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Open-Source Databases · ammarahm-ed

react-native-mmkv-storage

react-native-mmkv-storage is a fast, encrypted key-value storage library for React Native built on Tencent's MMKV (used in WeChat) with C++/JSI implementation. It offers 0.0002s read/write performance, multi-instance support, and built-in encryption, positioning itself as a faster alternative to AsyncStorage.

Source: GitHub — github.com/ammarahm-ed/react-native-mmkv-storage
1.8k
GitHub stars
121
Forks
C++
Primary language
MIT
License (OSI-approved)

Key facts

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FieldValue
Repositoryammarahm-ed/react-native-mmkv-storage
Ownerammarahm-ed
Primary languageC++
LicenseMIT — OSI-approved
Stars1.8k
Forks121
Open issues46
Latest releasev12.0.1 (2025-12-04)
Last updated2025-12-04
Sourcehttps://github.com/ammarahm-ed/react-native-mmkv-storage

What react-native-mmkv-storage is

C++ JSI-based wrapper around MMKV with mmap-backed memory synchronization and protobuf encoding. Supports AES CFB-128 encryption (Keychain/Android Keystore), transaction lifecycle hooks, multi-process access, and reactive hooks (useMMKVStorage, useIndex). Requires React Native 0.71.0+.

Quickstart

Get the react-native-mmkv-storage source

Clone the repository and explore it locally.

terminalbash
git clone https://github.com/ammarahm-ed/react-native-mmkv-storage.gitcd react-native-mmkv-storage# follow the project's README for install & configuration

Need it deployed, integrated, or customized instead? DEV.co ships production installs.

Best use cases

High-frequency local state persistence

Apps needing microsecond-level read/write latency for frequently accessed data (user preferences, session state, temporary caches) where AsyncStorage performance becomes a bottleneck.

Sensitive data storage in mobile apps

Mobile applications requiring transparent AES encryption for PII, tokens, or credentials without developer overhead—encryption key auto-managed via platform keychains.

Multi-instance domain separation

Modular apps or those with extensions/widgets needing separate storage instances per logical domain for better performance isolation and cleaner data architecture.

Implementation considerations

  • Requires React Native ≥0.71.0; migrations from older RN versions or AsyncStorage may need careful key translation and testing.
  • Encryption key rotation and backup strategy must be designed upfront; Android Keystore and iOS Keychain have different availability guarantees across device resets.
  • Transaction hooks (beforewrite, afterread, beforedelete) can impact performance if overused; profile custom indexes and lifecycle logic in production scenarios.
  • Multi-process access is supported but concurrent write coordination is caller's responsibility; design update patterns carefully in widget/extension scenarios.
  • Cold start performance depends on total data size in mmap; monitor app launch times as database instances grow.

When to avoid it — and what to weigh

  • Relational data with complex queries — Projects needing SQL joins, aggregations, or complex filtering should use SQLite or a proper database; MMKV is key-value only with basic indexing.
  • Managed dependency or vendor lock-in concerns — Organizations requiring guaranteed long-term vendor support, SLAs, or reluctant to adopt community-maintained open-source should evaluate commercial database providers.
  • Large dataset storage (>50MB) — MMKV trades off query complexity for speed via in-memory mmap; very large datasets may cause memory pressure or slow startup on resource-constrained devices.
  • Cross-platform (desktop/web) requirement — Library is React Native–only (iOS/Android); projects needing unified storage across web and mobile require alternative solutions.

License & commercial use

MIT License. Permissive OSI-approved license allowing commercial use, modification, and distribution with attribution. No royalties, no restrictions on proprietary applications.

MIT license permits unrestricted commercial use in closed-source products. No commercial support, SLA, or indemnification provided by maintainers. Evaluate fork risk and internal maintenance capacity for mission-critical deployments.

DEV.co evaluation signals

Editorial assessment — not user reviews. Directional, with an explicit confidence level.

SignalAssessment
MaintenanceActive
DocumentationAdequate
License clarityClear
Deployment complexityLow
DEV.co fitGood
Assessment confidenceHigh
Security considerations

Library uses AES CFB-128 encryption stored in platform keychains (iOS Keychain, Android Keystore API 23+). Encryption key is auto-generated and managed by the library; no audit results, penetration test findings, or CVE history disclosed in available data. Requires Android API 23+ for keystore. Consider that mmap-backed storage may be subject to memory-dump attacks on rooted/jailbroken devices; assess threat model accordingly.

Alternatives to consider

AsyncStorage (React Native built-in)

Slower (~0.01s per op) but stable, no native build required, suitable for low-frequency reads/writes.

SQLite (via react-native-sqlite-storage)

Full relational database with complex querying, indexing, and transactions; overkill for key-value but necessary if relational schema required.

Realm (via realm)

Object database with offline sync, cross-platform (includes web), managed cloud sync option; higher overhead but richer query semantics.

Software development agency

Build on react-native-mmkv-storage with DEV.co software developers

Evaluate react-native-mmkv-storage for your React Native app. Confirm encryption, key management, and migration strategy with your engineering team. Consider community support risk and internal maintenance capacity.

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react-native-mmkv-storage FAQ

Is encryption mandatory?
No. Encryption is opt-in via .withEncryption() during initialization. Unencrypted instances are faster and have no keystore dependency.
Can I migrate from AsyncStorage?
Yes, but manual. Read keys from AsyncStorage, write to MMKV instance, verify, then remove old keys. No built-in migration tool provided.
Does MMKV support cloud sync or replication?
No. It is local-only. Cloud/cross-device sync must be implemented separately (e.g., custom REST sync, Firebase Realtime DB, or similar).
What happens if the encryption key is lost (e.g., factory reset)?
Encrypted MMKV data becomes unrecoverable if the keychain/keystore entry is wiped. Plan for user account re-authentication or graceful degradation.

Software developers & web developers for hire

DEV.co helps companies turn open-source tools like react-native-mmkv-storage into production software. Our software development services cover the full lifecycle — architecture, web development, integration, and maintenance — delivered by software developers and web developers who ship. Engage our software development agency to implement or customize it for your open-source databases stack.

Need Production-Ready Mobile Storage?

Evaluate react-native-mmkv-storage for your React Native app. Confirm encryption, key management, and migration strategy with your engineering team. Consider community support risk and internal maintenance capacity.