XPHERE Union
The XPHERE Union is the network's core validator group. Union members validate the blocks produced on the Proof Chain, record them on the Main Chain, take part in governance, and receive a protocol-defined share of block rewards and transaction fees.
Union membership is permissioned: each membership slot requires a 35,000,000 XP stake and is admitted through the Foundation after evaluation. Applications go to Contact@X-phere.com.
What the Union Does
| Role | What it means |
|---|---|
| ① Block validation | Validating the blocks produced on the Proof Chain and finalizing them on the Main Chain through PBFT consensus. Members take turns proposing. |
| ② Governance participation | Voting on network policy — one vote per member, not per slot, with the Foundation breaking ties. See Governance. |
| ③ Reward distribution | Union members collectively receive 40% of each minted block reward and 20% of transaction fees. See Tokenomics. |
The Union in the Dual-Chain Architecture
XPHERE separates the two jobs a Layer 1 has to do — deciding who may write a block, and agreeing on what the block contains — across two chains:
| Chain | Consensus | What it decides |
|---|---|---|
| Proof Chain | PoW (xpHash) | Validator selection |
| Main Chain | PBFT | Block consensus |
Within the Union, proposer turns rotate round-robin — eligible slots are cycled in a predetermined, sequential order rather than competing for a turn. Proof Chain mining works the other way: miners compete through xpHash Proof-of-Work. See Mining Rewards and Union Staking for how the two interact.
A Union member may hold more than one slot, and each slot takes its own turn in the rotation. See Members for the current slot distribution.
What a Union Member Earns
Union members are paid from two separate sources: newly minted block rewards, and the transaction fees paid by users.
Block Rewards (minted)
A fixed amount of XP is minted every 60 blocks (≈ 60 seconds) and split three ways:
| Recipient | Share |
|---|---|
| Union | 40% |
| Miner | 40% |
| Foundation | 20% |
The Union share of a block goes to the member whose registered node address holds the proposer turn for that block. Current emission figures and worked examples are on Mining Rewards.
Transaction Fees
Transaction fees are not entirely burned. They are split four ways:
| Recipient | Share |
|---|---|
| Burn | 50% |
| Union | 20% |
| Miner | 20% |
| Foundation | 10% |
The 50% burn is the figure most often quoted outside the docs, but it is only half of the fee. The other 50% of every transaction fee is distributed — 20% to the Union, 20% to the miner, and 10% to the Foundation. A Union member therefore earns from network usage as well as from block issuance. The full four-way split is documented in Tokenomics.
Membership Requirements
| Requirement | Detail |
|---|---|
| Stake | 35,000,000 XP per membership slot |
| Infrastructure | Maintain stable server infrastructure |
| Policy | A commitment to contribute to network policy |
| Operations | The capability to administer and maintain the server on an ongoing basis |
Published Eligibility Floor
| Component | Published minimum |
|---|---|
| CPU | 16 cores or more |
| RAM | 32 GB or more |
The eligibility floor is what the Foundation publishes for applicants; provisioning must follow Validator Node, which reflects current chain size. Storage and network are therefore not listed above — those two figures move with the chain, and the Validator Node page is authoritative for both.
Block data alone already exceeds 300 GB and grows continuously. The operating requirement is 2 TB NVMe minimum, 4 TB NVMe recommended — see Validator Node for the full sizing table.
Meeting the eligibility floor makes an application admissible; it does not make a node operable. Full operational requirements for running a Main Chain validator — sizing, monitoring, and the operating conditions the Foundation enforces — are documented on Validator Node. Read that page before provisioning.
Registration Process
Registration runs in five steps:
| Step | What happens |
|---|---|
| 1. Apply | Submit an application and stake an initial 1,000,000 XP. |
| 2. Evaluation | The application is evaluated by the Foundation and existing Union members. |
| 3. Complete the stake | Stake an additional 34,000,000 XP, bringing the total to 35,000,000 XP. Registration is complete at this point. |
| 4. Technical support | The XPHERE Foundation provides initial technical support for bringing the node online. |
| 5. Ongoing operation | The member takes on the obligation to operate the node stably as part of the network. |
Step 5 is an ongoing obligation, not a formality. Union membership is a commitment to keep validating — the operating conditions are set out on Validator Node.
Governance
| Rule | Detail |
|---|---|
| Voting weight | One vote per member |
| Tie-break | Where a vote is tied, the XPHERE Foundation casts the tie-breaking vote |
Voting weight is per member, not per slot — holding multiple slots increases proposer turns and reward share, not voting power. The Foundation has not yet published a wider governance framework, so the two rules above are the full published set. Governance is where it will appear once published.
Current State
Read from on-chain data on 2026-08-05:
| Metric | Value |
|---|---|
| Active Union slots | 25 of a target of 31 |
| Stake per slot | Exactly 35,000,000 XP, identical across every slot |
| Total staked | 875,000,000 XP |
The member list, slot counts, and registration dates are on Members, along with three independent ways to verify them yourself:
| Source | Where |
|---|---|
| Tamsa Explorer | https://xp.tamsa.io/main/unions |
| XPScan | https://xpscan.io/unions |
| Public API | https://api.tamsa.io/api/v1/unions?page=1&count=100 |
curl "https://api.tamsa.io/api/v1/unions?page=1&count=100"
Slot counts and total stake change as slots are added. Treat the figures above as a snapshot and re-check one of the sources before citing them.
How to Apply
Send an enquiry to Contact@X-phere.com. Include the infrastructure you intend to operate and how you meet the requirements above; the Foundation and existing members evaluate applications at step 2 of the process.
Union membership is aimed at institutions and infrastructure partners. XP holders who want exposure to the Union reward share without operating a node can use the Foundation's non-custodial XP Union Vault at stake.x-phere.com — no node and no membership stake required.
See Also
- Members — the current member list and how to verify it on-chain
- Validator Node — authoritative hardware sizing and operational requirements for validators
- System Requirements — hardware sizing for Endpoint Nodes (XEN)
- Mining Rewards — emission schedule and the 20 / 40 / 40 minted-reward split
- Union Staking — the protocol-level Union reward share
- Tokenomics — supply, emission, and the fee burn