Open Source Blockchain Platforms: Public, Private and Permissioned

Picking a blockchain platform starts with one question: who is allowed to read the ledger, write to it and validate it? The answer splits the field into public, private and permissioned networks, and it narrows the list of open source platforms worth considering.

This guide covers both halves. First the network models and the trade-offs between them, then the main open source platforms and what each one is suited for.

Public, private and permissioned networks

Every blockchain client runs the same basic loop: receive transactions, agree on their order with other nodes, and append them to a shared ledger. What changes between network types is the access control around that loop.

Public (permissionless) networks

Anyone can run a node, submit transactions and take part in consensus. Bitcoin and Ethereum are the obvious examples. Validators are kept honest by economics: proof of work on Bitcoin, proof of stake on Ethereum since the 2022 Merge.

Public networks suit applications where no single party should be in control, where users hold their own assets, or where you want anyone to be able to verify the record. The costs are transaction fees, public visibility of every transaction, and throughput limits that push many applications onto layer 2 rollups.

Private networks

A single organization runs every node and decides who can connect. This is close to a replicated database with an append-only, tamper-evident log. It is useful for testing and for internal audit trails, but if one party controls all the validators, the main benefit of a blockchain (no single point of trust) is gone. Ask whether a conventional database with signed audit logs would do the same job more simply.

Permissioned (consortium) networks

Several known organizations each run nodes, and an access control layer built into the client decides who may join, who may transact and who may validate blocks. Validators are identified, so consensus can use fast, voting-based algorithms such as Raft, IBFT 2.0 or QBFT instead of mining or staking.

Permissioned networks fit cases where a group of companies needs a shared record that none of them controls outright: trade finance, supply chain tracking, interbank settlement, or the insurance workflows covered in blockchain for insurance and customer data.

Why choose permissioned

Compared with a public chain, a permissioned network offers:

• Clear governance. Members agree up front on who validates, how upgrades happen and how disputes are settled.
• Privacy. Transaction data is visible only to members, and most platforms add finer controls such as private channels or private transactions.
• Predictable cost and performance. There are no gas markets, and known validators allow quick finality.

Compared with a central database run by one party, it offers a record that every member can verify independently, with no member able to rewrite history alone.

The trade-off is that trust now rests on the consortium. If the members collude, or the network shrinks to one active operator, the guarantees weaken. Many consortium projects have stalled on governance and funding rather than technology, so plan the business arrangement as carefully as the architecture.

Quick comparison

Model	Who validates	Data visibility	Typical fit
Public	Anyone (stake or work)	Everyone	Open finance, tokens, user-held assets
Permissioned	Approved members	Members, by policy	Multi-company workflows, shared records
Private	One organization	That organization	Testing, internal tamper-evident logging

Open source platforms worth knowing

The list below favors platforms that are actively maintained as of 2026. Each is open source, but they differ in maturity, governance and the kind of network they target.

Ethereum clients (public)

Ethereum is the most widely used smart contract platform, and its clients are open source: execution clients such as Geth, Nethermind, Besu, Erigon and Reth, paired with consensus clients such as Lighthouse, Prysm, Teku and Nimbus. Smart contracts are usually written in Solidity and run on the Ethereum Virtual Machine (EVM).

Suited for: tokens, DeFi, NFTs and any application that benefits from a large public network and a mature tool chain. The same EVM runs on many layer 2 networks and sidechains, so code and skills carry across. Our Ethereum and Solidity getting started guide is a practical entry point.

Hyperledger Besu (public and permissioned)

Besu is a Java Ethereum client that runs on Ethereum mainnet and also supports private, permissioned networks with QBFT or IBFT 2.0 consensus, node and account permissioning, and private transactions. It is hosted by LF Decentralized Trust, the Linux Foundation body that took over the Hyperledger projects in 2024.

Suited for: enterprises that want EVM compatibility and Solidity tooling inside a consortium, with an option to connect to public Ethereum later. ConsenSys has wound down its older GoQuorum client and points enterprise users to Besu.

Hyperledger Fabric (permissioned)

Fabric is a modular permissioned platform, also under LF Decentralized Trust. It uses a membership service built on certificates, channels and private data collections to keep data between subsets of members, and pluggable ordering (Raft in production setups). Smart contracts, called chaincode, are written in Go, Java or JavaScript/TypeScript rather than a blockchain-specific language.

Suited for: consortium networks with strict privacy needs and complex membership, where teams prefer general-purpose languages. It has no native cryptocurrency.

Corda (permissioned)

Corda, from R3, is a distributed ledger rather than a classic blockchain: transactions are shared only with the parties involved instead of being broadcast to every node. An open source edition exists alongside R3’s commercial releases, and it is used mostly in regulated finance.

Suited for: bilateral or multi-party financial agreements where data should reach only the parties to a deal.

MultiChain (private and permissioned)

MultiChain is a fork of Bitcoin Core that adds permissions, native multi-asset issuance and data streams for storing and indexing records. It is open source under the GPL, with a commercial edition from its developer, Coin Sciences.

Suited for: permissioned asset tracking and tamper-evident record keeping when you do not need full smart contracts.

Cosmos SDK and Polkadot SDK (build your own chain)

Some teams need an application-specific chain rather than contracts on an existing one. The Cosmos SDK (Go, with CometBFT consensus) and the Polkadot SDK (Rust, formerly Substrate) are open source frameworks for building such chains, public or permissioned. Cosmos chains connect to each other through IBC; Polkadot chains can share security with the Polkadot relay chain.

Suited for: projects with custom fee models, governance or performance needs that a general-purpose chain cannot meet. They demand more engineering and operations than deploying a contract.

Bitcoin Core (public)

Bitcoin Core is the reference open source implementation of Bitcoin. Its scripting is deliberately limited, so it is not a general application platform, but it remains the most widely held and longest running public ledger.

Suited for: payments, settlement and applications that only need to anchor proofs (for example, timestamps or document hashes) to a highly secure chain.

Platforms from earlier lists that have moved on

The first version of this post, written in 2016, listed Eris, HydraChain, Openchain and Ethereum. Only Ethereum is still a sensible choice:

• Eris became Monax. Its EVM client was donated to Hyperledger as Burrow, which has since been retired.
• HydraChain, a permissioned extension of Ethereum, has not been maintained for years.
• Openchain is no longer developed.

The same is true of many early decentralized apps from that period, such as GitHub bounty, energy trading and smart-lock projects built on Bitcoin and Ethereum. Most have closed, pivoted or been acquired. The lasting lesson is to check a project’s release history and maintainers before building on it; a platform with no releases for two years is a liability, however good its feature list looks.

How to choose

Work through these questions in order:

1. Do several parties need a shared record that none of them controls? If not, a regular database is probably the better tool.
2. Must anyone be able to join or verify? If yes, use a public chain or a layer 2 on one. If participants are known, a permissioned network is simpler.
3. Do you need general smart contracts? EVM platforms (Ethereum, Besu) have the largest tool chain and talent pool. Fabric suits teams that prefer Go or Java. MultiChain covers asset and record tracking without contracts.
4. Who operates the network long term? Name the organizations that will run nodes and pay for them before writing code.

For a hands-on start, see how to set up a local private Ethereum testnet. For broader patterns in how teams use these platforms, read blockchain innovation patterns. If you are weighing platforms for a production system, Lightrains offers blockchain development services.

This article originally appeared on lightrains.com