Joseph Poon and Thaddeus Dryja showed slides to SF Bitcoin Devs on February 23, 20153. On February 28, 2015, they posted a paper on lightning.network1. An Internet Archive copy of the site, taken at 16:27 UTC on February 28, lists it as "Paper Version 0.5". The draft opened with a big claim. “The bitcoin protocol can encompass the global financial transaction volume in all electronic payment systems today, without a single custodial 3rd party holding funds or requiring participants to have any more than a computer on a home broadband connection,” Poon and Dryja wrote2.
That claim became the Lightning Network. This piece follows the paper, the fix it needed from Bitcoin, and the numbers its public network posts today.
What the paper asked of Bitcoin
The problem was room. Bitcoin handled "around 7 transactions per second with a 1 megabyte block limit," the draft said2. Visa was "believed to do 45,000 peak transactions per second". Matching Visa on the blockchain would take blocks of nearly 8 gigabytes every ten minutes, the authors wrote.
Their answer was a payment channel. Two people lock funds in one shared entry on the blockchain5. Then they swap signed updates between themselves and settle the final balance later. Link enough channels, and a payment can hop across strangers to reach its target.
One condition sat inside the abstract. Payments between untrusted parties would work “If Bitcoin transactions can be signed with a new sighash type which addresses malleability,” the draft said2. Malleability lets someone alter a transaction's ID before it confirms7. A channel depends on transactions that point at other, unconfirmed transactions.
Both sides, in their own words
Did the network deliver?
“There are no public metrics on how many people use Lightning, so critics point at metrics such as node count, channels, and capacity, which have plateaued over the past year and thus give a false impression that Lightning’s adoption may be stagnating or declining”
“Effective now, I'm halting my involvement with the development of the lightning network and its implementations, including coordinating the handling of security issues at the protocol level”
The morning in Hong Kong
A different team supplied the fix. Scaling Bitcoin met in Hong Kong on December 7, 20156. Pieter Wuille gave the first talk of the day at 09:05, Hong Kong time, with "Segregated witness and its impact on scalability". Dryja followed at 09:30 with "Overview of BIPs necessary for Lightning". Poon spoke at 09:55.
Segregated witness, or SegWit, moves signatures out of the data that sets a transaction's ID7. BIP141, the formal proposal, puts that result first: "Nonintentional malleability becomes impossible". The proposal also names the payoff for chains of unconfirmed transactions: "an important feature for offchain protocols such as the Lightning Network". SegWit took effect at block 481,824, mined at 01:57 UTC on August 24, 20178.
What the revision changed
Poon and Dryja dated a revised paper January 14, 20164. Draft 0.5 ran 22 pages. Version 0.5.9.2 runs 592. Its Visa figure grew to “47,000 peak transactions per second (tps) on its network during the 2013 holidays”. Draft 0.5.9.1, dated November 20, 2015, already ran 59 pages with that figure17.
One number shrank by a factor of 1,000. In February 2015, 8-gigabyte blocks would add "over 400 petabytes per year," the draft said2. Poon and Dryja's 2016 version says "over 400 terabytes of data per year"4. Eight gigabytes every ten minutes comes to about 420 terabytes a year, so the change fixed the unit. The fix first appears in the November 2015 draft17.
Mike Hearn, a former Bitcoin developer, published his exit essay that same day16. He described a view he credited to Gregory Maxwell: Bitcoin “should become a sort of settlement layer for some vaguely defined, as yet un-created non-blockchain based system”. The paper Poon and Dryja dated January 14 describes payments that move off the blockchain and settle on it4.
What the coverage missed
Press reports in December 2015 read SegWit as a block size story. CoinDesk called it "a novel workaround to the block size issue" on December 815. Pete Rizzo's report quoted Dryja on where signatures go and on soft forks. Its passage on malleability pointed back to Mt. Gox.
So where was Lightning in that coverage? The word appeared once, as Dryja's job title15. His payment channels got one sentence, under the subhead "Tangential benefits". BIP141 names the Lightning Network outright7.
The network in numbers
mempool.space publishes daily counts for the public Lightning network back to March 21, 20189. Public means channels announced to the network, and the nodes that hold them. Its readings for August 30 of each year show the arc. Channels stood at 29,152 in 2019 and 81,755 in 2022. On August 30, 2026, they stood at 32,518, which is 60 percent below the 2022 reading. Nodes rose from 4,741 in 2019 to 15,839 in 2022, then reached 16,230.
Public channels on Bitcoin's Lightning Network fell from 81,755 in 2022 to 32,518 in 2026
Public channels and public nodes on the Lightning Network, counted on Aug. 30 of each year
- Public channels
- Public nodes
- Height: Count
Source: mempool.space [9].
Read the chart as a table
| Item | Public channels | Public nodes |
|---|---|---|
| 2019 | 29,152 | 4,741 |
| 2020 | 29,981 | 5,939 |
| 2021 | 62,385 | 13,541 |
| 2022 | 81,755 | 15,839 |
| 2023 | 67,146 | 15,404 |
| 2024 | 48,483 | 12,786 |
| 2025 | 41,541 | 17,129 |
| 2026 | 32,518 | 16,230 |
Channels peaked at 82,825 on March 28, 20229. Capacity, the bitcoin locked in public channels, took another path. Public capacity set a record of 5,851.48 BTC on December 28, 2025. By August 30, 2026, it read 3,753.75 BTC. mempool.space answers from several servers, and their files differ slightly10. These figures match one copy, which ends on August 30, 2026.
Month-end readings from August 2022 to November 2024 show a long plateau9. That stretch is the longest unbroken run of months in the file. Capacity ended June 2023 at 5,489.56 BTC. September 2023 closed at 4,508.50 BTC, and October 2023 at 5,339.23 BTC.
Public Lightning capacity fell to 4,508 BTC in September 2023 and rose to 5,339 in October
Bitcoin locked in public Lightning channels at each month's last daily reading, in BTC
- October 2023, when Antoine Riard quit Lightning work: 5,339 BTC
- Other months, each at its last daily reading
- Height: Capacity, BTC
Source: mempool.space [9].
Read the chart as a table
| Item | Value |
|---|---|
| Aug 2022 | 4,616 BTC |
| Sep 2022 | 4,924 BTC |
| Oct 2022 | 5,147 BTC |
| Nov 2022 | 5,127 BTC |
| Dec 2022 | 5,156 BTC |
| Jan 2023 | 5,327 BTC |
| Feb 2023 | 5,458 BTC |
| Mar 2023 | 5,437 BTC |
| Apr 2023 | 5,457 BTC |
| May 2023 | 5,423 BTC |
| Jun 2023 | 5,490 BTC |
| Jul 2023 | 4,788 BTC |
| Aug 2023 | 4,722 BTC |
| Sep 2023 | 4,508 BTC |
| Oct 2023 | 5,339 BTC |
| Nov 2023 | 5,101 BTC |
| Dec 2023 | 5,034 BTC |
| Jan 2024 | 4,955 BTC |
| Feb 2024 | 4,581 BTC |
| Mar 2024 | 4,648 BTC |
| Apr 2024 | 4,802 BTC |
| May 2024 | 4,935 BTC |
| Jun 2024 | 5,181 BTC |
| Jul 2024 | 4,940 BTC |
| Aug 2024 | 5,138 BTC |
| Sep 2024 | 5,167 BTC |
| Oct 2024 | 5,275 BTC |
| Nov 2024 | 5,281 BTC |
The case for Lightning's reach
River, a bitcoin broker, argues that these counts measure the wrong thing. Sam Wouters wrote its research report, published October 10, 202314. “There are no public metrics on how many people use Lightning, so critics point at metrics such as node count, channels, and capacity, which have plateaued over the past year and thus give a false impression that Lightning’s adoption may be stagnating or declining,” the report says.
Wouters then states River's finding. “Our research shows the opposite, as growth in the number of users, transactions, and volume has been accelerating significantly over the past years,” the report says14. Its title says the Lightning Network grew by 1,212 percent in two years. River's report also maps 173 companies across 28 categories in the Lightning industry.
The case against
Antoine Riard, a Bitcoin and Lightning developer, posted a full disclosure on October 16, 202311. His post described a new attack, replacement cycling, aimed at nodes that forward payments. Mitigations had shipped in LDK, Eclair, LND and Core-Lightning. He wrote that the attacks had gone unobserved in the wild for about ten months.
On October 20, 2023, he quit Lightning work. “Effective now, I'm halting my involvement with the development of the lightning network and its implementations, including coordinating the handling of security issues at the protocol level,” Riard wrote12. “I think this new class of replacement cycling attacks puts lightning in a very perilous position, where only a sustainable fix can happen at the base-layer, e.g adding a memory-intensive history of all-seen transactions or some consensus upgrade,” he added.
He put the public network at about 5,355 BTC12. mempool.space read 5,356.20 BTC on October 16, 2023, the day of his first post9. Vishal Chawla reported his exit for The Block on October 23, 202313.
What to watch
Each side needs a different number. River's case needs payment counts that keep rising while public channels shrink14. Riard's case points to a change in Bitcoin itself, which he said needs the buy-in of the whole community12.
mempool.space's next reading will show whether public channels hold near 32,5189. On lightning.network today, the paper's link reads "DRAFT Version 0.5.9.1"5. The PDF behind it is version 0.5.9.2, dated January 14, 20164.
Sources
- Joseph Poon and Thaddeus Dryja, "The Bitcoin Lightning Network" (home page), Lightning Network, Internet Archive capture of Feb. 28, 2015, 16:27 UTC, https://web.archive.org/web/20150228162703/http://lightning.network/
- Joseph Poon and Thaddeus Dryja, "The Bitcoin Lightning Network, DRAFT Version 0.5," Lightning Network, Feb. 28, 2015 (Internet Archive copy), https://web.archive.org/web/20150301065655/http://lightning.network/lightning-network-paper-DRAFT-0.5.pdf
- Joseph Poon and Thaddeus Dryja, "Lightning Network" (slides), SF Bitcoin Devs, Feb. 23, 2015 (Internet Archive copy), https://web.archive.org/web/20150301190111/http://lightning.network/lightning-network.pdf
- Joseph Poon and Thaddeus Dryja, "The Bitcoin Lightning Network: Scalable Off-Chain Instant Payments," DRAFT Version 0.5.9.2, Lightning Network, Jan. 14, 2016, https://lightning.network/lightning-network-paper.pdf
- Lightning Network, "Lightning Network: Scalable, Instant Bitcoin/Blockchain Transactions," read Oct. 13, 2026, https://lightning.network/
- Scaling Bitcoin, "Scaling Bitcoin 2015 Phase II, December 6th-7th, Hong Kong" (schedule), https://scalingbitcoin.org/hongkong2015/
- Eric Lombrozo, Johnson Lau and Pieter Wuille, "BIP 141: Segregated Witness (Consensus layer)," GitHub (bitcoin/bips), assigned Dec. 21, 2015, https://github.com/bitcoin/bips/blob/master/bip-0141.mediawiki
- mempool.space, "Block 481,824" (block API), read Oct. 13, 2026, https://mempool.space/api/block/0000000000000000001c8018d9cb3b742ef25114f27563e3fc4a1902167f9893
- mempool.space, "Lightning Network statistics, all history," read Oct. 13, 2026, https://mempool.space/api/v1/lightning/statistics/all
- mempool.space, "Lightning Network statistics, latest reading," read Oct. 13, 2026, https://mempool.space/api/v1/lightning/statistics/latest
- Antoine Riard, "Full Disclosure: CVE-2023-40231 / CVE-2023-40232 / CVE-2023-40233 / CVE-2023-40234 'All your mempool are belong to us'," Bitcoin Development Mailinglist, Oct. 16, 2023, https://mirror.b10c.me/lists/bitcoindev/CALZpt+GdyfDotdhrrVkjTALg5DbxJyiS8ruO2S7Ggmi9Ra5B9g@mail.gmail.com/
- Antoine Riard, "Re: Full Disclosure: CVE-2023-40231 / CVE-2023-40232 / CVE-2023-40233 / CVE-2023-40234 'All your mempool are belong to us'," Bitcoin Development Mailinglist, Oct. 20, 2023, https://mirror.b10c.me/lists/bitcoindev/CALZpt+G-eLLShrJckLG1UMDQ9tMGzqP1pBsUpEZ+82e9wHZGYw@mail.gmail.com/
- Vishal Chawla, "Developer exposed potential security issue on the Lightning Network," The Block, Oct. 23, 2023, https://www.theblock.co/post/258871/developer-exposed-potential-security-issue-on-the-lightning-network
- Sam Wouters, "The Lightning Network Grew by 1212% in 2 Years," River, Oct. 10, 2023, https://river.com/content/the-lightning-network-in-2023
- Pete Rizzo, "Is Segregated Witness the Answer to Bitcoin's Block Size Debate?," CoinDesk, Dec. 8, 2015 (Internet Archive copy), https://web.archive.org/web/20151209191346/http://www.coindesk.com/segregated-witness-bitcoin-block-size-debate/
- Mike Hearn, "The resolution of the Bitcoin experiment," blog.plan99.net, Jan. 14, 2016 (Internet Archive copy), https://web.archive.org/web/20170607220742/https://blog.plan99.net/the-resolution-of-the-bitcoin-experiment-dabb30201f7
- Joseph Poon and Thaddeus Dryja, "The Bitcoin Lightning Network: Scalable Off-Chain Instant Payments," DRAFT Version 0.5.9.1, Lightning Network, Nov. 20, 2015 (Internet Archive copy of Jan. 13, 2016), https://web.archive.org/web/20160113014623/http://lightning.network/lightning-network-paper.pdf