# My First On-Chain Experience on Base

By [Mario](https://paragraph.com/@tortmario) · 2025-12-19

base mini app development, base l2 ethereum, farcaster mini app, on-chain off-chain architecture, next.js web3 application, erc-721 smart contract base, web3 mini app architecture, ethereum l2 rpc performance, smart contract deployment base

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The Wall Base: Technical Architecture of a Social Mini App on Base App
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On **December 18, 2025**, Base officially launched its **Mini App SDK**, but I got access a bit earlier during the beta phase.  
That immediately raised a question for me:

> _Can I build a mini app where_ **_every user action leaves an on-chain footprint_**_, while still keeping a fast, Web2-like UX?_

That’s how [**The Wall Base**](https://basewall.vercel.app/) was born — a social mini app running inside **Farcaster / Base App**.

**What is The Wall Base?**
--------------------------

[**The Wall Base**](https://basewall.vercel.app/) consists of:

*   a social feed of posts;
    
*   NFT minting for each post;
    
*   a marketplace tovery action;
    
*   an **off-chain raffle** that pays the pool to a random NFT owner.
    

This is my **first experience with Base SDK and on-chain development**, and in this article I share what I learned and what I struggled with.

If you have suggestions on how something could be done better or simpler — feel free to leave a comment. I’d really appreciate feedback.

**Architecture Overview**
-------------------------

**Tech Stack**
--------------

*   **Next.js 14 (App Router)** — server components, layouts
    
*   **TypeScript**
    
*   **Tailwind CSS**
    
*   **Zustand** for local state
    
*   **viem** and **wagmi** for on-chain interactions
    

**App Router inside Base App: Important Constraints**
-----------------------------------------------------

Inside Base App, you **cannot** rely on standard web assumptions:

*   full SSR is not available (part of the environment is restricted);
    
*   unstable `fetch` calls (some origins are blocked);
    
*   system navigation (`window.location`) is not allowed — everything must stay inside the mini-app sandbox.
    

Base App is very friendly to **Vercel**, so deployment was straightforward.

Critical rules:

*   use
    

    export const dynamic = "force-dynamic";

*   when UI must update on every request;
    
*   avoid `window`\-dependent logic in server components;
    
*   keep heavy API logic inside `/api/*` routes.
    

**Backend Layer: API, KV, and Off-Chain Data**
----------------------------------------------

Posts live **off-chain** — otherwise the mini app would be painfully slow when loading the feed.

**Storage**
-----------

*   **Vercel KV** — main production storage
    
*   local JSON file — development mode
    

**Data Placement**
------------------

DataWhereWhyPostsKVFast, almost freeReactionsKVLow trafficWinners historyKVNo need to be on-chainPost ↔ NFT mappingForumNFT contractMost valuable data

**Smart Contracts: ForumNFT and Marketplace on Base Mainnet**
-------------------------------------------------------------

All production contracts of **The Wall Base** are deployed on **Base mainnet**.

**What is Base?**
-----------------

**Base** is an Ethereum Layer 2 rollup developed by Coinbase, built on the **OP Stack**.

This gives us:

*   full EVM compatibility (Solidity, Hardhat, Foundry);
    
*   significantly lower fees than Ethereum mainnet;
    
*   fast transaction finality;
    
*   native integration with Coinbase and Base App.
    

For mini apps, Base is almost ideal: cheap gas, fast UX, Ethereum-level security.

**Why Development Was Done on Base Sepolia**
--------------------------------------------

Even though production runs on **Base mainnet**, all development and testing happened on **Base Sepolia**, the Base testnet.

Reasons are straightforward:

*   contract deployment costs **real ETH**;
    
*   every logic mistake costs money;
    
*   testnet behavior mirrors mainnet almost exactly.
    

Deploying a simple ERC-721 contract on Base mainnet typically costs **$5–10**, depending on complexity and network load.

So all logic — from minting to prize pool — was fully tested on testnet first.

**How Contract Deployment Actually Works**
------------------------------------------

This is something beginners often misunderstand.

A smart contract is **not deployed from an IDE**.

Deployment flow:

*   written locally (Solidity);
    
*   compiled locally (Hardhat);
    
*   sent to the network via an **EVM wallet**.
    

You need:

*   a wallet private key;
    
*   a network RPC endpoint;
    
*   ETH balance (testnet or mainnet).
    

Deployment is just a regular transaction that sends contract bytecode to the network.

    npx hardhat run scripts/deploy.js --network base

**Test ETH for Base Sepolia**
-----------------------------

To use Base Sepolia, you need test ETH.

I used the Alchemy faucet:  
[https://www.alchemy.com/faucets/base-sepolia](https://www.alchemy.com/faucets/base-sepolia)

Important caveat: it usually works **only for wallets with mainnet activity**.

I couldn’t find a faucet that reliably sends ETH to brand-new wallets.  
An alternative is bridging ETH from Ethereum testnet to Base Sepolia using testnet bridges — these exist, but for beginners it’s another quest.

If you’re stuck — ask in the comments, I’ll try to point to currently working bridges.

**On-Chain vs Off-Chain Separation**
------------------------------------

The project clearly separates two layers.

**On-chain**
------------

*   smart contracts (ForumNFT, Marketplace);
    
*   funds custody;
    
*   NFT ownership;
    
*   prize pool.
    

**Off-chain**
-------------

*   frontend (Next.js);
    
*   post storage;
    
*   winner selection;
    
*   UI/UX;
    
*   RPC interaction.
    

Contracts are deployed independently from the frontend and communicate via RPC.

**Moving from Base Sepolia to Base Mainnet**
--------------------------------------------

Once contracts were fully tested on Base Sepolia, moving to mainnet was simple:

1.  Deploy contracts to Base mainnet
    
2.  Get new contract addresses
    
3.  Update frontend configuration
    

    # beforeNEXT_PUBLIC_BASE_RPC_URL=https://sepolia.base.orgNEXT_PUBLIC_NFT_CONTRACT_ADDRESS=0xTestAddress

    # afterNEXT_PUBLIC_BASE_RPC_URL=https://mainnet.base.orgNEXT_PUBLIC_NFT_CONTRACT_ADDRESS=0xMainnetAddress

Thanks to EVM compatibility, contract behavior is identical — although the migration still had pitfalls, which I’ll describe below.

**ForumNFT: Custom ERC-721**
----------------------------

Key features:

*   minting at a fixed price;
    
*   50% → `rewardPool`, 50% → `ownerBalance`;
    
*   mappings between posts and tokens;
    
*   service values:
    
*   `nextTokenId`
    
*   `MIN_REWARD_RESERVE = 0.0001 ether`
    

**adminSetNextTokenId**
-----------------------

    function adminSetNextTokenId(uint256 value)    external    onlyOwner

Why it exists:

During beta testing, mini apps generate many temporary posts.  
I periodically burned the entire collection and reset state — which required resetting `nextTokenId`.

⚠ If called without a full burn → token ID collisions are possible.

**Marketplace**
---------------

*   NFT listings with price
    
*   purchases with commission
    
*   part of the fee goes to `rewardPool`
    
*   all trades are standard ETH transactions (cheap on Base)
    

**Prize Pool Logic**
--------------------

The pool is funded by:

    minting (50%)+ marketplace fees+ ownerBalance (manual top-ups)

A **0.0001 ETH reserve** is always preserved — otherwise the pool could hit zero and break ETH/USD price queries.

**Why the Raffle Is Off-Chain**
-------------------------------

Base Mini Apps:

*   don’t support on-chain randomness;
    
*   have no built-in VRF;
    
*   can’t force users to wait for Chainlink callbacks.
    

Implementation:

*   `/api/reward/draw` selects a random post (PRNG + filters);
    
*   sends `payPrize(winner, tokenId, amount)` transaction;
    
*   stores winner history in KV.
    

**Farcaster Mini App SDK Integration**
--------------------------------------

Used methods:

*   `sdk.actions.openUrl()` — open user profil
    
*   `sdk.actions.openPage()` — internal navigation
    
*   `sdk.ready()` — required before rendering UI
    

Constraints:

*   no `window.location` navigation;
    
*   links must be whitelisted in the manifest;
    
*   only `base.app` and `farcaster.xyz` links are clickable.
    

**RPC: Why Nothing Worked on Mainnet at First**
-----------------------------------------------

This was one of the most painful issues.

Marketplace NFTs wouldn’t load, prize pool wouldn’t update.  
The root cause was **public RPC throughput limits**.

**What I tried initially**
--------------------------

*   `https://mainnet.base.org`
    
*   `https://developer-access-mainnet.base.org`
    
*   shared Infura / Alchemy endpoints
    

Problems:

*   4–7s timeouts on reads;
    
*   unstable viem/wagmi responses;
    
*   random `execution reverted`;
    
*   `eth_call` worked while `eth_sendTransaction` failed;
    
*   additional rate limits inside Base App WebView.
    

For mini apps, this is fatal.

**Solution: Private RPC from Coinbase Developer Platform**
----------------------------------------------------------

Normally private RPCs are paid, but Coinbase Developer Platform provided them **for free**, plus:

*   **$500 in USDC credits**
    
*   gas fee rebates for app users
    

Private endpoint:

    https://base-mainnet.g.alchemy.com/v2/<private_key>

Used as:

    NEXT_PUBLIC_BASE_RPC_URL=<private_rpc>

Results:

*   response time dropped to 90–120 ms;
    
*   no missed `eth_call`;
    
*   stable mobile behavior;
    
*   marketplace loaded consistently;
    
*   prize pool updates became reliable.
    

Mini apps are extremely latency-sensitive — the difference was dramatic.

**Admin Panel: Technical Details**
----------------------------------

Admin features:

*   view `ownerBalance`;
    
*   manage fees;
    
*   manual prize draw;
    
*   reset token counter;
    
*   hide posts (moderation);
    
*   mark featured posts (highlight key ecosystem users).
    

Security:

*   frontend checks `ADMIN_ADDRESS`;
    
*   real protection is on-chain via `onlyOwner`.
    

**Mini App Manifest and Assets**
--------------------------------

File: `public/.well-known/farcaster.json`

    {  "name": "The Wall Base",  "description": "Farcaster mini-app: NFT posts, marketplace, prize pool",  "iconUrl": "/200_00000.png",  "splashUrl": "/1024_00000.png",  "developer": "base.app/<username>"}

For development, `noindex=true` is required — otherwise the manifest gets cached.

**Common Issues and Fixes**
---------------------------

**1\. wagmi + mini app environment**
------------------------------------

You cannot rely on `window.ethereum`. Use the Base App connector.

**2\. BigInt in React state**
-----------------------------

BigInt inside JSON can crash WebView. Serialize to string.

**3\. ETH → USD rate**
----------------------

CoinMarketCap rate-limits aggressively. Cache for ~30 minutes.

**Deployment**
--------------

**Contracts (Hardhat)**
-----------------------

    npx hardhat run scripts/deploy.js --network basenpx hardhat verify --network base <ForumNFT>

**Frontend (Vercel)**
---------------------

*   root: `/miniapp`
    
*   build: `npm run build`
    
*   env: private RPC + contract addresses
    

**Conclusion**
--------------

What started as an experiment became a real product:

*   a social network — where every post is an NFT;
    
*   a marketplace — embedded directly into a mini app;
    
*   a prize pool — fully on-chain;
    
*   Base App integration — feels like a native mobile app.
    

**Base Mini Apps open a huge opportunity for hybrid dApps.**

If you’re interested in building on Base App, check the links below.

**Links**
---------

*   **Base App** (invite):  
    [https://base.app/invite/mynameisthe/X5W2YTPB](https://base.app/invite/mynameisthe/X5W2YTPB)
    
*   **Base Docs**:  
    [https://docs.base.org/get-started/base](https://docs.base.org/get-started/base)
    
*   **The Wall Base**:  
    [https://basewall.vercel.app/](https://basewall.vercel.app/)
    

[**My baseapp account**](https://base.app/profile/mynameisthe.base.eth) — a fundamental analysis of coins and earnings on AirDrops. I buy cryptocurrency on [**Bybit**](https://partner.bybit.com/b/60057)

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*Originally published on [Mario](https://paragraph.com/@tortmario/my-first-on-chain-experience-on-base)*