Mempool.space: built its whole identity on "no distractions, funded by the community." Then took $17M from a VC.
We're continuing our Crypto Block Explorers series with Mempool.space, the Bitcoin fee-market visualizer that redefined what a mempool view could look like. Real, disclosed genuine strengths: an explicit, disclosed no-ads, no-trackers, no-altcoins stance, genuine Tor support, and the most accessible self-hosting pathway we've found in this series, a one-click Raspberry Pi install. What we don't think should be set aside: in November 2025, the project incorporated "Mempool Holdings" in El Salvador, reportedly backed by a roughly $17 million round led by Fulgur Ventures, a real, disclosed shift for a project whose entire public identity was built on community funding. We weighted all of it below.
Our take, up front: Mempool.space is the flagship product of The Mempool Open Source Project, started in 2018 by developer softsimon and later developed together with Wiz. Real, disclosed genuinely strong, historically community-funded track record: grants and sponsorships from Square Crypto (roughly $100,000, April 2021), Gemini ($25,000), and Foundry, a Digital Currency Group subsidiary (1 BTC donation, August 2021). Real, disclosed genuinely explicit anti-tracking, anti-advertising stance, stated directly by the project itself: "we keep it free of distractions like advertising, altcoins, third-party trackers, etc. - we are funded by the community directly." Real, disclosed genuinely distinctive, independently-praised core feature: real-time mempool visualization and fee estimation described directly by Unchained Capital, a named Bitcoin financial-services integrator, as "reliable and accurate." Real, disclosed genuinely accessible self-hosting ecosystem: one-click installation on popular Bitcoin full-node distributions including Umbrel, RaspiBlitz, Start9, MyNode, and RoninDojo, down to a Raspberry Pi, the lowest-barrier self-hosting pathway we've found in this series. Real, disclosed major structural finding we found directly relevant to this category: in November 2025, the project incorporated "Mempool Holdings" in El Salvador and relocated its global headquarters there; in January 2026, reporting indicated this move was backed by an investment round of roughly $17 million led by Fulgur Ventures, a real, disclosed shift from the project's long-standing public "funded by the community" identity toward a VC-backed corporate structure. Real, disclosed feature controversy: an October 2024 update adding filters for Ordinals- and Runes-related transactions "led to debate within parts of the Bitcoin community." We weighted all of it below.
Real, disclosed genuinely long operating history since 2018, with a real, disclosed track record of community and industry grants (Square Crypto, Gemini, Foundry/DCG). Real, disclosed major structural change we found directly relevant to this category: in November 2025, the project incorporated "Mempool Holdings" in El Salvador, reportedly backed by a roughly $17 million round led by Fulgur Ventures, a real, disclosed shift from the project's long-standing "funded by the community" identity toward a VC-backed corporate structure. Real, disclosed feature controversy: the October 2024 addition of Ordinals/Runes filtering "led to debate within parts of the Bitcoin community."
Pros
- A long, disclosed track record of credible industry grants (Square Crypto, Gemini, Foundry) predates the recent VC round
Cons
- A disclosed $17M VC round and offshore incorporation sit in real tension with the project's own "funded by the community" messaging
- A disclosed community controversy over Ordinals/Runes filtering shows real, contested product decisions
Real, disclosed narrow, Bitcoin-focused scope, later expanded to include the Lightning Network and the Liquid Network, a real, disclosed limitation relative to broader multi-chain competitors in this series, though a deliberate, appropriate choice for its specialized fee-market focus.
Pros
- Coverage across Bitcoin, Lightning, and Liquid reflects real, disclosed ambition beyond base-layer Bitcoin alone
Cons
- No coverage of any chain outside the Bitcoin ecosystem itself
Real, disclosed genuinely strong, explicit anti-tracking stance: "we keep it free of distractions like advertising, altcoins, third-party trackers, etc." Real, disclosed genuinely distinctive privacy option: automatic Tor .onion support for fully private connectivity. What tempers this: using the public API means queries remain visible to mempool.space itself, a real, disclosed trade-off compared to the fully private self-hosted alternative.
Pros
- An explicit, disclosed no-advertising, no-third-party-tracker policy is a real, stated commitment, not just an absence of evidence
- Automatic Tor support for .onion connectivity is a genuine, disclosed technical privacy feature
Cons
- Public-API queries are disclosed as visible to mempool.space itself, unlike the fully private self-hosted option
Real, disclosed genuinely distinctive, technically necessary fee-market visualization: real-time mempool visualization, theoretical next-block construction, and fee estimation described directly by a named integrator, Unchained Capital, as "reliable and accurate."
Pros
- An independent, named integrator's public endorsement of fee-estimate accuracy is a real, credible trust signal
Cons
- The recently-added Ordinals/Runes filtering remains disclosed as contested within parts of the community
Real, disclosed genuinely accessible design, no account required, plus the most accessible self-hosting pathway found anywhere in this series: one-click installation on popular Bitcoin full-node distributions including Umbrel, RaspiBlitz, Start9, MyNode, and RoninDojo, down to a Raspberry Pi.
Pros
- One-click self-hosting on consumer-grade hardware is a genuinely unique, disclosed accessibility feature in this series
Cons
- Deeper features like the Enterprise tier and Accelerator service still require navigating a more commercial layer
Real, disclosed free public API and explorer, historically monetized through community and grant funding plus a disclosed Enterprise Sponsorship tier, alongside a newer, disclosed paid Mempool Accelerator transaction-acceleration service launched in July 2024.
Pros
- The core explorer, API, and self-hosting option all remain genuinely free
Cons
- Rate limits apply to the shared public API, disclosed directly as a reason to consider self-hosting instead
Real, disclosed genuinely broad self-hosting ecosystem integration across multiple full-node distributions, an MCP server for AI-agent access, and named industry integrations (Unchained Capital, Foundry) reflecting genuine, disclosed real-world adoption.
Pros
- Named, credible industry integrations reflect genuine trust beyond the Bitcoin hobbyist community alone
Cons
- The MCP server integration we found is a third-party package rather than a confirmed first-party tool
Genuinely excellent for its core purpose; self-host if the corporate shift bothers you.
Given the genuinely distinctive, independently-praised fee estimation and privacy design we found, we'd use Mempool.space with real confidence for its core purpose, and for anyone specifically uncomfortable with the new VC-backed corporate structure, the self-hosting option is a genuinely real, disclosed alternative, not just a talking point.
"Funded by the community" was true for years. We think readers deserve to know it's now also true that a VC wrote a check.
We want to be careful here, because we don't think Mempool.space did anything wrong by raising money, and $17 million can build a lot of infrastructure a Bitcoin fee visualizer genuinely needs. What we do think matters is the gap between the identity a project spent years building, "we keep it free of distractions... we are funded by the community directly," language still live on its own sponsorship page, and a very recent, real, disclosed shift toward a VC-backed holding company incorporated abroad. We don't think this makes Mempool.space untrustworthy. We think it makes the "funded by the community" framing incomplete in a way a reader deserves to know before taking it at face value. What keeps this score from falling further is that this project gives you an answer the others in this series mostly don't: if the corporate structure bothers you, you can run the whole thing yourself, on a Raspberry Pi, for the cost of the hardware. That's a genuinely real alternative, not just a talking point.
The scorecard above is deliberately general. Whether Mempool.space is right for you depends heavily on which of these you already are.
The Bitcoin user or developer who wants genuinely accurate, independently-praised fee estimation and mempool visualization
This is exactly where Mempool.space's real, disclosed technical strength delivers genuine, distinctive value.
The privacy-conscious hobbyist who self-hosts their own instance on a Raspberry Pi via Umbrel, RaspiBlitz, or Start9
Given the real, disclosed low-barrier self-hosting pathway, this specific option genuinely matters here.
The business exploring the Mempool Accelerator service or an Enterprise Sponsorship for production infrastructure
This is a real, disclosed commercial option worth evaluating on its own separate merits.
Anyone who specifically chose this project for its "funded by the community" identity without knowing about the 2025-2026 corporate changes
A real, disclosed shift toward VC-backed corporate structure makes this a poor fit for that specific assumption.
The scorecard covers the headline judgment calls. These four tables cover the specifics we didn't want to bury in prose; the corporate timeline laid out with dates, the public-API-vs-self-hosted trade-offs compared directly, the funding history from grants to VC round, and how all eleven Block Explorers reviewed so far compare.
The corporate timeline, laid out with dates
| Date | What happened |
|---|---|
| July 2024 | Launch of the paid Mempool Accelerator transaction-acceleration service |
| October 2024 | Ordinals/Runes filtering added, sparking community debate |
| November 2025 | Incorporation of Mempool Holdings in El Salvador; global HQ relocated there |
| January 2026 | Reporting indicates the move was backed by a ~$17M round led by Fulgur Ventures |
We're laying this out with dates because the pace of change here, four disclosed, significant developments within about 18 months, is itself worth a reader's attention.
Public API vs. self-hosted, compared directly
| Public API | Self-Hosted | |
|---|---|---|
| Rate limits | Yes, shared with all users | None |
| Privacy | Queries visible to mempool.space | Fully private |
| Uptime | Depends on mempool.space | You control it |
We're including this because it's a rare case of the ecosystem itself disclosing the exact trade-off a privacy-conscious reader would want to know before choosing which option to use.
The funding history, from grants to VC round
| Date | Source |
|---|---|
| April 2021 | Square Crypto grant, roughly $100,000 |
| 2021 | Gemini sponsorship, $25,000 |
| August 2021 | Foundry (a Digital Currency Group subsidiary), 1 BTC donation |
| January 2026 (reported) | ~$17 million round led by Fulgur Ventures |
We're tracing the full funding history because the scale of the most recent round is a real, disclosed departure from the grant-and-sponsorship pattern that came before it.
All eleven Block Explorers, compared so far
| Blockchain.com Explorer | Etherscan | Blockchair | Ethplorer | Blockscout | Solscan | SolanaFM | BscScan | OKLink | Tronscan | Mempool.space | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Core disclosed issue | Only 3 chains supported; its own privacy policy discloses sharing IP and device data with ad networks | A real, disclosed pattern of previously-free chain access narrowing over time | Third-party "zero tracking" claims sit alongside its own policy disclosing brief IP retention | Its operator's own ICO-funded token project is listed as one of its flagship API users | A "no personal data" marketing claim sits alongside a separate, more expansive commercial privacy policy | Solana-only scope, and Pro pricing gated behind a sales contact rather than published tiers | A rival explorer has publicly called it "largely unmaintained" since its acquirer took over | Single-chain scope, exclusively for BNB Smart Chain | Directly operated by OKX, a major exchange, with no disclosed pricing at all | Independent reporting links the underlying chain to illicit finance; its founder has a 2026 SEC settlement | A ~$17M VC round and offshore incorporation sit in tension with its "funded by the community" identity |
| Ownership | Backed by major VCs; raised ~$1.17B; disclosed a ~$270M 2022 default exposure | Founder-led since 2015; no exchange or major VC investor found | Founder-led since 2016; reported unfunded, no exchange or VC investor found | Operated by EverexIO, also behind the 2017 Everex ICO and its still-trading EVX token | VC-backed (1kx, Gnosis, ~$3M raised); headquartered in Seychelles | Founded 2021; acquired by Etherscan Jan 2024, carrying over the same founder-led, no-VC-investor structure | Founded 2021; acquired by Jupiter, a major Solana swap aggregator, Sep 2024 | Launched 2020 by Etherscan's own team; independently operated from Binance, the chain's creator | Launched 2014; first-party product of OKX, founded 2013 by Star Xu | Backed directly by the TRON Foundation, a Singapore nonprofit overseeing TRON since 2017 | Started 2018 by softsimon and Wiz; incorporated in El Salvador Nov 2025 with a ~$17M round led by Fulgur Ventures |
| Core strength | Long-standing, independently-praised usability for casual lookups | Industry-standard verified-contract database and unified 60+ chain API | Genuine Tor access, SQL-level data, and broad multi-chain coverage from an independent operator | A credible, independently-verifiable client roster including MyEtherWallet and MetaMask | Open-source, self-hostable, with the broadest EVM chain coverage found in this series | Technically necessary, human-readable decoding for roughly 200 Solana programs | A genuinely distinctive visual transaction-flow diagram feature, still functional today | Independent operation of the explorer for a chain its creator, Binance, did not build itself | The broadest, most architecturally diverse chain coverage (170+) found in this series | Genuinely distinctive, built-in governance and staking tools, plus a newly-launched MCP server | The most accessible self-hosting pathway (one-click Raspberry Pi install) found in this series |
| Our score | 54.75/100 | 76.0/100 | 72.75/100 | 50.5/100 | 79.25/100 | 63.75/100 | 46.5/100 | 62.5/100 | 56.5/100 | 50.25/100 | 61.75/100 |
Mempool.space's score reflects genuine credit for a genuinely accessible, privacy-forward, self-hostable design and independently-praised technical accuracy, weighed against a real, disclosed, recent shift away from the "community-funded" identity the project has publicly built itself around.
We don't just want to hand you our number; we want to show you how it sits next to what other sources have published. We're flagging directly that Bitcoin community sentiment toward Mempool.space is extremely positive and largely predates or hasn't fully caught up with the November 2025 corporate changes, giving those changes considerably less weight than our methodology does.
Our score lands modestly below the aggregated industry average; Bitcoin community sentiment credits the project's technical accuracy and long track record very heavily, while giving considerably less direct weight to the recent VC round and offshore incorporation than our methodology does.
| Source | Score | Type |
|---|
Scores compiled by our editorial team from publicly available reviews as of August 2026. "Editorial estimate" means the outlet didn't publish a single numeric score, so we converted their published verdict and sentiment into a comparable 100-point figure. Verify current figures directly with each source before citing them elsewhere.
The Mempool Open Source Project, started in 2018 by softsimon and later developed with Wiz. In November 2025, the project incorporated Mempool Holdings in El Salvador and relocated its global headquarters there, reportedly backed by a roughly $17 million round led by Fulgur Ventures.
That was historically true, with grants from Square Crypto, Gemini, and Foundry. As of late 2025, the project also has a disclosed VC-backed corporate structure, a real, disclosed shift that complicates the "funded by the community" framing still visible on its own sponsorship page.
The project states directly it keeps itself "free of distractions like advertising, altcoins, third-party trackers." It also supports automatic Tor .onion connectivity. Using the public API means your queries are visible to mempool.space itself, unlike a fully private self-hosted instance.
Yes, with one-click installation on popular Bitcoin full-node distributions including Umbrel, RaspiBlitz, Start9, MyNode, and RoninDojo, down to a Raspberry Pi, the lowest-barrier self-hosting option found in this series.
Bitcoin, the Lightning Network, and the Liquid Network. It does not cover chains outside the Bitcoin ecosystem, a deliberate scope given its fee-market specialization.
A paid transaction-acceleration service launched in July 2024, letting users pay to have a stuck or low-fee Bitcoin transaction confirmed faster.
Yes. An October 2024 update adding filters for Ordinals- and Runes-related transactions led to debate within parts of the Bitcoin community.
Mempool.space scores 61.75/100, reflecting genuine credit for a genuinely accessible, privacy-forward, self-hostable design and independently-praised technical accuracy, weighed against a real, disclosed shift away from its long-standing "community-funded" identity.
More Reviews
Suiscan – Crypto Block Explorer Review
Score: 52.75/100. Sui's developer-favorite explorer, genuinely deep in DeFi data, but no named operator was identifiable.
Read More
Blockchain.com – Crypto Block Explorer Review
Score: 54.75/100. VC-backed, casual-friendly, but only 3 chains and ad-network data sharing disclosed.
Read More
NearBlocks – Crypto Block Explorer Review
Score: 55.5/100. NEAR's grant-funded explorer, source-available under BSL 1.1, not fully open-source like NEAR's core code.
Read More
Etherscan – Crypto Block Explorer Review
Score: 76.0/100. Founder-led since 2015, with an industry-standard verified-contract database and unified 60+ chain API.
Read More