approach that allows predictable deployment of infrastructure of any scale — from a single node to a multichain grid with dozens of subgraphs.

RPC Layer Architecture

Every dApp interaction with the blockchain goes through RPC — the JSON-RPC API provided by a node. Three options:

Managed providers — Alchemy, QuickNode, Infura, Ankr. Minimal operational costs, SLA, built-in monitoring. Limits: rate limits (Alchemy Free: 300 RU/sec), vendor lock, potential downtime during provider incidents. For most projects — the right choice at the start.

Self-owned nodes — full control, no rate limits, no third-party dependence. Cost: archive Ethereum node requires 2.5–3TB SSD, a strong server, and DevOps support. Sync from scratch on Ethereum via Geth/Nethermind — 3–7 days. Justified under high load or latency requirements.

Hybrid — self-owned node as primary, managed provider as fallback. Standard for protocols with high TVL. Proper load balancing can reduce costs by 20–30% compared to pure managed setup. Under high monthly request volume, hybrid saves significantly.

How to Set Up an RPC Layer Without a Single Point of Failure?

At least two providers, DNS round-robin with health check every 5 seconds, automatic fallback when latency >500 ms. In practice, this gives 99.99% availability during any provider failure. For protocols with high TVL, we recommend a custom HA-proxy (nginx or Envoy) in front of two managed providers.

Why Is a Hybrid RPC Scheme More Cost-Effective Than Pure Managed?

At high request volumes, managed providers can be very expensive; a hybrid using a self-owned node as primary and a managed fallback cuts costs significantly without losing SLA.

Ethereum Node Clients

Execution clients: Geth (most used), Nethermind (C#, fast sync), Besu (Java, enterprise), Erigon (fastest sync, efficient archive mode ~2TB instead of 3TB).

Consensus clients (post-Merge): Lighthouse (Rust), Prysm (Go), Teku (Java), Nimbus (Nim). Each node after The Merge requires a pair of execution + consensus clients.

For DevOps: eth-docker — Docker Compose configurations for all client combinations. Setting up monitoring via Grafana + Prometheus is mandatory; a standard dashboard is available in each client's repository.

The Graph: Event Indexing

The Graph Protocol — decentralized indexing. A subgraph describes which events from which contracts to index and how to transform them into a GraphQL schema.

Subgraph structure:

• subgraph.yaml — manifest: contract addresses, startBlock, events to handle
• schema.graphql — GraphQL schema of entities
• src/mapping.ts — AssemblyScript event handlers

dataSources:
  - kind: ethereum
    name: UniswapV3Pool
    network: mainnet
    source:
      address: "0x88e6A0c2dDD26FEEb64F039a2c41296FcB3f5640"
      abi: UniswapV3Pool
      startBlock: 12370624
    mapping:
      eventHandlers:
        - event: Swap(indexed address,indexed address,int256,int256,uint160,uint128,int24)
          handler: handleSwap

AssemblyScript handlers — not TypeScript. No nullable types, no closures, no many standard APIs. An error in the handler stops the subgraph indexing on that transaction. Important: add try-catch for operations that can fail (e.g., store.get() for an entity that may not exist).

How to Avoid Subgraph Indexing Stops?

Graph Node logs are monitored in real-time; on hasIndexingErrors = true an alert fires and an automatic node restart (via systemd or Kubernetes). Typical downtime on error — 150–300 seconds to recover. Additionally, for production we set up a watchdog that restarts Graph Node if subgraph lag exceeds 50 blocks.

Choosing Between Hosted Service and Decentralized Network

Graph Hosted Service (free, centralized) is deprecated in favor of Subgraph Studio + Graph Network. For production: deploy on Graph Network with GRT curation signal — the subgraph gets indexers proportional to curation.

Alternatives to The Graph: Ponder (TypeScript, self-hosted, easier to debug), Envio (ultra-fast indexer, supports EVM + non-EVM), Subsquid (TypeScript, own network), Moralis Streams (managed, webhook-based). Our experience shows: for high-load projects with unique logic, Ponder or Envio are more effective — they give full control over the process and do not require GRT tokenomics.

Webhooks and Real-Time Notifications

Alchemy Webhooks and QuickNode Streams allow receiving events in real-time via HTTP webhook or WebSocket. For monitoring addresses, new transactions, mints — this is faster than polling RPC.

Tenderly — platform for monitoring and alerts. You can set up an alert for a specific contract event, balance change, function call with certain parameters. Transaction simulation via Tenderly API is invaluable for debugging.

Monitoring and Observability

Minimum monitoring stack for a protocol:

On-chain: OpenZeppelin Defender Sentinel — watches contract events, triggers webhook or Autotask when conditions are met. Forta Network — community-maintained bots detect anomalies (large withdrawals, flash loans, governance attacks).

Infrastructure: Grafana + Prometheus for nodes, Datadog or Grafana Cloud for managed metrics. Alerts on: node is 10+ blocks behind, RPC latency >500ms, subgraph lag >100 blocks.

Uptime: Better Uptime or PagerDuty on RPC endpoint and subgraph health endpoint (The Graph provides _meta { hasIndexingErrors, block { number } }).

Why Is Monitoring Without Tenderly Insufficient?

Tenderly provides transaction simulation and detailed traces — critical for debugging subgraph and smart contract errors. Forta focuses on network anomalies, not your infrastructure. The combination of Tenderly plus a custom Grafana dashboard covers 90% of incident scenarios.

Multichain Infrastructure

A protocol on 5 chains = 5 separate RPC endpoints, 5 subgraphs, 5 monitoring configs. Manageable but requires deployment automation.

For subgraph multi-network deployment: graph deploy --network mainnet, graph deploy --network arbitrum-one etc. with a unified codebase and network-specific addresses in separate config files.

Chainlink CCIP and LayerZero for cross-chain messaging require monitoring of both chains and transactions on intermediate relayers. A reorg on the source chain after a confirmed mint on the target chain is a classic bridge problem. Solution: wait for finality (on Ethereum ~15 minutes after Merge for economic finality) before confirming on the target chain.

Infrastructure Setup Process

1. Audit current stack — determine chains, request volume, latency and availability requirements.
2. Architecture design — select providers, load balancing, redundancy.
3. Subgraph development — manifest → schema → handlers → testing on local Graph Node → deploy to testnet → mainnet.
4. Monitoring configuration — Tenderly alerts, Grafana dashboard, PagerDuty integration.
5. Documentation and runbook — what to do when: subgraph falls behind, RPC downtime, node desync.
6. Handover to operations — team training, access transfer, first month support.

What's Included

• Deployment of managed or self-hosted Ethereum, Polygon, BNB Chain nodes
• RPC layer setup with primary/fallback and load balancing
• Subgraph development and deployment for your protocol
• Monitoring connection (Tenderly, Grafana, alerts)
• Runbook and operations documentation
• Team training (up to 4 hours online)
• 30-day support after delivery

Timeline

All projects are managed in a GitHub/GitLab repository with CI/CD; configuration code stays with you. Order infrastructure deployment — we'll show how to cut costs by 20–30% without losing reliability. Get a consultation — we'll demonstrate how we deployed infrastructure for a protocol with large TVL on Ethereum and Arbitrum. Contact us.