Sandbox and devnet

How to use the sandbox

Every call to /api/rpc accepts an optional ?network=devnet query parameter. With it set, the proxy routes the request to devnet.helius-rpc.com instead of mainnet.

curl -X POST "https://demo.helius.dev/api/rpc?network=devnet" \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "getBalance",
    "params": ["4Nd1mYZBPe1xWXm1WjfttSrPArCxKt3MFGxYXmJ8wkYx"]
  }'

The response shape is identical to mainnet — only the data differs. Devnet has its own block height, validators, and accounts.

What devnet is good for

• Transaction simulation before risking mainnet
• End-to-end testing of wallet integration and signing flows
• CI runs that should not spend real SOL
• Demonstrating destructive operations (close account, burn tokens) safely
• Iterating on a new program deployed to devnet before mainnet rollout

What devnet is NOT good for

• Realistic performance testing — devnet validators run on smaller infrastructure
• Verifying third-party programs(Jupiter, Drift, MarginFi) that don't exist on devnet
• Testing things that depend on real token prices, real wallets, or real NFT marketplaces

Get devnet SOL

Use the official faucets:

• faucet.solana.com — 1 SOL per request, captcha-gated
• helius.dev/airdrop — Helius-hosted faucet

Or run the SDK's built-in airdrop:

// Request an airdrop on devnet
fetch("https://demo.helius.dev/api/rpc?network=devnet", {
  method: "POST",
  headers: { "Content-Type": "application/json" },
  body: JSON.stringify({
    jsonrpc: "2.0",
    id: 1,
    method: "requestAirdrop",
    params: ["<your-devnet-address>", 1_000_000_000]
  })
});

Note: the demo's allowlist may not include requestAirdrop for the shared key. If it returns -32005, hit a faucet instead.

For agents and CI runners

The OpenAPI spec at /openapi.json describes the network query parameter for the callRpc operation. Function- calling clients should expose network as an optional input on the generated tool and default to mainnet.

Helius devnet endpoint

If you have your own Helius API key, hit devnet directly without going through this proxy:

https://devnet.helius-rpc.com/?api-key=<your-key>