The moment you open Zelcore and your Ethereum balance refreshes, a remote server already knows three things: your IP address, every address in your wallet, and the exact timestamp of that lookup. That server is your RPC endpoint — the node your wallet talks to instead of running one itself. Most users never change it. Power users understand that choosing who sits at that connection point is one of the most consequential infrastructure decisions in self-custody.
This guide walks through why the default RPC matters, which EVM chains in Zelcore let you swap it out, how to evaluate and configure alternative providers, and what self-hosting looks like if you want to eliminate the middleman entirely.
Before You Start
This is an advanced configuration. You should already be comfortable with the basics of self-custody and understand what a node does at a conceptual level — if not, read Blockchain Nodes and Decentralisation first. You should also have Zelcore installed and set up with at least one EVM wallet. If you paired a hardware wallet with Zelcore, the custom RPC setting applies equally to hardware-backed accounts — your keys stay on the device regardless of which RPC you use (see Pairing a Hardware Wallet with Zelcore for the pairing flow).
Make note of your current working RPC before changing anything. If a new endpoint is unreachable, you'll want to revert without guessing.
What the Default RPC Sees
When Zelcore uses a third-party node as your default, that provider's infrastructure logs:
- Your IP address — correlated to every request you make.
- Every address you query — balance checks, token lookups, NFT fetches. If you have 12 addresses in one wallet, a single refresh sends all 12.
- Every transaction you broadcast — including the exact second it left your device, before it ever hits the mempool publicly.
- Token contract calls — revealing which DeFi protocols, swaps, or dApps you interact with.
In aggregate, this is a detailed behavioural and financial profile. For most users this is an acceptable trade-off. For users in adversarial environments, under sanctions scrutiny, running a business that competitors could monitor, or simply prioritising financial privacy, it is not.
The 2022 Infura and Alchemy episode made this concrete: both providers restricted wallet access in OFAC-sanctioned jurisdictions — Venezuela, Iran, and others — at the RPC layer. Users saw failed transactions and inaccessible balances with no recourse, because their wallet was routed through a single provider subject to US compliance obligations. RPC-layer censorship is not theoretical. It happened.
Which Chains Support Custom RPC in Zelcore
Zelcore exposes a custom RPC or custom node setting for EVM-compatible chains — Ethereum and the EVM networks it supports. To change the endpoint, locate the Custom RPC or Custom Node option in the coin's network configuration screen. Because Zelcore updates its UI regularly, consult the current in-app help or settings panel for the exact menu path rather than relying on any third-party screenshot.
UTXO chains — Bitcoin, Litecoin, Dogecoin, and roughly 31 UTXO networks in total — route through Zelcore-operated Blockbook and Insight infrastructure and are not user-configurable at the RPC level. If UTXO-layer privacy is your concern, that requires a different strategy (dedicated chain-layer tools, running your own Blockbook, or a different wallet architecture).
Solana RPC configurability in Zelcore is unconfirmed at time of writing. Check the current in-app settings to see whether a custom RPC option is exposed for your Solana account.
Choosing a Provider
Evaluate any RPC endpoint on five axes before trusting it with your traffic.
| Axis | What to look for |
|---|---|
| Privacy policy | Does the provider log IPs and addresses? For how long? Is data sold or shared? |
| Jurisdiction | Where is the company incorporated? OFAC, GDPR, and local data-retention laws vary. No provider is permanently immune — jurisdictions change. |
| Rate limits | Free tiers differ significantly. Sustained wallet use can hit limits on busy days. |
| Archive access | Archive nodes store all historical state. Required for querying old balances or replaying transactions. Most free tiers are full-node only. |
| Censorship track record | Has the provider restricted access before? Under what circumstances? |
The major free-tier offerings at time of writing:
- Infura — 3 M credits/day, 500 credits/sec. Operated by ConsenSys (US). Restricted access in sanctioned jurisdictions in 2022.
- Alchemy — 30 M compute units/month, 25 RPS. US-incorporated.
- QuickNode — 10 M credits/month, 15 RPS. US-incorporated.
- Ankr Node API — 30 RPS on the free tier. Operates nodes across multiple cloud providers and regions.
- Chainstack Developer — 3 M request-units/month, 25 RPS.
- LlamaRPC — community-run, typically unmetered on the free tier, though this is not guaranteed and may change.
chainlist.org is the standard directory for discovering RPC endpoints by chain ID. It lists community-contributed endpoints with chain metadata, so you can find the correct network URL and chain ID for any EVM network before entering it in Zelcore.
No provider earns a permanent clean bill of health on censorship. Jurisdiction is the determinative variable, and jurisdictions change. Evaluate based on current facts and revisit periodically.
Configuring a Custom RPC in Zelcore
- Open Zelcore and navigate to the EVM coin you want to reconfigure (e.g. Ethereum).
- Open that coin's settings or network configuration. Look for a Custom RPC, Custom Node, or network override option.
- Enter the HTTPS endpoint URL for your chosen provider. If the provider requires an API key, it is typically embedded in the URL (e.g.
https://mainnet.infura.io/v3/YOUR_KEY) — keep that key private. - Enter the chain ID for the network. For Ethereum mainnet this is
1. Mismatched chain IDs will cause transaction signing failures. Verify the chain ID at chainlist.org. - Save and confirm the connection. Zelcore should show a successful node connection; your balance will refresh through the new endpoint.
- Test with a read operation first — check your balance — before broadcasting any transaction. This confirms the endpoint is live and returns correct data.
For additional context on how Zelcore keeps state consistent when you reconfigure infrastructure, see Syncing Zelcore Across Devices.
Self-Hosting: Running Your Own Node
The most privacy-preserving option is a node you operate yourself. Your wallet talks only to your own infrastructure, and no third party sees your addresses or IP.
Ethereum full node (pruned):
- Clients: Geth or Nethermind (execution) + Lighthouse, Prysm, or Teku (consensus)
- Storage: ~500 GB NVMe SSD for a pruned execution state + ~200 GB for the consensus client
- Hardware: 4+ cores, 16 GB RAM minimum
- Sync time: typically 12–48 hours depending on method and hardware
Erigon in full-pruning mode is closer to ~2 TB; archive mode is 2.5 TB+.
Cloud VPS: A capable VPS (4 vCPU, 16 GB RAM, 1 TB NVMe) typically costs $50–$100/month. You're trusting the cloud provider's infrastructure, but not an RPC intermediary.
Once your node's JSON-RPC port is open (default :8545 for Geth/Nethermind, protected behind a reverse proxy with TLS), enter your node's public URL in the Custom RPC field exactly as you would a third-party provider. Restrict the port to your wallet's IP if possible.
If Something Goes Wrong
Balance shows zero or fails to load. The endpoint is unreachable or returned an error. Verify the URL and chain ID are correct. Check whether the provider has an outage status page. Revert to the previous endpoint if needed.
Transactions fail to broadcast. Your custom RPC may be a read-only archive node, or the provider may be behind on sync. Some free-tier nodes disable eth_sendRawTransaction. Confirm the node type supports transaction submission.
Rate limit errors. You've exceeded the provider's free tier. Upgrade the plan, switch providers, or reduce how often your wallet refreshes.
Chain ID mismatch errors. Re-verify the chain ID at chainlist.org. Using testnet chain IDs on mainnet (or vice versa) will cause transaction signing to fail.
Node not synced. A self-hosted node that hasn't finished syncing will return stale balances. Wait for full sync before routing live wallet traffic through it.
Summary
The RPC endpoint your wallet uses is not neutral infrastructure — it is a surveillance and potential censorship surface operated by a company in a specific jurisdiction, subject to that jurisdiction's laws and compliance obligations. Zelcore gives EVM-chain users the option to replace the default with any endpoint they trust more: a privacy-forward provider, a geographically distributed node, or a machine they run themselves.
Choose your provider using the five-axis rubric above, verify the chain ID at chainlist.org, test with a read operation before your first transaction, and revisit your choice whenever the regulatory or operational picture for your current provider changes.
