Flow Blockchain Guide: How It Launched With NBA Top Shot

Flow is a layer-1 blockchain built by Dapper Labs, the company behind NBA Top Shot and CryptoKitties. Its stated purpose is to host consumer applications such as games, sports collectibles and fan experiences, where users should not need to understand gas tokens, seed phrases or network congestion to take part.

Flow is a separate chain from Ethereum. Assets move between the two through bridges rather than automatically, so a token on one network is not the same as a token on the other unless a bridge says it is.

A few terms help when reading Flow material:

• Layer-1: a base chain with its own validators and consensus, not a rollup that settles on another chain.
• Smart contract: code stored on a chain that runs when someone calls it.
• Moment: the name Top Shot uses for each NFT, which is a short video clip of a play.
• FLOW: the native token used for transaction fees, staking and governance.

Whether Flow matters to you depends on what you want to do. Collectors care about the Top Shot marketplace and wallet setup, builders care about Cadence and tooling, and stakers care about the FLOW token rules. The rest of this guide covers each path in turn.

NBA Top Shot launched in 2020 as a collectibles product in which fans buy packs that contain moments, short clips of NBA highlights. Each moment is a non-fungible token recorded on Flow, so ownership and transfer history can be checked on the chain rather than only in the app.

Dapper Labs chose Flow because the chain was designed for high-volume consumer use. A popular collectibles app creates many small transactions in short bursts, and the team needed a network that could handle that without fees and waiting times that would drive casual buyers away.

Since launch, the app has added features over time. Reporting in 2021 described moments being sold at live games, and reporting in 2023 described native mobile apps for buying moments. These details show how the product widened its reach, but the current options are the ones listed on Top Shot's official site.

The lasting lesson is twofold. Top Shot showed that Flow could support a large consumer app, and it also showed that a single flagship app can account for most of a chain's activity. Anyone evaluating Flow today should look at how many different apps are active, not only at one well-known product.

Flow does not handle every task in one kind of node. Its design splits work into five node roles: collection nodes gather transactions, consensus nodes order them, execution nodes run the transactions, verification nodes check the results, and access nodes serve data to apps and users.

The main idea is that each step can scale on its own. If transaction volume grows, more collection or execution capacity can be added without forcing every node to do everything. This is a different approach from chains where every validator both orders and executes every transaction.

The design has trade-offs:

• Running a node is more complex than running a single-role validator.
• Fewer operators at some roles can make the network more concentrated, so the number of node operators matters.
• Users rely on access nodes and public endpoints, which means app developers must choose their providers with care.

To judge decentralisation, check the current number of validators and their distribution in Flow's public network dashboards. Do not assume that a design goal guarantees the current state of the network.

Flow apps are written mainly in Cadence, a smart contract language designed for Flow. Its central feature is the resource model, which treats valuable items such as NFTs as objects that cannot be copied or silently destroyed. This suits collectibles, because a moment can only move by an explicit transfer.

Cadence also separates reads from writes. Read-only queries, called scripts, do not change state and do not require a signed transaction. State-changing actions, called transactions, must be signed and paid for. Keeping these two paths distinct makes apps easier to audit.

A typical path for a developer looks like this:

1. Learn Cadence basics and the resource model.
2. Run code against the local emulator to test contracts.
3. Deploy to the test network and check behaviour with test accounts.
4. Move to the main network only after an audit and a careful review of access controls.

Flow also provides client libraries for web front ends and a developer portal with tutorials. Account linking, which lets an app sign users in with a Flow wallet, is covered in those tutorials and is a common starting point for new projects.

A Flow account is a container for keys, balances and smart contracts. One account can hold multiple keys with different permissions, which is useful for apps that need to separate day-to-day signing from higher-risk actions. Account keys can be added or revoked, so a compromised key does not have to mean losing the whole account.

For Top Shot collectors, the wallet setup has changed over time. Official guidance has described a sequence along these lines:

• Create a Flow wallet.
• Link your Dapper wallet to your Flow wallet.
• Move your moments to the Flow wallet.

Follow the current instructions on Top Shot's official help pages, because these steps can change. Before moving any item, confirm the destination address character by character, and make a small test transfer when the process allows it.

Account linking is also used by third-party apps. When you connect a Flow wallet to an app, you are usually granting it permission to request signatures for specific actions. Read the permission prompt and disconnect the app when you are finished with it.

FLOW is the native token of the network. It is used to pay transaction fees, to stake for network security and to take part in governance. Holders who stake can delegate to node operators, and the rewards depend on the network's current rules and the operator they choose.

Fee amounts and staking rewards change with network conditions and protocol updates, so this guide does not state them. Check Flow's official documentation and staking pages for the current figures. Be wary of any site that quotes a fixed yield without showing where the figure comes from.

Before you stake, review these points:

• The unstaking process can involve a waiting period, so you may not be able to sell immediately.
• The operator you delegate to takes on operational risk, and poor performance can reduce rewards.
• Token prices can fall even when staking rewards are paid in FLOW, so rewards in tokens do not equal a stable return.

Never stake more than you can afford to have locked for a period of time. If you hold FLOW through an exchange or a custodial product, check that product's own terms for staking and withdrawal.

Flow is still a live network, but its activity depends on which apps are in use at a given time. Top Shot remains one of the best-known products on the chain, while other Flow applications have grown and shrunk over time. A guide cannot give a reliable snapshot of current usage, so the best approach is to check live sources.

To assess the chain's health, look at a few indicators:

• Active accounts and transaction counts on a block explorer, tracked over weeks.
• Value locked and fees by chain on DefiLlama, which aggregates data across many networks.
• Validator count and distribution on Flow's own network dashboards.
• Release notes and governance activity from the Flow team.

If you are considering building on Flow, read the developer documentation for the current tooling. If you are a collector, follow Top Shot's official announcements. Treat second-hand summaries, including older articles, as starting points rather than final answers.

Flow is not Ethereum, so moving assets to or from it requires a bridge or an exchange withdrawal that supports Flow. Bridges fall into a few broad types, and each has different trust assumptions. The table below gives a general comparison.

Type	How it works	Main consideration
Canonical or native bridge	Run by the chain team and tied to the official network	Usually the most trusted route, but check it is the current official bridge
Third-party bridge	Run by a separate team with its own contracts	Depends on that team's security and liquidity
Messaging protocol	Passes messages between chains for apps to use	Developers must integrate it correctly
Exchange withdrawal	Moves funds through a centralised platform	You depend on the platform's policies and availability

Across and LayerZero are examples of bridge and messaging protocols that operate across many chains. Before using any bridge, confirm that it lists Flow as a supported network, check the contract addresses on the project's official site, and send a small test amount first.

Most losses in NFT and token activity come from phishing, fake sites and granted permissions, not from the chain itself. Defensive habits matter more than any single tool.

Practical checks for Flow users:

• Never share your seed phrase or recovery details with anyone, including people claiming to be support staff.
• Type or bookmark official Flow and Top Shot addresses instead of following links from messages or ads.
• Read every signing request. If you do not understand what it does, cancel it.
• Review connected apps periodically and revoke access you no longer need.
• Keep only the funds you need in hot wallets, and store larger holdings in a wallet you use rarely.

For developers, audit contracts before mainnet deployment, use multi-key account setups for admin actions, and document how keys are rotated. For anyone using a third-party app, check whether it discloses its audits and where its code is published.

If something goes wrong, act quickly. Revoke any permissions you granted, move remaining assets to a new wallet, and report the incident through the official support channel of the affected app.