RentBack

RentBack is a public utility for scanning token accounts on Solana and showing read-only excess rent currently reclaimable from each account.

This first iteration intentionally stops at:

1. address validation
2. on-chain read-only scanning for SPL Token and Token-2022 token accounts
3. rent projection math and projections UI
4. no wallet connection and no WithdrawExcessLamports execution

What it does (today)

• Validates a provided Solana wallet address.
• Scans both SPL Token and Token-2022 accounts for that owner.
• Reads each account’s actual account size and lamport balance.
• Queries getMinimumBalanceForRentExemption by unique size from RPC.
• Computes claimable claimable lamports using bigint arithmetic.
• Displays current claimable totals and phase projections:
  • phase 2 expected unlock
  • final phase (phase 5, planned 90% reduction) unlock
• Excludes wrapped/native SOL token accounts from claiming logic.
• Renders a dark single-screen UI with account details in a collapsible section.

Tech stack

• Next.js App Router (TypeScript)
• Tailwind CSS
• @solana/kit
• @solana/react
• @solana/kit-plugin-rpc
• @solana/kit-plugin-wallet
• @solana-program/token
• @solana-program/token-2022

Configuration

Set SOLANA_RPC_URL in your environment for a custom RPC endpoint. Keep production credentials in server-side environment only.

SOLANA_RPC_URL=https://mainnet.helius-rpc.com/?api-key=YOUR_KEY

Do not commit secrets.

Validation

• Unit tests cover bigint rent/excess calculations and wrapped-native exclusion.
• The project includes:
  • pnpm test
  • pnpm lint
  • pnpm typecheck
  • pnpm build

Project structure

• src/app/page.tsx: scanner UI
• src/app/api/scan/route.ts: server-side scanner endpoint
• src/lib/solana/scan.ts: read-only scan orchestration
• src/lib/rent-calculations.ts: bigint rent/projection helpers
• src/lib/rent-phases.ts: SIMD-0437 phase configuration

License

MIT