Solana Improvement Documents (SIMD) Guide

This Solana Improvement Documents (SIMD) Guide explains proposal categories, lifecycle terminology, landmark documents, token-economic implications, and where readers can track current status. Proposal numbers and status labels should always be checked against the linked repository before publication.

A Solana Improvement Document (SIMD) is a formal proposal for making changes to the Solana blockchain protocol. SIMDs provide a standardized, transparent process through which developers and validators can propose and ratify changes to Solana's network rules, client software, or ecosystem standards. They are publicly hosted on GitHub and follow a structured lifecycle from draft through review to final network activation.

Disclaimer: This article is for informational and educational purposes only. It does not constitute financial, investment, or legal advice. Cryptocurrency investments carry significant risk, including the risk of total loss. The governance proposals and economic parameters discussed here may change after publication. Always conduct your own research and consult a qualified financial advisor before making investment decisions.

Solana Improvement Documents (SIMD) Guide: Core Concepts

SIMDs cover every aspect of Solana's protocol and are organized into three categories based on the layer of the network they govern. Core SIMDs address consensus rules and protocol-level mechanics. Networking SIMDs cover the peer-to-peer layer through which validators communicate. Meta SIMDs govern the SIMD process itself, including standards and tooling.

The SIMD system exists because blockchain protocols require a transparent, community-auditable process for change. Before formal improvement documents, protocol changes on many networks happened through informal developer consensus, with limited visibility for token holders or validators. SIMDs replaced that opacity with a public process: every proposal is filed in the official SIMD GitHub repository, open to reading and commenting by anyone. This open-source development model keeps governance accessible to the entire Solana community.

What is a protocol? A protocol is the set of rules all computers on the Solana network must follow to agree on the shared state of the blockchain. Changing a protocol rule requires every participant to update accordingly, which is why governance processes like SIMDs exist.

The Solana Foundation (the non-profit organization that administers the SIMD repository) serves as editorial steward of the process. The Foundation assigns SIMD numbers, facilitates editorial review, and maintains the repository, but it does not hold unilateral authority to approve or reject proposals. Governance authority rests with the validator community through stake-weighted voting.

SIMDs directly affect anyone holding SOL (Solana's native token). Governance decisions made through SIMDs can change the inflation schedule that determines how many new SOL tokens are issued each year, the fee structures that govern how transaction revenue flows through the network, and the staking mechanics that determine how much SOL holders earn when they delegate to validators.

Why SIMDs Matter: Governance on the Solana Network

Blockchain governance is the process through which a decentralized network with no central authority makes decisions about changing its own rules. Unlike a company that can issue a software update unilaterally, a blockchain protocol requires consensus from a distributed set of participants. Governance frameworks like SIMDs exist to make that consensus process transparent and open to scrutiny. Solana uses a hybrid model: proposals are debated off-chain on GitHub and in community forums, while consensus is signaled through validator client upgrade adoption rather than through direct token-holder votes recorded on the blockchain. This is distinct from on-chain governance models used by some decentralized autonomous organizations (DAOs), where token holders vote directly on proposals via blockchain transactions.

Blockchain networks must evolve. Security improvements, performance upgrades, and economic parameter changes are all necessary over time. The challenge is that Solana (co-founded by Anatoly Yakovenko in 2017) is a decentralized, proof-of-stake Layer 1 blockchain with no single owner. Without a central authority, every change to Solana's rules requires that structured process. SIMDs are that process.

For SOL token holders, governance matters because the parameters that SIMDs govern directly affect token value and yield. SOL's inflation schedule (which determines annual token issuance), the fee structures routing priority fees to validators, and staking mechanics that set reward rates all fall under SIMD governance. A governance decision that reduces SOL's annual issuance rate changes the token's supply dynamics. A decision that routes more priority fees to validators changes the economics of staking.

Validators (the network participants who operate Solana node software to process transactions, produce blocks, and maintain consensus) are the primary governance actors. Solana uses proof-of-stake (PoS) consensus, meaning validators are selected to produce blocks in proportion to the amount of SOL staked to them. This same stake-weighting applies to governance: validators with more SOL delegated to them carry proportionally more voting weight, similar to how shareholders with larger holdings carry more votes in a company decision.

Solana's architecture also includes Proof of History, a cryptographic timekeeping innovation that allows the network to order transactions without requiring validators to communicate about time. This architectural distinctiveness is one reason Solana built its own improvement proposal system rather than adapting Ethereum's framework directly.

DeFi protocols built on Solana (such as Jupiter, Marinade, and Raydium) also have a stake in SIMD outcomes. Protocol changes governing compute budgets, account structures, or fee mechanics can directly affect how these applications operate, even though DeFi protocols do not hold direct voting rights in the SIMD process unless they also operate validator nodes.

Validators are central to protocol adoption because they choose which compatible software to run. SOL holders may influence the validator set through delegation, but delegation is not a direct vote on every SIMD. While validators may signal support or adopt compatible software, anyone can participate by following proposals on GitHub, submitting feedback in pull request comments, or advocating positions in the Solana Foundation forum and developer Discord.

The SIMD Lifecycle: From Proposal to Network Activation

Every SIMD follows a defined lifecycle that begins the moment a proposal is submitted to the official SIMD GitHub repository and ends when the change activates on Solana's mainnet or the proposal is formally closed.

The table below provides an at-a-glance reference for all eight lifecycle stages.

Stage 1: Draft

A SIMD enters the Draft stage when its author submits a pull request (a request to add the proposal file to the repository) to the SIMD GitHub repository. The proposal must follow a standard format including a preamble, abstract, motivation, specification, backwards compatibility analysis, drawbacks, and rationale. Community members review the draft in the pull request comments, and the author refines the proposal based on feedback. This stage can last weeks or months depending on complexity and community response.

Stage 2: Review

Once a draft reaches sufficient maturity, it enters formal Review. SIMD editors (Solana Foundation personnel who serve an editorial rather than governance role) assess the proposal for completeness, proper formatting, and adherence to the SIMD template. Editors may request revisions and evaluate format only, not the proposal's merit. This stage typically takes weeks.

Stage 3: Last Call

Last Call is a structured 14-day final comment period signaling that a proposal is approaching acceptance. Validators, developers, and other stakeholders can raise any remaining objections. If no significant objections emerge, the proposal advances to Accepted.

Stage 4: Accepted

An Accepted SIMD has cleared editorial review and the Last Call period. Acceptance means the proposal is formally recognized as ready for implementation. Client teams (Anza for the Agave client, Jump Trading for the Firedancer client) begin building the changes into upcoming validator software releases.

Stage 5: Activated

Activation is the governance moment that matters most. Validators signal their support by upgrading (or withhold support by declining to upgrade) their Agave or Firedancer client software to the version implementing the SIMD. Because Solana uses stake-weighted voting, a SIMD activates when enough SOL stake crosses the required threshold. The specific threshold is documented in the SIMD repository for each proposal type. Validator software upgrades implementing a SIMD typically take effect at the start of a new epoch (Solana's approximately 2-3 day cycle after which stake delegations and staking rewards are updated).

Stage 6: Final

A Final SIMD is fully implemented and live on Solana's mainnet. The change is permanent and the governance process for that proposal is complete.

Terminal States: Withdrawn, Rejected, and Stagnant

A SIMD may exit the process without reaching Final status. Withdrawn means the author voluntarily pulled the proposal. Rejected means the proposal failed to achieve the required stake-weighted validator support or was rejected at the editorial stage. Stagnant describes proposals with no activity for an extended period.

What happens if a SIMD is rejected? A rejected SIMD does not permanently close the door on the subject matter. Authors can revise the approach, address the objections that led to rejection, and resubmit a new SIMD on the same topic with updated reasoning or modified parameters.

The timeline from Draft to Final varies considerably. Some SIMDs move from submission to activation in weeks when community consensus forms quickly. Others, like SIMD-0123 (inflation schedule adjustment) and SIMD-0096 (validator fee distribution), generate substantial debate that extends the process over months.

How SIMDs Affect SOL Token Economics

Not all SIMDs affect SOL holders equally. Proposals that change internal technical standards often have no visible effect on token holders. The SIMDs that matter most to investors and stakers are those that modify Solana's inflation schedule or fee distribution rules, because these parameters directly affect token supply dynamics and staking yields.

Key Term: Inflation Schedule. Solana issues new SOL tokens according to a predetermined schedule that decreases over time. The starting annual issuance rate is defined by the protocol, and the schedule gradually reduces that rate each year toward a long-term floor. This schedule can be modified through the SIMD process. For current figures, see SOL market data on CoinGecko.

How SIMDs Affect SOL Staking Rewards

Solana's inflation schedule governs how many new SOL tokens are minted each year and distributed as staking rewards to validators and their delegators (SOL holders who delegate their tokens to a validator to earn a share of block rewards). When you stake SOL, your yield derives primarily from this inflationary issuance, not from transaction fees. The staking reward rate is a function of total SOL staked and the annual issuance rate.

A SIMD that reduces the inflation schedule directly affects staking yields. If the annual issuance rate decreases, validators and delegators receive fewer newly minted SOL tokens per epoch. The same reduction also means the overall supply grows more slowly, reducing dilution for holders who do not stake. Whether a lower inflation rate benefits any individual holder depends on their staking behavior and holding period.

Do SOL holders get a governance vote? SOL token holders do not have a direct formal vote in the SIMD process. Formal voting authority belongs to the validator set through stake-weighted client upgrade adoption, not through direct token-holder voting. This distinction matters for anyone evaluating Solana's governance relative to DAO-based systems. SIMD-0123, covered in the Landmark SIMDs section below, is the primary example of a SIMD that directly governs the inflation schedule.

How SIMDs Affect Validator Economics

Validators earn income from two sources: inflation-based staking rewards and priority fees paid by users to prioritize their transactions during high-demand periods. These income streams are governed independently, and SIMDs can affect each separately.

Solana's fee structure consists of a base fee (fixed by protocol) plus an optional priority fee that users add to move their transactions ahead during congestion. The way priority fees are distributed between validators and a protocol burn mechanism has been a recurring subject of SIMD governance. SIMD-0096, one of the most consequential governance decisions in Solana's history, directly addressed this distribution.

Changes to how priority fees flow to validators affect validator profitability, which in turn affects the commission rates validators charge delegators and the staking yields that SOL token holders earn. The tokenomics of SOL (the economic design governing token supply and distribution) are shaped by both the inflation schedule and the fee distribution rules. Both are subject to the SIMD process.

The Landmark SIMDs section below covers SIMD-0096 and SIMD-0123 in specific detail.

Landmark SIMDs: The Proposals That Shaped Solana

Four SIMDs have shaped Solana's validator incentives, network performance, fee economics, and token supply more than any others in the network's governance history. Reviewing them shows what the SIMD process looks like in practice.

Verify current status in the official SIMD GitHub repository as statuses change over time.

SIMD-0033: Timely Vote Credits

SIMD-0033, known as the timely vote credits proposal, reformed how the Solana network awards vote credits to validators, incentivizing faster and more accurate voting. Before this proposal, validators received the same vote credit reward regardless of how quickly they submitted their votes. The restructured credit system gives validators who vote promptly more credits than those who vote late, aligning validator incentives with network performance goals. This SIMD demonstrates that governance addresses nuanced validator incentive design, not only high-level token economics.

SIMD-0088: Partitioned Epoch Rewards

A performance bottleneck at epoch boundaries prompted SIMD-0088. Previously, staking rewards were distributed in a single block across the entire validator set at each epoch transition, creating a predictable spike in computational load. SIMD-0088 partitioned this distribution across multiple blocks within the transition period, eliminating the bottleneck. This is a clear example of SIMD governance addressing network performance and scalability rather than purely economic parameters.

SIMD-0096: Validator Fee Distribution Reform

The question of how priority fees should flow through the Solana network was the central subject of SIMD-0096. Before this proposal, a portion of priority fees paid by users was burned (destroyed) rather than distributed to validators. SIMD-0096 proposed that validators receive 100% of the priority fees on transactions they process. The debate was significant: proponents argued that routing all priority fees to validators strengthens the incentive to include high-fee transactions and improves network economics for node operators. Critics raised concerns about MEV (maximal extractable value) dynamics and long-term fee economics.

For validators, SIMD-0096 means a direct increase in fee income per block. For delegators (SOL holders who delegate to validators), the downstream effect depends on how validators pass through additional revenue in their commission structures. Exchanges listing SOL and operating Solana infrastructure may also need to implement technical changes introduced by activated SIMDs affecting fee mechanics. See the official SIMD-0096 proposal document for the full specification.

SIMD-0123: Adjusting Solana's Inflation Schedule

SIMD-0123 proposed adjusting Solana's inflation schedule, targeting a reduction in the annual rate at which new SOL tokens are issued to the network. The proposal addresses a concern that Solana's original inflation trajectory maintains a higher long-term issuance rate than may be necessary once the network matures and fee income grows as a proportion of validator revenue.

If fewer new SOL tokens are created each year, holders who do not stake their SOL experience slower dilution of their share of total supply. Stakers still earn a proportional share of newly issued tokens, but at a reduced absolute quantity. SIMD-0123 is distinct from fee-burning mechanisms (which reduce supply by destroying transaction fees) and from staking APY (a derived metric, not a directly governed parameter). This proposal governed the issuance schedule itself. See the official SIMD-0123 proposal document for the full specification, and verify current status at time of reading.

Is Solana's Governance Decentralized? An Honest Assessment

Solana's governance is partially decentralized by design, but whether that design achieves meaningful decentralization in practice depends on how you weigh open participation against concentrated voting power.

The case for meaningful decentralization: Proponents note several structural features that support decentralization. Anyone can submit a SIMD with no gatekeeping at the proposal stage, making the input layer open. All proposals are publicly visible and open to community comment, making the debate layer transparent. Validator votes are expressed through software upgrade adoption, which is publicly observable. The Solana Foundation cannot unilaterally implement changes; validator adoption is required for a SIMD to activate, meaning no single organization can force a protocol change.

The legitimate concerns: Critics argue that several structural features concentrate effective power. Validator stake is not evenly distributed: a relatively small number of large staking pools and institutional validators control a disproportionate share of total delegated SOL, meaning a handful of large operators can determine governance outcomes. The Solana Foundation's editorial role, while framed as administrative, gives it meaningful influence over which proposals receive formal review and progress through the lifecycle. Historically, Solana also relied heavily on a single primary validator client implementation, concentrating software development influence (though this is evolving as Firedancer gains adoption).

How to check: Solana's validator vote distribution and stake concentration data is publicly available at validators.app and the Solana Beach explorer. Reviewing the top-20 validators by stake shows the concentration of voting power in the current epoch.

Governance researchers who study blockchain governance models observe that Solana's SIMD process is more formalized and transparent than many competing networks and more open than a centralized company. At the same time, like most proof-of-stake governance systems, effective voting power is concentrated among large economic actors. Solana's governance is not DAO-based: SOL holders do not vote directly, and formal authority rests with the validator operator set.

Whether the current design represents adequate decentralization is a question each participant and observer should evaluate independently, informed by their own definition of what decentralization requires and what trade-offs they find acceptable.

Where to Find and Track Solana Improvement Documents

The official SIMD GitHub repository is the authoritative, real-time source for all SIMD proposals, their current status, and the full text of each proposal document.

How to navigate the repository:

• The repository's root directory lists all proposals by number
• Each proposal file is named with the SIMD number followed by a short description (for example, 0096-reward-full-priority-fee-to-validator.md)
• Status labels (Draft, Review, Last Call, Accepted, Activated, Final, Withdrawn, Rejected) appear in each proposal's preamble section
• To find proposals currently in active stages, filter by the "Review" or "Last Call" status markers in the preamble of each file

Community tracking resources:

• Solana Foundation forum (forum.solana.com): The primary venue for pre-submission community debate and proposal feedback
• Solana developer Discord (solana.com/community): Developer discussion channels where active SIMDs are frequently discussed
• validators.app: Tracks validator stake distribution and governance participation data, useful for monitoring how validator support for a SIMD is forming
• Solana Beach explorer: Provides on-chain data on validator software versions, which reflects the current state of stake-weighted adoption for any activating SIMD

SIMD statuses change as proposals move through the lifecycle. Any status information in this article should be verified against the live repository at time of reading.

Related Solana Architecture Resources

For governance roles and participation, see the SIMD governance explainer; architectural context appears in the guide to Solana's network architecture. The SOL price page provides current market context, while SOL Earn describes available staking-related products and their terms.

FAQ: Solana Improvement Documents (SIMD) Guide

What is a Solana Improvement Document (SIMD)?

A Solana Improvement Document (SIMD) is a formal written proposal for changing Solana's blockchain protocol, covering its economic parameters, validator behavior rules, and technical standards. SIMDs are publicly hosted on the official SIMD GitHub repository, follow a structured lifecycle from Draft to Final, and require stake-weighted validator consensus to activate. The definition section above provides full detail.

Who can submit a Solana Improvement Document?

Any developer, researcher, or community member can submit a SIMD with no permission required. Submission involves forking the official SIMD GitHub repository, drafting the proposal in the required format, and submitting a pull request. The Solana Foundation's editorial team reviews submissions for completeness and format, not for merit. Full submission steps appear in the participation guide above.

How do validators vote on a SIMD?

Validators vote by adopting or withholding the validator client software version (Agave or Firedancer) that implements the proposed change. Adopting the implementing version signals support; withholding the upgrade signals opposition. Votes are stake-weighted, meaning validators with more SOL delegated to them carry proportionally greater influence. The lifecycle section explains how the activation threshold works.

What are the stages of a SIMD proposal?

A SIMD passes through up to eight stages: Draft, Review, Last Call, Accepted, Activated, and Final, with three terminal states (Withdrawn, Rejected, Stagnant) possible at various points. The full stage-by-stage breakdown and lifecycle table appear in the SIMD lifecycle section above.

What SIMD changed Solana's inflation rate?

SIMD-0123 proposed adjusting Solana's inflation schedule by reducing the annual rate at which new SOL tokens are issued. Holders who do not stake experience slower dilution of their share of total supply when fewer new tokens are issued per year. The SIMD-0123 case study in the Landmark SIMDs section provides full detail.

How does a SIMD affect SOL token holders?

SIMDs that modify Solana's inflation schedule change the rate at which new SOL tokens are minted as staking rewards, directly affecting yields and supply dilution. SIMDs that change fee distribution rules (like SIMD-0096) affect validator revenue, which flows through to delegator staking returns. SOL holders do not hold a direct vote; formal voting authority belongs to validators. The token economics section explains these mechanisms in full.

What is the difference between a SIMD and an EIP?

Both SIMDs and Ethereum Improvement Proposals (EIPs) are formal systems for governing blockchain protocol changes, but they differ in voting mechanism. Solana uses explicit stake-weighted validator adoption with a defined quantitative threshold for activation. Ethereum's EIP process uses social consensus among core developers and client teams, with no single formal vote. The comparison table in the governance comparison section maps all differences.

Is Solana's governance decentralized?

Solana's governance is partially decentralized by design. The SIMD process allows open submission and public debate, and the Solana Foundation cannot unilaterally activate changes. However, effective voting power is concentrated among large validators, since governance is stake-weighted and a small number of large staking pools control a significant share of total delegated SOL. The decentralization assessment section presents the full balanced analysis.

Conclusion: Why the SIMD Process Matters for Solana's Future

The SIMD process is the formal mechanism through which Solana's protocol evolves, and understanding it matters for anyone whose holdings, applications, or infrastructure depend on the network. Three takeaways frame the practical significance of what this guide covers.

First, SIMDs are Solana's transparent, structured answer to the governance problem that all decentralized blockchains face: how to change the rules without a central authority. The SIMD lifecycle from Draft to Final gives every protocol change a documented, auditable trail accessible to anyone.

Second, specific SIMDs have already materially changed SOL tokenomics and validator economics. The landmark SIMDs covered in this guide, particularly SIMD-0096 and SIMD-0123, demonstrate that governance decisions translate directly into changes in fee income, staking yields, and token supply dynamics.

Third, the process is open. Developers can propose changes. Validators can signal votes. Token holders can follow discussions, contribute to community debates, and make delegation decisions that reflect their governance preferences. The official SIMD GitHub repository is the authoritative source for proposal status at any point in time.

The stakes of each governance decision grow as Solana's economic activity expands. Whether you hold SOL, build on Solana, or operate a validator, SIMD literacy is increasingly relevant to the decisions that affect your exposure to the network.