Framework to Evaluate Metaverse and Web3
Everywhere we turn, there's a new metaverse or Web3 debut. Microsoft recently announced a $68.7 BILLION cash purchase of Activision.
Like AI in 2013 and blockchain in 2014, NFT growth in 2021 feels like this year's metaverse and Web3 growth. We are all bombarded with information, conflicting signals, and a sensation of FOMO.
How can we evaluate the metaverse and Web3 in a noisy, new world? My framework for evaluating upcoming technologies and themes is shown below. I hope you will also find them helpful.
Understand the “pipes” in a new space.
Whatever people say, Metaverse and Web3 will have to coexist with the current Internet. Companies who host, move, and store data over the Internet have a lot of intriguing use cases in Metaverse and Web3, whether in infrastructure, data analytics, or compliance. Hence the following point.
## Understand the apps layer and their infrastructure.
Gaming, crypto exchanges, and NFT marketplaces would not exist today if not for technology that enables rapid app creation. Yes, according to Chainalysis and other research, 30–40% of Ethereum is self-hosted, with the rest hosted by large cloud providers. For Microsoft to acquire Activision makes strategic sense. It's not only about the games, but also the infrastructure that supports them.
Follow the money
Understanding how money and wealth flow in a complex and dynamic environment helps build clarity. Unless you are exceedingly wealthy, you have limited ability to significantly engage in the Web3 economy today. Few can just buy 10 ETH and spend it in one day. You must comprehend who benefits from the process, and how that 10 ETH circulates now and possibly tomorrow. Major holders and players control supply and liquidity in any market. Today, most Web3 apps are designed to increase capital inflow so existing significant holders can utilize it to create a nascent Web3 economy. When you see a new Metaverse or Web3 application, remember how money flows.
What is the use case?
What does the app do? If there is no clear use case with clear makers and consumers solving a real problem, then the euphoria soon fades, and the only stakeholders who remain enthused are those who have too much to lose.
Time is a major competition that is often overlooked.
We're only busier, but each day is still 24 hours. Using new apps may mean that time is lost doing other things. The user must be eager to learn. Metaverse and Web3 vs. our time? I don't think we know the answer yet (at least for working adults whose cost of time is higher).
I don't think we know the answer yet (at least for working adults whose cost of time is higher).
People and organizations need security and transparency.
For new technologies or apps to be widely used, they must be safe, transparent, and trustworthy. What does secure Metaverse and Web3 mean? This is an intriguing subject for both the business and public sectors. Cloud adoption grew in part due to improved security and data protection regulations.
The following frameworks can help analyze and understand new technologies and emerging technological topics, unless you are a significant investment fund with the financial ability to gamble on numerous initiatives and essentially form your own “index fund”.
I write on VC, startups, and leadership.
More on https://www.linkedin.com/in/joycejshen/ and https://joyceshen.substack.com/
This writing is my own opinion and does not represent investment advice.
More on Web3 & Crypto

Vitalik
4 years ago
An approximate introduction to how zk-SNARKs are possible (part 2)
If tasked with the problem of coming up with a zk-SNARK protocol, many people would make their way to this point and then get stuck and give up. How can a verifier possibly check every single piece of the computation, without looking at each piece of the computation individually? But it turns out that there is a clever solution.
Polynomials
Polynomials are a special class of algebraic expressions of the form:
- x+5
- x^4
- x^3+3x^2+3x+1
- 628x^{271}+318x^{270}+530x^{269}+…+69x+381
i.e. they are a sum of any (finite!) number of terms of the form cx^k
There are many things that are fascinating about polynomials. But here we are going to zoom in on a particular one: polynomials are a single mathematical object that can contain an unbounded amount of information (think of them as a list of integers and this is obvious). The fourth example above contained 816 digits of tau, and one can easily imagine a polynomial that contains far more.
Furthermore, a single equation between polynomials can represent an unbounded number of equations between numbers. For example, consider the equation A(x)+ B(x) = C(x). If this equation is true, then it's also true that:
- A(0)+B(0)=C(0)
- A(1)+B(1)=C(1)
- A(2)+B(2)=C(2)
- A(3)+B(3)=C(3)
And so on for every possible coordinate. You can even construct polynomials to deliberately represent sets of numbers so you can check many equations all at once. For example, suppose that you wanted to check:
- 12+1=13
- 10+8=18
- 15+8=23
- 15+13=28
You can use a procedure called Lagrange interpolation to construct polynomials A(x) that give (12,10,15,15) as outputs at some specific set of coordinates (eg. (0,1,2,3)), B(x) the outputs (1,8,8,13) on thos same coordinates, and so forth. In fact, here are the polynomials:
- A(x)=-2x^3+\frac{19}{2}x^2-\frac{19}{2}x+12
- B(x)=2x^3-\frac{19}{2}x^2+\frac{29}{2}x+1
- C(x)=5x+13
Checking the equation A(x)+B(x)=C(x) with these polynomials checks all four above equations at the same time.
Comparing a polynomial to itself
You can even check relationships between a large number of adjacent evaluations of the same polynomial using a simple polynomial equation. This is slightly more advanced. Suppose that you want to check that, for a given polynomial F, F(x+2)=F(x)+F(x+1) with the integer range {0,1…89} (so if you also check F(0)=F(1)=1, then F(100) would be the 100th Fibonacci number)
As polynomials, F(x+2)-F(x+1)-F(x) would not be exactly zero, as it could give arbitrary answers outside the range x={0,1…98}. But we can do something clever. In general, there is a rule that if a polynomial P is zero across some set S=\{x_1,x_2…x_n\} then it can be expressed as P(x)=Z(x)*H(x), where Z(x)=(x-x_1)*(x-x_2)*…*(x-x_n) and H(x) is also a polynomial. In other words, any polynomial that equals zero across some set is a (polynomial) multiple of the simplest (lowest-degree) polynomial that equals zero across that same set.
Why is this the case? It is a nice corollary of polynomial long division: the factor theorem. We know that, when dividing P(x) by Z(x), we will get a quotient Q(x) and a remainder R(x) is strictly less than that of Z(x). Since we know that P is zero on all of S, it means that R has to be zero on all of S as well. So we can simply compute R(x) via polynomial interpolation, since it's a polynomial of degree at most n-1 and we know n values (the zeros at S). Interpolating a polynomial with all zeroes gives the zero polynomial, thus R(x)=0 and H(x)=Q(x).
Going back to our example, if we have a polynomial F that encodes Fibonacci numbers (so F(x+2)=F(x)+F(x+1) across x=\{0,1…98\}), then I can convince you that F actually satisfies this condition by proving that the polynomial P(x)=F(x+2)-F(x+1)-F(x) is zero over that range, by giving you the quotient:
H(x)=\frac{F(x+2)-F(x+1)-F(x)}{Z(x)}
Where Z(x) = (x-0)*(x-1)*…*(x-98).
You can calculate Z(x) yourself (ideally you would have it precomputed), check the equation, and if the check passes then F(x) satisfies the condition!
Now, step back and notice what we did here. We converted a 100-step-long computation into a single equation with polynomials. Of course, proving the N'th Fibonacci number is not an especially useful task, especially since Fibonacci numbers have a closed form. But you can use exactly the same basic technique, just with some extra polynomials and some more complicated equations, to encode arbitrary computations with an arbitrarily large number of steps.
see part 3

Ren & Heinrich
3 years ago
200 DeFi Projects were examined. Here is what I learned.
I analyze the top 200 DeFi crypto projects in this article.
This isn't a study. The findings benefit crypto investors.
Let’s go!
A set of data
I analyzed data from defillama.com. In my analysis, I used the top 200 DeFis by TVL in October 2022.
Total Locked Value
The chart below shows platform-specific locked value.
14 platforms had $1B+ TVL. 65 platforms have $100M-$1B TVL. The remaining 121 platforms had TVLs below $100 million, with the lowest being $23 million.
TVLs are distributed Pareto. Top 40% of DeFis account for 80% of TVLs.
Compliant Blockchains
Ethereum's blockchain leads DeFi. 96 of the examined projects offer services on Ethereum. Behind BSC, Polygon, and Avalanche.
Five platforms used 10+ blockchains. 36 between 2-10 159 used 1 blockchain.
Use Cases for DeFi
The chart below shows platform use cases. Each platform has decentralized exchanges, liquid staking, yield farming, and lending.
These use cases are DefiLlama's main platform features.
Which use case costs the most? Chart explains. Collateralized debt, liquid staking, dexes, and lending have high TVLs.
The DeFi Industry
I compared three high-TVL platforms (Maker DAO, Balancer, AAVE). The columns show monthly TVL and token price changes. The graph shows monthly Bitcoin price changes.
Each platform's market moves similarly.
Probably because most DeFi deposits are cryptocurrencies. Since individual currencies are highly correlated with Bitcoin, it's not surprising that they move in unison.
Takeaways
This analysis shows that the most common DeFi services (decentralized exchanges, liquid staking, yield farming, and lending) also have the highest average locked value.
Some projects run on one or two blockchains, while others use 15 or 20. Our analysis shows that a project's blockchain count has no correlation with its success.
It's hard to tell if certain use cases are rising. Bitcoin's price heavily affects the entire DeFi market.
TVL seems to be a good indicator of a DeFi platform's success and quality. Higher TVL platforms are cheaper. They're a better long-term investment because they gain or lose less value than DeFis with lower TVLs.

Ben
3 years ago
The Real Value of Carbon Credit (Climate Coin Investment)
Disclaimer : This is not financial advice for any investment.
TL;DR
You might not have realized it, but as we move toward net zero carbon emissions, the globe is already at war.
According to the Paris Agreement of COP26, 64% of nations have already declared net zero, and the issue of carbon reduction has already become so important for businesses that it affects their ability to survive. Furthermore, the time when carbon emission standards will be defined and controlled on an individual basis is becoming closer.
Since 2017, the market for carbon credits has experienced extraordinary expansion as a result of widespread talks about carbon credits. The carbon credit market is predicted to expand much more once net zero is implemented and carbon emission rules inevitably tighten.
Hello! Ben here from Nonce Classic. Nonce Classic has recently confirmed the tremendous growth potential of the carbon credit market in the midst of a major trend towards the global goal of net zero (carbon emissions caused by humans — carbon reduction by humans = 0 ). Moreover, we too believed that the questions and issues the carbon credit market suffered from the last 30–40yrs could be perfectly answered through crypto technology and that is why we have added a carbon credit crypto project to the Nonce Classic portfolio. There have been many teams out there that have tried to solve environmental problems through crypto but very few that have measurable experience working in the carbon credit scene. Thus we have put in our efforts to find projects that are not crypto projects created for the sake of issuing tokens but projects that pragmatically use crypto technology to combat climate change by solving problems of the current carbon credit market. In that process, we came to hear of Climate Coin, a veritable carbon credit crypto project, and us Nonce Classic as an accelerator, have begun contributing to its growth and invested in its tokens. Starting with this article, we plan to publish a series of articles explaining why the carbon credit market is bullish, why we invested in Climate Coin, and what kind of project Climate Coin is specifically. In this first article let us understand the carbon credit market and look into its growth potential! Let’s begin :)
The Unavoidable Entry of the Net Zero Era
Net zero means... Human carbon emissions are balanced by carbon reduction efforts. A non-environmentalist may find it hard to accept that net zero is attainable by 2050. Global cooperation to save the earth is happening faster than we imagine.
In the Paris Agreement of COP26, concluded in Glasgow, UK on Oct. 31, 2021, nations pledged to reduce worldwide yearly greenhouse gas emissions by more than 50% by 2030 and attain net zero by 2050. Governments throughout the world have pledged net zero at the national level and are holding each other accountable by submitting Nationally Determined Contributions (NDC) every five years to assess implementation. 127 of 198 nations have declared net zero.
Each country's 1.5-degree reduction plans have led to carbon reduction obligations for companies. In places with the strictest environmental regulations, like the EU, companies often face bankruptcy because the cost of buying carbon credits to meet their carbon allowances exceeds their operating profits. In this day and age, minimizing carbon emissions and securing carbon credits are crucial.
Recent SEC actions on climate change may increase companies' concerns about reducing emissions. The SEC required all U.S. stock market companies to disclose their annual greenhouse gas emissions and climate change impact on March 21, 2022. The SEC prepared the proposed regulation through in-depth analysis and stakeholder input since last year. Three out of four SEC members agreed that it should pass without major changes. If the regulation passes, it will affect not only US companies, but also countless companies around the world, directly or indirectly.
Even companies not listed on the U.S. stock market will be affected and, in most cases, required to disclose emissions. Companies listed on the U.S. stock market with significant greenhouse gas emissions or specific targets are subject to stricter emission standards (Scope 3) and disclosure obligations, which will magnify investigations into all related companies. Greenhouse gas emissions can be calculated three ways. Scope 1 measures carbon emissions from a company's facilities and transportation. Scope 2 measures carbon emissions from energy purchases. Scope 3 covers all indirect emissions from a company's value chains.
The SEC's proposed carbon emission disclosure mandate and regulations are one example of how carbon credit policies can cross borders and affect all parties. As such incidents will continue throughout the implementation of net zero, even companies that are not immediately obligated to disclose their carbon emissions must be prepared to respond to changes in carbon emission laws and policies.
Carbon reduction obligations will soon become individual. Individual consumption has increased dramatically with improved quality of life and convenience, despite national and corporate efforts to reduce carbon emissions. Since consumption is directly related to carbon emissions, increasing consumption increases carbon emissions. Countries around the world have agreed that to achieve net zero, carbon emissions must be reduced on an individual level. Solutions to individual carbon reduction are being actively discussed and studied under the term Personal Carbon Trading (PCT).
PCT is a system that allows individuals to trade carbon emission quotas in the form of carbon credits. Individuals who emit more carbon than their allotment can buy carbon credits from those who emit less. European cities with well-established carbon credit markets are preparing for net zero by conducting early carbon reduction prototype projects. The era of checking product labels for carbon footprints, choosing low-emissions transportation, and worrying about hot shower emissions is closer than we think.
The Market for Carbon Credits Is Expanding Fearfully
Compliance and voluntary carbon markets make up the carbon credit market.
A Compliance Market enforces carbon emission allowances for actors. Companies in industries that previously emitted a lot of carbon are included in the mandatory carbon market, and each government receives carbon credits each year. If a company's emissions are less than the assigned cap and it has extra carbon credits, it can sell them to other companies that have larger emissions and require them (Cap and Trade). The annual number of free emission permits provided to companies is designed to decline, therefore companies' desire for carbon credits will increase. The compliance market's yearly trading volume will exceed $261B in 2020, five times its 2017 level.
In the Voluntary Market, carbon reduction is voluntary and carbon credits are sold for personal reasons or to build market participants' eco-friendly reputations. Even if not in the compliance market, it is typical for a corporation to be obliged to offset its carbon emissions by acquiring voluntary carbon credits. When a company seeks government or company investment, it may be denied because it is not net zero. If a significant shareholder declares net zero, the companies below it must execute it. As the world moves toward ESG management, becoming an eco-friendly company is no longer a strategic choice to gain a competitive edge, but an important precaution to not fall behind. Due to this eco-friendly trend, the annual market volume of voluntary emission credits will approach $1B by November 2021. The voluntary credit market is anticipated to reach $5B to $50B by 2030. (TSCVM 2021 Report)
In conclusion
This article analyzed how net zero, a target promised by countries around the world to combat climate change, has brought governmental, corporate, and human changes. We discussed how these shifts will become more obvious as we approach net zero, and how the carbon credit market would increase exponentially in response. In the following piece, let's analyze the hurdles impeding the carbon credit market's growth, how the project we invested in tries to tackle these issues, and why we chose Climate Coin. Wait! Jim Skea, co-chair of the IPCC working group, said,
“It’s now or never, if we want to limit global warming to 1.5°C” — Jim Skea
Join nonceClassic’s community:
Telegram: https://t.me/non_stock
Youtube: https://www.youtube.com/channel/UCqeaLwkZbEfsX35xhnLU2VA
Twitter: @nonceclassic
Mail us : general@nonceclassic.org
You might also like

Joseph Mavericks
3 years ago
The world's 36th richest man uses a 5-step system to get what he wants.
Ray Dalio's super-effective roadmap

Ray Dalio's $22 billion net worth ranks him 36th globally. From 1975 to 2011, he built the world's most successful hedge fund, never losing more than 4% from 1991 to 2020. (and only doing so during 3 calendar years).
Dalio describes a 5-step process in his best-selling book Principles. It's the playbook he's used to build his hedge fund, beat the markets, and face personal challenges.
This 5-step system is so valuable and well-explained that I didn't edit or change anything; I only added my own insights in the parts I found most relevant and/or relatable as a young entrepreneur. The system's overview:
Have clear goals
Identify and don’t tolerate problems
Diagnose problems to get at their root causes
Design plans that will get you around those problems
Do what is necessary to push through the plans to get results
If you follow these 5 steps in a virtuous loop, you'll almost always see results. Repeat the process for each goal you have.

1. Have clear goals
a) Prioritize: You can have almost anything, but not everything.
I started and never launched dozens of projects for 10 years because I was scattered. I opened a t-shirt store, traded algorithms, sold art on Instagram, painted skateboards, and tinkered with electronics. I decided to try blogging for 6 months to see where it took me. Still going after 3 years.
b) Don’t confuse goals with desires.
A goal inspires you to act. Unreasonable desires prevent you from achieving your goals.
c) Reconcile your goals and desires to decide what you want.
d) Don't confuse success with its trappings.
e) Never dismiss a goal as unattainable.
Always one path is best. Your perception of what's possible depends on what you know now. I never thought I'd make money writing online so quickly, and now I see a whole new horizon of business opportunities I didn't know about before.
f) Expectations create abilities.
Don't limit your abilities. More you strive, the more you'll achieve.
g) Flexibility and self-accountability can almost guarantee success.
Flexible people accept what reality or others teach them. Self-accountability is the ability to recognize your mistakes and be more creative, flexible, and determined.
h) Handling setbacks well is as important as moving forward.
Learn when to minimize losses and when to let go and move on.
2. Don't ignore problems
a) See painful problems as improvement opportunities.
Every problem, painful situation, and challenge is an opportunity. Read The Art of Happiness for more.
b) Don't avoid problems because of harsh realities.
Recognizing your weaknesses isn't the same as giving in. It's the first step in overcoming them.
c) Specify your issues.
There is no "one-size-fits-all" solution.
d) Don’t mistake a cause of a problem with the real problem.
"I can't sleep" is a cause, not a problem. "I'm underperforming" could be a problem.
e) Separate big from small problems.
You have limited time and energy, so focus on the biggest problems.
f) Don't ignore a problem.
Identifying a problem and tolerating it is like not identifying it.
3. Identify problems' root causes
a) Decide "what to do" after assessing "what is."
"A good diagnosis takes 15 to 60 minutes, depending on its accuracy and complexity. [...] Like principles, root causes recur in different situations.
b) Separate proximate and root causes.
"You can only solve problems by removing their root causes, and to do that, you must distinguish symptoms from disease."
c) Knowing someone's (or your own) personality can help you predict their behavior.
4. Design plans that will get you around the problems
a) Retrace your steps.
Analyze your past to determine your future.
b) Consider your problem a machine's output.
Consider how to improve your machine. It's a game then.
c) There are many ways to reach your goals.
Find a solution.
d) Visualize who will do what in your plan like a movie script.
Consider your movie's actors and script's turning points, then act accordingly. The game continues.
e) Document your plan so others can judge your progress.
Accountability boosts success.
f) Know that a good plan doesn't take much time.
The execution is usually the hardest part, but most people either don't have a plan or keep changing it. Don't drive while building the car. Build it first, because it'll be bumpy.
5. Do what is necessary to push through the plans to get results
a) Great planners without execution fail.
Life is won with more than just planning. Similarly, practice without talent beats talent without practice.
b) Work ethic is undervalued.
Hyper-productivity is praised in corporate America, even if it leads nowhere. To get things done, use checklists, fewer emails, and more desk time.
c) Set clear metrics to ensure plan adherence.
I've written about the OKR strategy for organizations with multiple people here. If you're on your own, I recommend the Wheel of Life approach. Both systems start with goals and tasks to achieve them. Then start executing on a realistic timeline.
If you find solutions, weaknesses don't matter.
Everyone's weak. You, me, Gates, Dalio, even Musk. Nobody will be great at all 5 steps of the system because no one can think in all the ways required. Some are good at analyzing and diagnosing but bad at executing. Some are good planners but poor communicators. Others lack self-discipline.
Stay humble and ask for help when needed. Nobody has ever succeeded 100% on their own, without anyone else's help. That's the paradox of individual success: teamwork is the only way to get there.
Most people won't have the skills to execute even the best plan. You can get missing skills in two ways:
Self-taught (time-consuming)
Others' (requires humility) light
On knowing what to do with your life
“Some people have good mental maps and know what to do on their own. Maybe they learned them or were blessed with common sense. They have more answers than others. Others are more humble and open-minded. […] Open-mindedness and mental maps are most powerful.” — Ray Dalio
I've always known what I wanted to do, so I'm lucky. I'm almost 30 and have always had trouble executing. Good thing I never stopped experimenting, but I never committed to anything long-term. I jumped between projects. I decided 3 years ago to stick to one project for at least 6 months and haven't looked back.
Maybe you're good at staying focused and executing, but you don't know what to do. Maybe you have none of these because you haven't found your purpose. Always try new projects and talk to as many people as possible. It will give you inspiration and ideas and set you up for success.
There is almost always a way to achieve a crazy goal or idea.
Enjoy the journey, whichever path you take.
Ash Parrish
3 years ago
Sonic Prime and indie games on Netflix
Netflix will stream Spiritfarer, Raji: An Ancient Epic, and Lucky Luna.
Netflix's Geeked Week brought a slew of announcements. The flurry of reveals for The Sandman, The Umbrella Academy season 3, One Piece, and more also included game and game-adjacent announcements.
Netflix released a teaser for Cuphead season 2 ahead of its August premiere, featuring more of Grey DeLisle's Ms. Chalice. DOTA: Dragon's Blood season 3 hits Netflix in August. Tekken, the fighting game that throws kids off cliffs, gets an anime, Tekken: Bloodline.
Netflix debuted a clip of Sonic Prime before Sonic Origins in June and Sonic Frontiers in 2022.
Castlevania: Nocturne will follow Richter Belmont.
Netflix is reviving licensed games with titles based on its shows. There's a Queen's Gambit chess game, a Shadow and Bone RPG, a La Casa de Papel heist adventure, and a Too Hot to Handle game where a pregnant woman must choose between stabbing her cheating ex or forgiving him.
Riot's rhythm platformer Hextech Mayhem debuted on Netflix last year, and now Netflix is adding games from Devolver Digital. Reigns: Three Kingdoms is a card game that lets players choose the fate of Three Kingdoms-era China by swiping left or right on cards. Spiritfarer, the "cozy game about death" from 2020, and Raji: An Ancient Epic are coming to Netflix. Poinpy, a vertical climber from the creator of Downwell, is now on Netflix.
Desta: The Memories Between is a turn-based strategy game set in dreams and memories.
Snowman's Lucky Luna will also be added soon.
With these games, Netflix is expanding beyond dinky mobile games — it plans to have 50 by the end of the year — and could be a serious platform for indies that want to expand into mobile. It takes gaming seriously.
James Brockbank
3 years ago
Canonical URLs for Beginners
Canonicalization and canonical URLs are essential for SEO, and improper implementation can negatively impact your site's performance.
Canonical tags were introduced in 2009 to help webmasters with duplicate or similar content on multiple URLs.
To use canonical tags properly, you must understand their purpose, operation, and implementation.
Canonical URLs and Tags
Canonical tags tell search engines that a certain URL is a page's master copy. They specify a page's canonical URL. Webmasters can avoid duplicate content by linking to the "canonical" or "preferred" version of a page.
How are canonical tags and URLs different? Can these be specified differently?
Tags
Canonical tags are found in an HTML page's head></head> section.
<link rel="canonical" href="https://www.website.com/page/" />These can be self-referencing or reference another page's URL to consolidate signals.
Canonical tags and URLs are often used interchangeably, which is incorrect.
The rel="canonical" tag is the most common way to set canonical URLs, but it's not the only way.
Canonical URLs
What's a canonical link? Canonical link is the'master' URL for duplicate pages.
In Google's own words:
A canonical URL is the page Google thinks is most representative of duplicate pages on your site.
— Google Search Console Help
You can indicate your preferred canonical URL. For various reasons, Google may choose a different page than you.
When set correctly, the canonical URL is usually your specified URL.
Canonical URLs determine which page will be shown in search results (unless a duplicate is explicitly better for a user, like a mobile version).
Canonical URLs can be on different domains.
Other ways to specify canonical URLs
Canonical tags are the most common way to specify a canonical URL.
You can also set canonicals by:
Setting the HTTP header rel=canonical.
All pages listed in a sitemap are suggested as canonicals, but Google decides which pages are duplicates.
Redirects 301.
Google recommends these methods, but they aren't all appropriate for every situation, as we'll see below. Each has its own recommended uses.
Setting canonical URLs isn't required; if you don't, Google will use other signals to determine the best page version.
To control how your site appears in search engines and to avoid duplicate content issues, you should use canonicalization effectively.
Why Duplicate Content Exists
Before we discuss why you should use canonical URLs and how to specify them in popular CMSs, we must first explain why duplicate content exists. Nobody intentionally duplicates website content.
Content management systems create multiple URLs when you launch a page, have indexable versions of your site, or use dynamic URLs.
Assume the following URLs display the same content to a user:
A search engine sees eight duplicate pages, not one.
URLs #1 and #2: the CMS saves product URLs with and without the category name.
#3, #4, and #5 result from the site being accessible via HTTP, HTTPS, www, and non-www.
#6 is a subdomain mobile-friendly URL.
URL #7 lacks URL #2's trailing slash.
URL #8 uses a capital "A" instead of a lowercase one.
Duplicate content may also exist in URLs like:
https://www.website.com
https://www.website.com/index.php
Duplicate content is easy to create.
Canonical URLs help search engines identify different page variations as a single URL on many sites.
SEO Canonical URLs
Canonical URLs help you manage duplicate content that could affect site performance.
Canonical URLs are a technical SEO focus area for many reasons.
Specify URL for search results
When you set a canonical URL, you tell Google which page version to display.
Which would you click?
https://www.domain.com/page-1/
https://www.domain.com/index.php?id=2
First, probably.
Canonicals tell search engines which URL to rank.
Consolidate link signals on similar pages
When you have duplicate or nearly identical pages on your site, the URLs may get external links.
Canonical URLs consolidate multiple pages' link signals into a single URL.
This helps your site rank because signals from multiple URLs are consolidated into one.
Syndication management
Content is often syndicated to reach new audiences.
Canonical URLs consolidate ranking signals to prevent duplicate pages from ranking and ensure the original content ranks.
Avoid Googlebot duplicate page crawling
Canonical URLs ensure that Googlebot crawls your new pages rather than duplicated versions of the same one across mobile and desktop versions, for example.
Crawl budgets aren't an issue for most sites unless they have 100,000+ pages.
How to Correctly Implement the rel=canonical Tag
Using the header tag rel="canonical" is the most common way to specify canonical URLs.
Adding tags and HTML code may seem daunting if you're not a developer, but most CMS platforms allow canonicals out-of-the-box.
These URLs each have one product.
How to Correctly Implement a rel="canonical" HTTP Header
A rel="canonical" HTTP header can replace canonical tags.
This is how to implement a canonical URL for PDFs or non-HTML documents.
You can specify a canonical URL in your site's.htaccess file using the code below.
<Files "file-to-canonicalize.pdf"> Header add Link "< http://www.website.com/canonical-page/>; rel=\"canonical\"" </Files>301 redirects for canonical URLs
Google says 301 redirects can specify canonical URLs.
Only the canonical URL will exist if you use 301 redirects. This will redirect duplicates.
This is the best way to fix duplicate content across:
HTTPS and HTTP
Non-WWW and WWW
Trailing-Slash and Non-Trailing Slash URLs
On a single page, you should use canonical tags unless you can confidently delete and redirect the page.
Sitemaps' canonical URLs
Google assumes sitemap URLs are canonical, so don't include non-canonical URLs.
This does not guarantee canonical URLs, but is a best practice for sitemaps.
Best-practice Canonical Tag
Once you understand a few simple best practices for canonical tags, spotting and cleaning up duplicate content becomes much easier.
Always include:
One canonical URL per page
If you specify multiple canonical URLs per page, they will likely be ignored.
Correct Domain Protocol
If your site uses HTTPS, use this as the canonical URL. It's easy to reference the wrong protocol, so check for it to catch it early.
Trailing slash or non-trailing slash URLs
Be sure to include trailing slashes in your canonical URL if your site uses them.
Specify URLs other than WWW
Search engines see non-WWW and WWW URLs as duplicate pages, so use the correct one.
Absolute URLs
To ensure proper interpretation, canonical tags should use absolute URLs.
So use:
<link rel="canonical" href="https://www.website.com/page-a/" />And not:
<link rel="canonical" href="/page-a/" />If not canonicalizing, use self-referential canonical URLs.
When a page isn't canonicalizing to another URL, use self-referencing canonical URLs.
Canonical tags refer to themselves here.
Common Canonical Tags Mistakes
Here are some common canonical tag mistakes.
301 Canonicalization
Set the canonical URL as the redirect target, not a redirected URL.
Incorrect Domain Canonicalization
If your site uses HTTPS, don't set canonical URLs to HTTP.
Irrelevant Canonicalization
Canonicalize URLs to duplicate or near-identical content only.
SEOs sometimes try to pass link signals via canonical tags from unrelated content to increase rank. This isn't how canonicalization should be used and should be avoided.
Multiple Canonical URLs
Only use one canonical tag or URL per page; otherwise, they may all be ignored.
When overriding defaults in some CMSs, you may accidentally include two canonical tags in your page's <head>.
Pagination vs. Canonicalization
Incorrect pagination can cause duplicate content. Canonicalizing URLs to the first page isn't always the best solution.
Canonicalize to a 'view all' page.
How to Audit Canonical Tags (and Fix Issues)
Audit your site's canonical tags to find canonicalization issues.
SEMrush Site Audit can help. You'll find canonical tag checks in your website's site audit report.
Let's examine these issues and their solutions.
No Canonical Tag on AMP
Site Audit will flag AMP pages without canonical tags.
Canonicalization between AMP and non-AMP pages is important.
Add a rel="canonical" tag to each AMP page's head>.
No HTTPS redirect or canonical from HTTP homepage
Duplicate content issues will be flagged in the Site Audit if your site is accessible via HTTPS and HTTP.
You can fix this by 301 redirecting or adding a canonical tag to HTTP pages that references HTTPS.
Broken canonical links
Broken canonical links won't be considered canonical URLs.
This error could mean your canonical links point to non-existent pages, complicating crawling and indexing.
Update broken canonical links to the correct URLs.
Multiple canonical URLs
This error occurs when a page has multiple canonical URLs.
Remove duplicate tags and leave one.
Canonicalization is a key SEO concept, and using it incorrectly can hurt your site's performance.
Once you understand how it works, what it does, and how to find and fix issues, you can use it effectively to remove duplicate content from your site.
