I'm developing a new multi-coin wallet. Which token's blockchain has the best and most well-documented SDK for mobile development?

If your priority is the best-documented, mobile-friendly SDK for building an actual multi-coin wallet, I’d pick Stellar (XLM) for the quality of the mobile wallet SDK itself—but Ethereum/EVM is the better choice if you mean the broadest ecosystem and number of tokens.

My ranking for mobile wallet development

Why Stellar stands out

Stellar currently has something unusually close to what you're asking for: official wallet-oriented documentation and SDKs, rather than merely a generic blockchain client library.

Its Wallet SDK documentation explicitly covers wallet creation, key handling, transaction signing, balances, and network queries. The current wallet tutorial is available in TypeScript, Kotlin, Flutter, and Swift.

Even better for a multi-coin wallet architecture, Stellar's SDK ecosystem includes iOS, Kotlin Multiplatform, Flutter, JavaScript, Java, Go, Rust, and other SDKs. The Kotlin Multiplatform SDK targets Android and iOS from a shared Kotlin codebase, which is particularly attractive if you're trying to minimize duplicated wallet logic.

But there's an important distinction

If by "multi-coin wallet" you mean something like:

BTC + ETH + USDC + USDT + hundreds of ERC-20s + SOL + other chains then I would not make Stellar your foundation.

I'd build around EVM/Ethereum first. Ethereum's ecosystem has a huge selection of wallet, signing, RPC, account-abstraction, and mobile integration libraries; ethereum.org currently catalogs dozens of app-integration resources, including Android libraries such as web3j.

In that architecture, Ethereum isn't really "one coin"—an EVM implementation gives you access to ETH plus enormous numbers of ERC-20 tokens and multiple EVM-compatible networks.

Where Solana fits

Solana deserves special mention because its mobile tooling is unusually wallet-oriented. Its Mobile Wallet Adapter supports Kotlin, React Native, Flutter, Unity, and Unreal, and Solana maintains dedicated mobile documentation and sample applications.

However, there's a current caveat: Mobile Wallet Adapter is Android-only at present; iOS isn't supported. Solana Mobile Docs That makes Stellar more compelling if you want a genuinely cross-platform native wallet.

My recommendation

For a new wallet, I'd use this strategy:

Core wallet architecture: EVM + Bitcoin + Solana + Stellar, with each chain isolated behind a common interface such as:

Wallet
 ├── BitcoinAdapter
 ├── EVMAdapter
 ├── SolanaAdapter
 └── StellarAdapter

Each adapter:
 ├── generate/import keys
 ├── derive addresses
 ├── get balances
 ├── build transaction
 ├── estimate fees
 ├── sign transaction
 └── broadcast transaction

If you're choosing one blockchain specifically to prototype the wallet architecture, though, Stellar is probably the nicest place to start because the SDK and documentation map so directly onto wallet functionality. Its current documentation even includes wallet-specific material around custody models and passkey/contract-account approaches.

If you tell me whether you're building the wallet in Swift/Kotlin, React Native, Flutter, or a cross-platform C++/Rust core, I can recommend the specific SDK stack and architecture I'd use in 2026.

If you are developing a multi-coin wallet, the single best piece of advice is do not use individual native blockchain SDKs for key management and transaction signing across 10+ different chains. Doing so forces you to manage mismatched cryptography libraries, disparate address derivation paths (BIP44/BIP32 variations), and heavily fragmented documentation.

Instead, the industry standard for multi-chain mobile wallets is a unified cryptographic core library paired with lightweight RPC/Data APIs.

Phase 1: The Best Core SDK for Multi-Coin Key Management

• • What it is: An open-source, cross-platform mobile library written in C++ with native, idiomatic bindings for Swift (iOS) and Kotlin/Java (Android) , plus support for Rust and Kotlin Multiplatform.
  • Why it's the best: It supports over 130 blockchains (Bitcoin, Ethereum/EVMs, Solana, Cosmos, Ripple, TON, etc.) under a single unified API. It handles key generation, mnemonic phrase validation (BIP39), address derivation, and raw transaction signing locally on the device without forcing you to learn the unique cryptographic quirks of every individual chain.

Phase 2: Chain-Specific Standouts (If you need deep native toolkits)

If you are looking at specific ecosystems that go beyond standard signing and provide elite, purpose-built mobile tooling:

• Solana (via Solana Mobile Stack / MWA)
  • Why it stands out: Solana has arguably the most aggressive and well-documented mobile-first ecosystem. Through the Mobile Wallet Adapter (MWA) protocol, Android and iOS apps can communicate seamlessly for signing, and it integrates tightly with hardware-backed secure enclaves like Solana's Seed Vault. If mobile user experience and deep OS-level signing integration are your primary focus, Solana's dedicated mobile docs are exceptional.
• Ethereum & EVM Chains (via Ethers.js / Viem)
  • Why it stands out: While not strictly "mobile-native" out of the box, EVM tooling is the most mature in existence. You can easily wrap TypeScript/JS solutions via React Native or use native ports. Because 90% of layer-2s (Base, Arbitrum, Optimism) are EVM-compatible, writing or integrating an EVM signing layer gives you massive coverage with endless StackOverflow and documentation trails.

Phase 3: The Data & RPC Layer (You can't build a wallet with just an SDK)

An SDK signs transactions, but your wallet app still needs to display balances, token metadata, and history. Pair your core signing SDK with unified RPC and data providers rather than running individual nodes:

• Chainstack or Alchemy for multi-chain RPC node infrastructure.

If you want to map out the architecture, tell me:

• Are you building native (Swift/Kotlin ) or cross-platform (React Native / Flutter)?
• What is your target launch lineup of blockchains?

I can help you structure your key management flow and dependency tree.

If you're building a multi-coin mobile wallet, I’d pick Ethereum/EVM as the primary ecosystem—not because Ethereum itself is necessarily the technically simplest chain, but because the EVM has the strongest combination of SDK maturity, mobile tooling, documentation, wallet interoperability, and multi-chain coverage.

My ranking

Why EVM is my first choice

The important distinction is Ethereum vs. EVM. If you're making a multi-coin wallet, you don't want an SDK that only makes Ethereum easy—you want infrastructure that lets you add Ethereum, Polygon, Arbitrum, Base, Optimism, BNB Chain, Avalanche, etc. without redesigning your wallet architecture.

The current developer ecosystem is exceptionally mature. For example, Coinbase's CDP provides wallet infrastructure for EVM and Solana, including a React Native SDK supporting iOS and Android.

WalletConnect is another major advantage: its Wallet SDK explicitly supports Android, iOS, React Native and Flutter, while its broader ecosystem supports EVM, Solana, Bitcoin and other networks.

That means you can build around established standards rather than implementing chain-specific connection and signing mechanisms yourself.

Solana is the strongest alternative

If your product is going to be Solana-heavy, I'd seriously consider making Solana your primary chain.

Solana Mobile has unusually good first-party mobile tooling. Its current stack supports React Native and Kotlin, with additional community SDKs for Flutter, Unity and Unreal.

It also has Mobile Wallet Adapter tooling for React Native and Kotlin, although an important caveat is that MWA currently has full Android support but no iOS support.

So for a wallet targeting both iOS and Android, I'd give EVM the edge.

Stellar is surprisingly compelling for a payments wallet

If by "multi-coin wallet" you primarily mean stablecoins, remittances, and payments, rather than DeFi/NFTs, Stellar deserves serious consideration.

Its current wallet documentation provides SDK paths for TypeScript, Kotlin, Flutter and Swift, and Stellar has both iOS and Kotlin Multiplatform SDKs.

Stellar's Wallet SDK also specifically targets wallet creation, transaction signing, balance queries, custody models, and on/off-ramps.

That's arguably a cleaner wallet-development experience than EVM if you only care about payments.

What I'd use for your architecture

For a genuinely multi-chain wallet, I'd build the abstraction layer roughly like:

                    Mobile Wallet
                         │
             ┌───────────┴───────────┐
             │   Chain abstraction    │
             └───────────┬───────────┘
                         │
       ┌─────────────────┼─────────────────┐
       │                 │                 │
     EVM              Solana           Bitcoin
       │                 │                 │
 ethers/viem       Solana SDK         BTC SDK
       │                 │                 │
 Ethereum          Solana             Bitcoin
 Base              ...                ...
 Polygon
 Arbitrum
 Optimism
 BNB
 Avalanche

I'd make EVM the first implementation, then add Solana and Bitcoin behind the same internal interfaces for:

• key generation/import
• address derivation
• balance retrieval
• transaction construction
• transaction signing
• transaction broadcasting
• fee estimation
• token metadata
• transaction history

One architectural warning: don't make your abstraction too Ethereum-centric. Account models, transaction formats, fee models, address formats, and token standards differ substantially between EVM, Solana and Bitcoin. Your interface should abstract wallet capabilities, not pretend every chain works like Ethereum.

Bottom line: EVM/Ethereum = best overall choice for a multi-coin mobile wallet. Solana = best alternative if Solana is strategically important. Stellar = potentially best if the wallet is primarily payments/stablecoins.

If you tell me whether you're using React Native, Flutter, Swift/Kotlin, or native iOS/Android, I can narrow this down to the specific SDK stack I'd use and compare the leading libraries (including key management and transaction signing).

When developing a multi-coin (or multi-chain) mobile wallet, looking for a single token's blockchain with the "best" native mobile SDK can actually be a bit of a trap. Most single-chain native libraries (like Bitcoin's libbitcoin or low-level Rust/C++ bindings) have notoriously fragmented, poorly documented, or painful mobile wrappers.

Instead, the gold standard for mobile development splits into two categories: Solana (for the best purpose-built, native mobile ecosystem framework) and EVM/Ethereum ecosystems (leveraging cross-chain infrastructure SDKs).

1. The Best Native Ecosystem-Specific Mobile SDK: Solana

If you want a blockchain ecosystem that has actively solved the mobile UX and integration nightmare, Solana wins decisively.

• The Tech: They maintain the official Mobile Wallet Adapter (MWA) . On desktop, you have browser extensions; on mobile, communication is fractured. MWA creates a standardized local inter-app communication protocol.
• Framework Support: Excellent out-of-the-box support for Kotlin/Android, React Native, Flutter, Unity, and Unreal Engine.
• Documentation Quality: The Solana Mobile Docs are clean, modern, frequently updated, and feature explicit guides for deep-linking, session management, and hardware-backed key storage (like the Seed Vault).
• The Catch: It is heavily optimized for Solana and SVM-compatible chains, meaning you cannot directly use it as your sole architecture for Bitcoin, EVM, or Cosmos assets.

2. The Best Cross-Chain / Multi-Coin Approach: Aggregator & Infrastructure SDKs

Since you are building a multi-coin wallet, relying on a single chain's native SDK will force you to stitch together 5 to 10 completely different, incompatible cryptographic libraries (secp256k1 for Bitcoin/EVM, ed25619 for Solana/Near, etc.). Modern multi-chain mobile developers bypass individual chain SDKs in favor of unified orchestration layers:

• Reown AppKit (formerly WalletConnect): Offers robust cross-chain mobile kits supporting EVM networks, Solana, and more, handling the deep connection plumbing between mobile dApps and wallets seamlessly.
• Thirdweb SDK / Coinbase Wallet SDK: Highly polished mobile wrappers (especially for React Native and native iOS/Android) that abstract away the raw RPC calls and key management for multi-chain environments.
• Alchemy Account Kit / Turnkey / Web3Auth: If you are leaning toward smart accounts (ERC-4337) or Embedded Wallets with passkey support, these infrastructure providers offer the cleanest mobile documentation available, far surpassing any single layer-1 blockchain's native mobile documentation.

To help narrow down the ideal stack for your architecture, tell me:

• Are you planning to build fully self-custodial (local seed phrase on device) or embedded/MPC-based?
• Which specific mobile framework are you targeting (React Native, Flutter, Swift/Kotlin)?
• What is your initial list of supported blockchains?

When developing a multi-coin mobile wallet, Solana stands out as having the most innovative, cleanly engineered, and well-documented mobile-specific ecosystem thanks to the Solana Mobile Stack (SMS).

However, looking at the broader landscape for a multi-coin wallet, you have to weigh ecosystem-specific mobile tooling against generalized core libraries.

1. The Gold Standard for Mobile Architecture: Solana

If you are evaluating dedicated mobile-first blockchain architecture, Solana leads the pack.

• Why it's great: Solana Mobile provides the Mobile Wallet Adapter (MWA) , a standardized protocol for securely connecting native and cross-platform mobile apps to wallets (comparable to WalletConnect, but native to the device). They also provide deep documentation for React Native, Kotlin (Android native), Flutter, and Unity.
• The Documentation: The Solana Mobile Documentation is modern, highly targeted at mobile app lifecycles, and actively maintained.
• The Catch: It is heavily optimized for the Solana ecosystem. While it handles key management and signing elegantly, it won't help you derive Bitcoin or EVM addresses.

2. The Multi-Chain Industry Standard: Trust Wallet Core

For a multi-coin wallet, writing or integrating separate native SDKs for Bitcoin, Solana, XRP, and EVM chains from scratch is a massive engineering overhead. Most top-tier multi-chain wallets don’t use a single token's blockchain SDK; instead, they rely on cross-chain core libraries.

• Why use it: Trust Wallet Core is an open-source, cross-platform, modular C++ library that implements low-level wallet logic—including address generation, HD wallet derivation (BIP44/BIP32), signing, and encoding—across dozens of blockchains (Bitcoin, Ethereum, Solana, Cosmos, etc.).
• Mobile Bindings: It provides native bindings for Swift (iOS) and Kotlin/Java (Android), meaning you write unified logic for cryptographic operations rather than wrestling with chain-specific quirks.

3. The EVM / Account Abstraction Ecosystem: Ethereum & L2s

If your wallet focuses heavily on Ethereum and EVM-compatible networks (Polygon, Arbitrum, Base), you won't use a single "Ethereum SDK". Instead, mobile developers rely on infrastructure SDKs that support Account Abstraction (ERC-4337) and embedded signers.

• Top Tools: Ecosystem toolkits like Reown (formerly WalletConnect), Coinbase Wallet SDK , and smart account tools like Alchemy's Pimlico or ZeroDev provide the cleanest documentation for EVM mobile connectivity.

Recommendation for a Multi-Coin Wallet Strategy

1. For Cryptographic Primitives & Address Derivation: Do not reinvent the wheel or rely on fragmented docs. Start with Trust Wallet Core to handle the multi-chain key derivation, signing, and serialization layer in native Swift/Kotlin.
2. For Chain-Specific RPC and Advanced Mobile UX: If you want to showcase elite mobile-native patterns (like hardware-backed secure enclaves or seamless app-to-app communication), study the architectural patterns in the Solana Mobile Stack Docs —it represents the gold standard of how blockchain documentation should look for mobile engineers.

To help narrow down the architectural approach, could you share:

• Are you building native (Swift/Kotlin) or cross-platform (React Native/Flutter)?
• Which specific list of blockchains/tokens do you plan to support at launch?

If your priority is mobile SDK quality + documentation + ecosystem depth, I’d pick Ethereum/EVM rather than a single non-EVM token.

My ranking

1. Ethereum / EVM — best overall

• Mature, extensively documented RPC and transaction model.
• Excellent TypeScript tooling: viem, ethers, and related libraries.
• Huge ecosystem of wallet, signing, account-abstraction, and mobile integration tooling. Ethereum’s current developer docs explicitly catalog JavaScript APIs, wallet tooling, authentication, and mobile-oriented resources.
• The big advantage for a multi-coin wallet: once you implement EVM support, you can support many chains with essentially the same architecture—Ethereum, Base, Arbitrum, Optimism, Polygon, BNB Chain, Avalanche C-Chain, etc. Ethereum's own documentation notes that the same address can be used across EVM-compatible chains.

2. Solana — best non-EVM choice

• Probably the strongest alternative if you want a modern mobile-first experience.
• Solana provides an official Expo + React Native mobile template using @solana/web3.js and Mobile Wallet Adapter.
• There are also official React Native/Expo templates for embedded wallets, with explicit iOS and Android setup.
• Documentation and developer templates have improved considerably; Solana now maintains dedicated mobile templates alongside its broader SDK ecosystem.

3. Sui — very good SDK/documentation, but smaller ecosystem

• The official docs are unusually comprehensive, covering SDKs, transaction construction, cryptography, asset standards, RPC, and wallet development.
• I'd consider it if you're specifically interested in Move/object-based assets, but I wouldn't choose it as the foundation of a general-purpose multi-coin wallet.

What I'd build

For a serious multi-coin wallet, I'd make the architecture:

Wallet core → BIP-39/32-style key management → secure key storage (Keychain/Keystore/Secure Enclave where appropriate) → chain abstraction → transaction/signing interface

EVM adapter → Ethereum + all major EVM networks → viem/ethers → ERC-20/ERC-721/ERC-1155 → EIP-1559 → EIP-712 → account abstraction where desired

Solana adapter → SOL + SPL tokens → Solana transaction/message signing → Mobile Wallet Adapter

Then add Bitcoin separately, because Bitcoin's transaction/account model is sufficiently different that trying to force it into the EVM/Solana abstraction tends to make the architecture worse.

Bottom line: If you're choosing a blockchain specifically because you want the best developer experience for a mobile multi-coin wallet, choose EVM/Ethereum as your primary SDK target. If you're choosing a single non-EVM chain, I'd give Solana the edge for mobile development today.

If you tell me whether you're using React Native, Flutter, Swift/Kotlin, or a cross-platform framework, I can narrow this down to the actual SDK stack I'd use and compare Ethereum vs Solana vs Bitcoin at the implementation level.

When developing a multi-coin mobile wallet, looking for a single blockchain with the "best" mobile SDK often leads to a clear winner depending on whether you prioritize native mobile hardware integration or EVM ecosystem maturity.

The top contenders for the best-documented and most advanced mobile-first blockchain SDKs are broken down below:

• Solana (SOL) : Winner for Native Mobile Architecture . Solana stands apart because it is the only major layer-1 blockchain that built a comprehensive, hardware-to-app mobile ecosystem from the ground up via the Solana Mobile Stack (SMS).
  • Key Strength : The Mobile Wallet Adapter (MWA) specification solves the hardest part of mobile Web3 development—inter-app communication and secure signing without browser extensions. It includes official, well-maintained SDKs for Kotlin/Android, React Native, Flutter, and Unity, alongside the Seed Vault SDK for hardware-level key isolation.
• Ethereum & EVM (ETH / L2s) : Winner for Ecosystem & Infrastructure Breadth . While Ethereum doesn't have a single native "Solana Mobile-style" hardware layer, the tooling surrounding EVM mobile development is massive, highly modular, and heavily documented.
  • Key Strength : Aggregated provider ecosystems like Thirdweb SDKs or Dynamic offer robust cross-platform mobile support (iOS and Android). Combined with modern Account Abstraction standards (ERC-4337) and embedded wallet kits from providers like Alchemy and Biconomy, managing EVM keys, gas sponsorships, and batch transactions on mobile is exceptionally well-documented.
• Bitcoin (BTC) : The Legacy Benchmark . Bitcoin mobile SDKs (like BDK - Bitcoin Development Kit) are mature and extremely secure, focusing heavily on robust HD wallet derivation (xpub, ypub, zpub ) and PSBT (Partially Signed Bitcoin Transactions) handling. However, they lack the high-level interactive user session features found in newer smart contract chains.

Summary Recommendation

If you are building the wallet client itself, Solana's Mobile Wallet Adapter (MWA) provides the cleanest, most forward-thinking architectural standard for mobile app-to-wallet signing. For supporting the broader multi-coin landscape (hundreds of EVM chains and tokens), pairing that with a versatile EVM provider toolkit is the industry standard path.

To help narrow down your stack, tell me:

• Are you building a non-custodial (self-sovereign seed phrase) or an embedded/MPC custodial wallet?
• Which mobile framework are you planning to use (Native iOS/Android, React Native, or Flutter)?

For a multi-coin wallet, the answer changes depending on whether you mean:

1. Best blockchain SDK for building a wallet app around one chain, or
2. Best foundation for a wallet that supports many chains.

For the second case, I would not pick a single token's blockchain SDK. I would build around a multi-chain wallet core and add chain-specific modules. The strongest options today are:

My recommendation for a new multi-coin wallet

Use Ethereum/EVM as your first-class integration, then add Bitcoin and Solana.

Reasons:

• EVM gives you the largest addressable asset universe: ETH, ERC-20 tokens, stablecoins, L2s, and many chains use nearly identical signing and transaction models.
• Libraries such as ethers/web3 tooling have years of documentation and community examples.
• You can reuse much of your transaction, signing, and token-management architecture across chains.

For the actual wallet engine, I would strongly consider:

1. Wallet core layer

Use a library like Trust Wallet's Wallet Core. It is specifically designed as a cross-platform mobile wallet library, with Swift and Kotlin interfaces and support for many chains including Bitcoin, Ethereum, Cosmos, and Solana.

Architecture:

Mobile UI (Swift/Kotlin/React Native/Flutter)
             |
        Wallet Core
             |
 ┌───────────┼───────────┐
 Ethereum   Bitcoin    Solana
   |          |          |
 ERC20      UTXO       SPL tokens

2. If you want the easiest developer experience

Pick Solana if you are building a mobile-first crypto app rather than a traditional wallet. There are purpose-built mobile resources, including React Native scaffolding and mobile wallet tooling.

Solana is attractive for:

• fast transactions
• low fees
• mobile payments
• consumer apps

3. If you want maximum chain coverage

Look at the Cosmos ecosystem. Cosmos SDK chains share many concepts and have interoperability through IBC, making it attractive for multi-asset wallets. docs.cosmos.network However, you still need chain-specific handling because each Cosmos chain can customize modules and transaction formats.

---

A practical stack I would choose in 2026

Frontend

• React Native + TypeScript (fast cross-platform iteration)
  or
• Native Swift + Kotlin (best security/control)

Wallet engine

• Trust Wallet Core or equivalent cryptographic core

First chains

1. Ethereum + EVM networks
2. Bitcoin
3. Solana
4. Cosmos/IBC assets

Backend

• RPC abstraction layer (Alchemy, Infura, QuickNode, self-hosted nodes)
• Indexer service for balances/history
• Push notification service for transactions

---

If I had to choose one blockchain ecosystem purely by SDK quality for a mobile wallet, I would pick:

🥇 Ethereum/EVM for the broadest and best-documented development environment
🥈 Solana for the most mobile-native experience
🥉 Cosmos for multi-chain architecture

For a serious multi-coin wallet, though, the winning design is a chain-agnostic wallet core with EVM as the first integration, not a wallet built around only one token.

When developing a new multi-coin wallet, evaluating blockchain SDKs requires looking at native mobile tooling, cryptographic key handling , and documentation quality.

Depending on your architecture, you either need chain-specific mobile deep-linking/adapters or a unified multi-chain core library. The ecosystems with the best and most well-documented mobile developer experiences stand out in distinct ways:

• Solana has the best native mobile-specific hardware and app-linking SDK via the Solana Mobile Stack (SMS). Solana provides first-party documentation and tools for React Native/Expo , native Android (Kotlin), and Flutter, centered around the Mobile Wallet Adapter (MWA) protocol which allows seamless, secure communication between apps and mobile wallets without custom backend plumbing.
• Ethereum & EVM Chains have the most robust overall wallet infrastructure and documentation, though it is fragmented. If you are building an EVM-compatible layer, toolkits like WalletConnect Wallet SDK, Openfort , and modern account abstraction libraries offer extensive cross-platform documentation for Swift, Kotlin, and React Native.
• Multi-Chain Core (Cross-Blockchains) : If your goal is a true multi-coin wallet supporting 50+ disparate blockchains (Bitcoin, EVM, Solana, Cosmos) from a single codebase without maintaining 10 different native libraries, Trust Wallet Core is the industry standard open-source mobile SDK. It handles unified key derivation, HD wallets, and transaction signing across ecosystems with a single compiled C++/Swift/Java wrapper.

The following video explores how interconnected multi-chain architectures work on the interchain level:

Watch this overview to understand how multi-chain ecosystems and wallet interoperability function across different networks:

58s What's the BEST Wallet for Cosmos?3.8K views  · 1 year ago YouTube · CoinGecko

To help narrow down the ideal approach for your project, let me know:

• Are you planning to build natively using React Native/Flutter , or Swift/Kotlin?
• Do you intend to use a unified multi-chain core library like Trust Wallet Core , or integrate individual native SDKs per chain?

If your goal is a multi-coin mobile wallet, I’d choose Ethereum/EVM as the primary ecosystem, with Solana as the strongest alternative if mobile-native tooling is your top criterion.

My ranking

1. Ethereum/EVM — best overall choice

For a wallet, the big advantage isn't Ethereum's native SDK alone; it's the entire EVM tooling ecosystem. Libraries such as viem provide wallet/account, signing, transaction, ABI, and RPC functionality, while WalletConnect/Reown has mature React Native wallet tooling. Viem explicitly supports local private-key/mnemonic accounts as well as WalletConnect-style JSON-RPC accounts.

WalletConnect's current React Native documentation also provides a fairly complete wallet integration path, including initialization, sessions, signing, transaction requests, and EVM methods.

The really important benefit for your project is that one EVM implementation gets you Ethereum plus a huge number of EVM-compatible networks—Base, Arbitrum, Optimism, Polygon, BNB Chain, etc.—rather than implementing a separate wallet architecture for every chain.

2. Solana — arguably the best mobile-native experience

If by "best SDK for mobile" you literally mean the blockchain whose developers have invested most heavily in mobile-specific tooling, I'd give the edge to Solana.

Solana Mobile maintains official SDKs for React Native and Kotlin, alongside its Mobile Wallet Adapter and mobile-specific development guides. It also provides scaffolds, sample apps, recipes, and a dedicated mobile dApp ecosystem.

That's unusually compelling if you're building a wallet that needs to feel native on phones rather than simply adapting web3 libraries to React Native.

What I'd actually build

For a new multi-coin wallet, I'd architect it like this:

Core wallet engine

• BIP-39/BIP-32/SLIP-44 key management
• Secure enclave/Keychain/Keystore integration
• Hardware-backed encryption where available
• Chain-independent account abstraction

Chain adapters

• EVM: Ethereum + L2s + EVM chains
• Solana: SOL + SPL tokens
• Then add Bitcoin, Sui, etc. as independent adapters

Mobile layer

• React Native if you want maximum code sharing
• Native Kotlin/Swift modules for secure key storage and chain-specific cryptography
• WalletConnect/Reown for dApp connectivity
• Chain-specific adapters underneath a common wallet interface

The key architectural decision is not to make Ethereum, Solana, etc. subclasses of one another. Treat each blockchain as a plugin implementing something like:

BlockchainAdapter
├── deriveAccount()
├── getBalance()
├── getTokenBalances()
├── buildTransaction()
├── estimateFee()
├── signTransaction()
├── broadcastTransaction()
└── parseTransaction()

Then your UI doesn't care whether an account is Ethereum, Solana, or Bitcoin.

Bottom line: If you want one ecosystem to build around first, choose Ethereum/EVM because its tooling and network coverage are unmatched. If your differentiator is specifically mobile-first crypto UX, build Solana support early—its official mobile stack is unusually strong.

If you tell me whether you're using React Native, Flutter, Swift/Kotlin, or a cross-platform stack, I can also compare the actual SDKs/libraries I'd use for key generation → signing → RPC → token balances → dApp connection for each chain.