Migrate
A drop-in replacement for the Sim (Dune) API
Sim by Dune has announced it's winding down its balances, portfolio and activity API in mid-2026. NodeFlare picks up exactly those queries — native and ERC-20 balances and USD-valued portfolios for any address across all 23 EVM chains — plus the young chains Sim never covered. Migrate with a base-URL swap: free public endpoints, a free API key, or no-key x402 payments.
Heads up:Sim's hosted balances/portfolio/activity API is being retired (announced for mid-2026). Point your reads at NodeFlare before it goes dark — the public tier works today, no signup required.
Endpoint mapping
Every Sim surface has a NodeFlare equivalent.
| Sim (Dune) | NodeFlare | Returns |
|---|---|---|
| Token balances (native + ERC-20) | POST /data/balances | Balances for an address across every chain in one request. |
| Portfolio / net worth (USD) | POST /data/portfolio | USD-valued holdings with a rolled-up total, sorted by value. |
| Wallet activity / holdings report | POST /data/wallet-report | Per-chain native + token holdings and portfolio summary for an address. |
| Token metadata & safety | POST /data/token-safety | Symbol, decimals, contract check, ownership, risk score and signals. |
| Token approvals | POST /data/allowances | Which spenders a wallet approved, how much, and unlimited flags (revoke-risk). |
| Auto-discover a wallet's tokens | POST /data/portfolio/x402 (discover: true) | Scans Transfer logs to find every ERC-20 the address holds — no token list needed. |
All endpoints live under https://rpc.nodeflare.app. Append /x402 to a data endpoint for pay-per-call access with no account.
Migrate in one request
# Sim balances → NodeFlare /data/balances (free public tier)
curl -X POST https://rpc.nodeflare.app/data/balances \
-H 'Content-Type: application/json' \
-d '{
"address": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
"chains": ["eth", "base", "robinhood", "plasma"]
}'
# Sim activity/portfolio → NodeFlare /data/wallet-report
curl -X POST https://rpc.nodeflare.app/data/wallet-report \
-H 'Content-Type: application/json' \
-d '{ "address": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045" }'Why NodeFlare over the alternatives
Young chains Sim skipped
Own nodes for Robinhood Chain, Plasma, Ink, Zircuit, Soneium, BOB and Mode — coverage you gain by switching.
No-key x402 payments
Pay per call in USDC on Base, Polygon or Arbitrum — no account, no seat, no subscription. Built for agents.
Or pay by key
A free API key with a monthly compute allowance covers higher limits and heavy methods. No credit card to start.
Sim migration — FAQ
Is Sim (Dune) really shutting down its API?
Sim by Dune has announced it is winding down its hosted balances, portfolio and activity API in mid-2026, pointing developers to migrate. If your app reads wallet balances, portfolios or activity from Sim, you'll need a replacement before it goes dark. NodeFlare is built to be that drop-in.
How is NodeFlare a drop-in replacement?
The shapes line up. Sim's balances become NodeFlare's /data/balances, Sim's portfolio/net-worth becomes /data/portfolio (USD-valued with a total), and Sim's activity/holdings report becomes /data/wallet-report. It's one POST per query across all 23 chains instead of Sim's hosted endpoints — swap the base URL and the request body, keep your logic.
Which chains does NodeFlare cover that Sim didn't?
NodeFlare runs its own nodes for young chains Sim never indexed — Robinhood Chain (4663), Plasma, Ink, Zircuit, Soneium, BOB and Mode — alongside Ethereum, Base, BNB, Arbitrum, Optimism and Polygon. Migrating off Sim is a chance to gain coverage, not lose it.
Do I need an account or API key to migrate?
No. The public balances and portfolio endpoints are free and rate-limited per IP — start calling them today. For heavy methods, token discovery and higher limits, use a free NodeFlare API key or pay per call in USDC over x402 with no account at all.
How is pricing different from Sim?
Two options, both without a seat or a subscription. Pay-per-call in USDC over x402 (about $0.0003 per chain for balances) so you only pay for what you use, or a free API key with a monthly compute allowance. No minimum spend, no annual contract.
Move off Sim before the lights go out
The public balances and portfolio endpoints work right now — no signup. Wire them in today, add a free key or x402 when you need higher limits.