What is a Delinquent Validator?
A validator is labeled delinquent when they fail to sign recent blocks. The benchmark is straightforward: if a validator hasn’t cast a single vote within the last 128 slots—which translates to roughly one minute of blockchain time—they fall into the delinquent category. When a validator is delinquent, the stake delegated to them stops earning rewards for that duration. However, your staked amount remains safe; it’s still held by the protocol.
To visualize this, think about delegating to a food truck operator. You give them capital. They take that money to buy food, park in a prime location, and run their business. Every day they sell meals, a slice of the profits goes into your account. One Monday, though, the truck never opens. Maybe the engine is busted, maybe they lost their keys, maybe the owner has the flu, it doesn’t really matter. Your investment is safe, the truck is still there, but there are zero sales going in. A delinquent validator is exactly this: a shuttered food truck. None of your money is being stolen, nothing is being lost, but no rewards are coming in.
How a Validator Becomes Delinquent & The Costs Involved
There are several ways a validator can become delinquent. Most of the time it’s just simple downtime. If an NVMe drive dies on a validator server that processes hundreds of gigabytes per day, that is a common occurrence. A network connection can go down. Or upgrades can fail. For example, an operator updates their node to a fresh build of Agave and it refuses to boot up, so that node goes offline for however long it takes that operator to solve the issue.
During the period of an upgrade, delinquency is normal, as the operator tries to upgrade as many nodes as possible. You can see a sharp spike in validators going delinquent every time an update goes out, as a result of operators being unable to finish their upgrades.
This adds up over time. Epochs on Solana are around two days long, and rewards are calculated and given out based on how many votes a validator signs during each Epoch. If a validator goes down for a single Epoch, all of the rewards earned during that period will go to zero. Suppose you delegated 500 SOL (roughly $40,000 at the price of $80), and your operator delivers an APY of 7%. That one missed Epoch costs you around $20 (0.1 SOL, to be exact), which is not too bad. If you ignore your validator account entirely for a quarter of the year, that can add up, and keep in mind that the delegation needs to happen at Epoch boundaries, so if you decide to redelegate on a Saturday, you have to wait two more days for the epoch to finish.
One major factor that differentiates Solana from what the Ethereum stakers experience is that no slashing happens on Solana today. When your delegated funds stop generating returns, it’s because of the delinquency of the validator. Nothing else. Slashing refers to validators having to “burn” some of their staked SOL in order to be penalized for bad actions. There are several proposals out to introduce this in Solana (one of the most famous ones is SIMD-0204). However, all of these proposals focus only on malicious acts like a validator signing two different blocks at once and never delinquency.
Delinquency vs Ethereum Downtime
An offline validator on Ethereum gets slashed. By failing to provide their attestation during an Ethereum validator round, they are subject to “inactivity penalty”, which roughly equals the rewards they would’ve got, so their balance slowly starts to decrease day by day and, if there are a large number of validators being offline simultaneously, even bigger “inactivity leak” is applied. Ethereum stakers are in a way forced to ensure they never miss a day of uptime, whereas Solana validators are simply left not paid for that day.
Obviously, this comes at a cost to the Solana community. Solana delegators don’t risk having their stake slashed, which makes it far safer to choose a “good enough” validator and not necessarily a top-tier one. However, it also means that a “good enough” or poorly-managing operator can get delegations without facing any penalties for doing a poor job in terms of uptime. This is one of the major flaws of the current Solana staking system, and this is one of the main reasons slashing mechanisms are proposed and developed.
Why You Should Care
You can fully control your delinquency risk with the click of a couple of buttons, once you have the knowledge. If you check your Phantom account after you haven’t touched the crypto space for a couple of weeks, and you notice that your validator hasn’t given you any rewards for the last 12 days, this should be a red flag. A quick search on Solana Compass, for example, tells you that your validator has been delinquent since the 5th of May, when they upgraded to a faulty version of Agave v.4.0 and never got around to fixing it. In twelve days, at a 7% APY on your 500 SOL, you’ve quietly lost around a SOL worth $80. Not the end of the world, but a waste of money nonetheless. You just redelegate, wait until the Epoch boundary, and the cycle continues.
This is one of the problems that liquid staking attempts to solve. Marinade and Jito, for example, maintain their own validator pool of validators, which they keep on checking for delinquency and uptime. Whenever one of these validators goes down or doesn’t deliver as promised, they take your stake away from them. That’s why if you choose to stake with Marinade or Jito, your mSOL and JitoSOL tokens are never at risk of becoming delinquent: because they don’t allow it.
You do of course get full control over who you choose to delegate to if you go this route, with full control comes full responsibility, so if you choose solo stake you need to watch the validator.
Can a delinquent validator steal my staked SOL?
No, a delinquent validator cannot steal your staked SOL. Since you can’t actually send any delegated funds to a validator (they stay in your own stake account), there is no way for the validator to steal anything from you. It is only the rewards that stop flowing in when a validator is delinquent.
