How Endur Chooses Its Validators?
TL;DR
Validators run the show in any proof-of-stake network. They are the bridge between protocol rules and actual execution: validating blocks, signing attestations, and distributing rewards back to delegators. When they perform, the flywheel spins. Stakers earn rewards, re-stake them, compounding yield grows, and more capital flows in. When they miss, the flywheel stalls.
On Starknet, this dynamic is sharper than most chains. A missed attestation does not reduce your rewards proportionally. It eliminates them entirely for that epoch. Endur runs a curated three-validator architecture to keep that flywheel turning every single epoch.
Key takeaways:
Validators are the operational backbone of any staking ecosystem, converting protocol incentives into real yield for delegators
The validator-delegator-reward loop creates a compounding flywheel: better performance attracts more stake, which strengthens security, which sustains rewards
Starknet's all-or-nothing attestation model means validator quality has a direct, measurable impact on your APY
Endur operates three active validators , distributing stake across independent operators to minimize single points of failure
Endur's backend auto-claims and re-stakes rewards every epoch, so xSTRK and xyBTC compound without any action from you
I. Validators Run the Show
Every proof-of-stake network runs on a simple loop: protocols define rules, validators execute them, and rewards flow to validators and their delegators. Those rewards get re-staked, increasing security, attracting more capital, and compounding the system. This staking flywheel only works if validators consistently perform.
Validators are the bridge between protocol design and real yield. You can have perfect tokenomics and reward schedules, but if validators miss attestations or go offline, rewards don’t materialize. The protocol allocates rewards and validators are the ones who actually earn them.
This is why networks like Ethereum and Solana place heavy emphasis on validator performance, whether through curated sets like Lido Finance or permissionless models like Rocket Pool. Across all designs, one truth holds: validator quality determines yield.
On Starknet, this is even more critical. Its Phase 2 staking introduces epoch-based attestations with an all-or-nothing reward model. Miss an attestation window, and both validators and delegators earn nothing for that epoch, no partial rewards, no recovery.
For stakers and especially for Endur, validator selection isn’t just important. It directly determines whether the reward flywheel compounds or breaks.
II. How Starknet Staking Works Under the Hood
To understand why validators matter, it helps to understand exactly how Starknet staking works.
Epochs and Attestations
Starknet organises time into epochs. Within each epoch, each active validator is assigned a set of randomly selected blocks to attest. Attestation means signing off on a block to confirm its validity, a lightweight but time-sensitive operation.
The key constraint: the attestation must be submitted within a defined block window. Miss the window, and that epoch's rewards for all delegators to that validator are forfeit. The model is deliberately strict. It is designed to identify reliable validators before they take on heavier responsibilities in future staking phases.
The Minting Curve
Starknet's total staking rewards are governed by a minting curve defined by this formula.
M = C/10 x sqrt(S)
Here, S is the staking rate as a percentage of total supply and C is the maximum inflation constant. The community voted with 98.94% approval to set C at 1.6%, making it one of the most conservative inflation models across any major L2.
At the current staking rate of roughly 23% of circulating STRK, this translates to an approximate 7% annual return for stakers. But that yield is meaningful precisely because it is scarce. There is no generous inflation buffer to absorb validator underperformance. Every missed epoch is felt.
How Rewards Flow to xSTRK
When you stake STRK through Endur, you receive xSTRK, behind the scenes, Endur's backend claims rewards and re-stakes them automatically every epoch. This is what makes xSTRK appreciate in value relative to STRK over time: each epoch's rewards are folded back into the pool, increasing the xSTRK exchange rate.
The same mechanism applies to BTC liquid staking variants (xWBTC, xtBTC, xLBTC, xsBTC).
If a validator misses attestations, those rewards are never claimed. The xSTRK exchange rate grows more slowly than it should. The impact is direct and compounding.
III. Endur's Three Active Validators
Endur routes capital to a curated set of three active validators rather than delegating broadly across the entire Starknet validator set. Each operator was selected for infrastructure quality, operational track record, and alignment with Endur's reliability standards.
Karnot (Largest Stake Allocation)
Karnot is the largest validator in Endur's delegation set by total stake. As the infrastructure partner behind Endur since launch, Karnot brings deep Starknet-native expertise, having built app-chain solutions for projects like Kakarot and Pragma. Karnot's validator runs with redundant infrastructure, automated failover, and 24/7 monitoring. It initially launched with a 0% commission rate to bootstrap Starknet's validator ecosystem and remains one of the most consistently performant operators on the network.
Twinstake (Institutional Infrastructure)
Twinstake operates as a regulated digital asset staking provider, bringing institutional-grade operational standards to Endur's validator set. This is the same infrastructure that powers Endur's institutional BTC staking pipeline, with compliance workflows, validator-level SLAs, and enterprise monitoring. Twinstake's inclusion ensures Endur meets the reliability bar required by institutional capital allocators deploying BTC into Starknet's consensus layer.
Unwrap Labs (Endur's Own Validator)
Unwrap Labs is Endur's in-house validator, operated by the core team behind the protocol. Running a first-party validator gives Endur direct operational visibility into network conditions, epoch timing, and attestation performance. It also ensures the protocol always has at least one operator it fully controls, providing a baseline for performance benchmarking against third-party validators.
Why Three Operators?
Distributing stake across three independent validators with distinct infrastructure setups protects against correlated failures. If Karnot's infrastructure experiences an issue in a given epoch, only the portion of stake delegated to Karnot is affected. Twinstake and Unwrap Labs continue earning. The reverse is equally true. This multi-validator architecture is fundamental to the consistency of xSTRK and xyBTC yield.
IV. What Endur Looks for in a Validator
Beyond its current three operators, Endur evaluates validators against four criteria before adding them to the delegation set.
1. Uptime and Attestation Rate
The most important metric. Starknet's Foundation Delegation Program and StarkWare's own delegation program both require 99% minimum liveness from participating validators. Endur holds its operators to the same standard. A validator with consistent near-perfect attestation records earns a position in the delegation set. A validator that misses regularly does not.
This is not just about the current snapshot. Endur evaluates historical performance over time to distinguish validators that had a brief operational issue from those with structural reliability problems.
2. Commission Rate and Fee Policy
Validator commission is the percentage of staking rewards retained by the validator before passing the rest to delegators. A validator charging 20% commission gives you 80 cents of every dollar earned. A validator charging 5% gives you 95 cents.
Endur targets validators with competitive commission structures that balance sustainable validator economics with strong returns for stakers. Extremely low commission can signal a validator operating at a loss, which introduces its own longevity risk.
3. Operational Standards
Professional validators run infrastructure with redundancy built in. Backup nodes, failover systems, alerting, 24/7 monitoring. Consumer-grade setups on a home server might post good numbers for months, then go dark overnight when something breaks.
Endur prioritises validators with demonstrable institutional or professional operational standards. All three of its current validators (Karnot, Twinstake, Unwrap Labs) run dedicated infrastructure with automated monitoring and incident response procedures.
4. Validator Concentration Risk
Distributing stake across multiple validators rather than concentrating it in one or two protects the protocol from single points of failure. This diversification also supports Starknet's decentralisation goals. A healthy, distributed validator set is better for the network's long-term security, and by extension, for the value of STRK itself.
Open Delegation vs. Curated Delegation
There are two broad approaches to validator selection in liquid staking.
Open delegation allows any validator to participate and receive stake. The stake is distributed algorithmically, often weighted by the size of the validator's existing stake. Rocket Pool on Ethereum is the clearest example: over 3,000 permissionless node operators, maximizing decentralisation but introducing variance in operator quality.
Curated delegation restricts the validator set to operators that meet defined criteria. Lido on Ethereum operates this way, with its Node Operator Sub Governance group (LNOSG) managing a permissioned set of roughly 30 professional operators. The protocol actively manages which validators receive stake and adjusts allocations based on ongoing performance.
Endur uses curated delegation for both STRK and BTC liquid staking. Capital is routed exclusively to its three vetted operators: Karnot, Twinstake, and Unwrap Labs. The validator set is reviewed and updated as performance data evolves, with the flexibility to add new operators like Threshold Network's validators, which were recently integrated to support tBTC staking flows.
The tradeoff is real. A curated set is less permissionless than an open one. But for holders who want consistent, reliable yield from their xSTRK and xyBTC, the reliability of curated infrastructure is the point.
VI. How This Shows Up in Your Returns
The difference between a validator with 99% attestation rate and one with 85% attestation rate is not 14% of your rewards. Because of the all-or-nothing epoch structure, a validator missing 15% of epochs loses 100% of rewards for those epochs, not a proportional share.
Over a year, the compounding effect of this difference is significant. Endur's auto-compounding mechanism means every epoch's rewards are re-staked. A missed epoch is not just a lost reward, it is also a smaller base for future compounding.
At scale, the aggregate difference between a 95th percentile validator set and an average one translates into meaningfully higher returns distributed to stakers. This is why Endur's curated approach with three high-performance operators exists: to capture as close to 100% of available epoch rewards as the infrastructure allows.
Frequently Asked Questions
Can I see which validators Endur delegates to?
Yes. You can view all active validators, their commission rates, and their attestation performance on the Endur dashboard and on Voyager, Starknet's block explorer. Endur currently delegates to Karnot, Twinstake, and Unwrap Labs.
What happens if one of Endur's validators goes offline?
Endur distributes stake across three independent validators. If one goes offline, only the portion of stake delegated to that validator is affected for that epoch. The rest continues earning normally. Endur's backend monitors validator performance and can rebalance delegation in response to sustained underperformance.
Does Endur charge a fee for managing validator delegation?
Endur charges a 15% commission on staking rewards. This covers protocol operations, validator management, backend infrastructure, and ongoing security. Endur charges 0% on deposits and withdrawals.
Why do rewards auto-compound in xSTRK rather than being paid out separately?
Auto-compounding means your rewards immediately begin earning their own rewards. This is more capital-efficient than receiving separate reward payments and having to manually re-stake. The xSTRK exchange rate increases over time as rewards accumulate, so the longer you hold xSTRK, the more STRK each token is worth.
How is this different from delegating directly to a validator?
Direct delegation ties you to a single validator's performance and locks your STRK for 21 days when unstaking. Endur distributes stake across three curated validators, auto-compounds rewards every epoch, and gives you liquid STRK and BTC that can be deployed across DeFi protocols without unstaking.
