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The official Solana Explorer: open source, forkable, the reference decoder

Solana's official Explorer is open source. Anchor IDL decoding, full CPI trees, cluster switching, self-hostable — the canonical reference UI.

The Solana Explorer at explorer.solana.com is the most-used Solana tool that almost nobody talks about. It's the canonical decoded view of any address, transaction, block, or slot on Solana — and unlike most production explorers in crypto, the entire thing is open source, sitting at github.com/solana-foundation/explorer.

Apache-2.0 licensed, Next.js, maintained by the Solana Foundation. You can run it locally, point it at devnet or a private cluster, and you get the exact same UI you see on the production site, decoding the exact same way.

What it does that the alternatives don't

Other Solana explorers — Solscan, SolanaFM, Solana Beach, XRAY — are excellent products. They do things the official Explorer doesn't: better analytics, better token portfolios, better wallet history. The official Explorer's niche is raw protocol fidelity:

  • Anchor IDL decoding as the reference implementation. When Anchor adds support for a new account or instruction type, the Explorer is where it lands first and where the canonical decoding logic lives.
  • CPI trees as they actually executed — every cross-program invocation, every compute unit consumed at each depth, every log emitted. Indispensable when debugging why your transaction failed in a way logs alone don't explain.
  • Sysvar values and built-in program decoding — the Explorer knows about every native program (System, Stake, Vote, Compute Budget, BPF Loader) and decodes their instructions natively without needing an IDL.
  • Cluster switcher for mainnet-beta, testnet, devnet, or a custom RPC URL. Inspect a devnet transaction with the same UI you use for mainnet.

Self-hosting against your own RPC

The least-known superpower: you can run the Explorer locally and point it at any RPC endpoint. Useful when you're working against a private devnet, a local solana-test-validator, a forked mainnet via Surfpool, or your own dedicated RPC node.

sh
git clone https://github.com/solana-foundation/explorer.git
cd explorer
npm install
npm run dev

# Open http://localhost:3000
# Then change the cluster URL in the top-right to your endpoint —
# e.g. http://localhost:8899 for a local test validator

Inside the dev loop, this beats every alternative. You get the full instruction decoding, CPI tree, and log inspection against transactions you just sent, with zero network round-trip to a third-party explorer.

Custom Anchor IDL decoding

The Explorer picks up Anchor IDLs in two ways:

1. From the program account. Anchor stores the IDL on-chain as a separate account associated with the program ID (the idl init command). The Explorer fetches it automatically and uses it to decode every instruction and account belonging to that program.

2. From a local file. When self-hosting, you can drop an IDL JSON into the codebase or supply it via the dev environment, and the Explorer will decode transactions against your unpublished program. Critical for debugging programs before you publish the IDL on-chain.

The decoding is the reference implementation — every other Anchor-aware tool (Helius, codama, custom indexers) effectively re-implements the logic the Explorer publishes here.

The forking pattern

Most branded Solana explorers and SVM-fork explorers are downstream of this repository. When a new Solana-based chain launches and needs a block explorer, the path of least resistance is forking the Foundation Explorer, swapping the default cluster URL, and rebranding the header. The decoders, the CPI tree rendering, the sysvar handling — all reusable.

That's why the visual language of so many Solana-adjacent explorers feels identical. It's not a coincidence; they share 90% of a codebase.

What it's not

The Explorer is intentionally not:

  • A wallet portfolio view. No PnL, no token-balance charts, no NFT galleries. Use Solscan or a wallet for that.
  • A network analytics dashboard. No TPS chart, no validator stake breakdown, no fee market history. The Explorer shows you what happened, not what trended.
  • A program metadata service. For upgrade authority, verification status, and IDL availability across many programs at once, see ProgramWatch.

The Foundation Explorer is the protocol-fidelity explorer. It tells you exactly what the validator saw, decoded through the canonical IDL machinery, and nothing else.

When to reach for it

  • Debugging a failed transaction. Paste the signature, see the full CPI tree with logs and CUs at each depth.
  • Inspecting an unknown program's instructions. If the program has an on-chain Anchor IDL, you get fully decoded instructions instead of base58 instruction data.
  • Local development. Self-host pointed at localhost:8899 and inspect every test transaction with full fidelity.
  • Verifying behaviour on devnet before mainnet. Cluster switcher makes the same UI work across networks.

Contributing

Open source. PRs welcome. If your program uses a non-Anchor instruction encoding the Explorer doesn't know about (Pinocchio with custom encoding, raw byte slices, a domain-specific format), adding a decoder to the Explorer is the single highest-leverage contribution you can make — every Solana developer benefits from it next time they paste a transaction signature.

References

It's the explorer everyone uses and nobody talks about. Bookmark the GitHub link too, not just the website — when you need to inspect a transaction against your own RPC or debug a program before it's public, the self-hosted path is the move.

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The official Solana Explorer: open source, forkable, the reference decoder | devrels.xyz