XMTP
Open messaging protocol for encrypted chats between wallets, apps and agents, used by Base App, World App and Convos.
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XMTP key facts
| Category | Web3 messaging |
|---|---|
| Platforms | API, SDK |
| Fees | Paid by apps in USDC; estimated $5 per 100,000 messages |
| Open source | Yes, public repositories on GitHub |
What is XMTP?
XMTP is an open messaging protocol for encrypted direct and group chats between wallets, people and AI agents. Apps such as Convos, World App and Base App build on it through SDKs for browser, Node, React Native, iOS and Android. Apps pay network fees in USDC, estimated at $5 per 100,000 messages.
How XMTP works
XMTP runs on two layers.
The XMTP Broadcast Network is an off-chain set of nodes that routes and stores encrypted messages. The XMTP App Chain is a dedicated blockchain that records identities, contacts and group permissions. Encryption follows the IETF Messaging Layer Security standard with the ciphersuite MLS_128_HPKEX25519_CHACHA20POLY1305_SHA256_Ed25519, which gives forward secrecy and post-compromise security. Welcome messages, which carry group secrets, add XWING, a hybrid post-quantum key encapsulation built on ML-KEM.
Each user has an inbox ID linked to one or more identities and installations. Any identity that can produce a verifiable signature, such as a wallet or passkey, can message. Network-level consent marks each contact as allowed, unknown or denied, so apps can sort likely spam into a separate tab. Per the docs, nodes see only the timing and size of encrypted payloads.
How to start with XMTP
- End users do not sign up with XMTP itself.
- You pick an app built on it, such as Convos, World App or Base App, and start chatting there.
- Developers choose the Browser, Node, React Native, Android or iOS SDK, create a signer (an existing wallet login works, or the app generates a key pair per user), create a client, and check whether a contact is reachable with canMessage. xmtp.chat is the official web app for testing, and a local XMTP node can be run for development.
XMTP fees and limits
- The docs estimate about $5 per 100,000 messages, assuming 1 KB messages kept for 90 days and a 95/5 split between messaging and gas.
Apps and agents pay network fees in USDC, not end users. Each message carries a base fee, a storage fee per byte-day and a congestion fee that applies only under heavy load. Admin actions on the App Chain, such as adding group members, cost gas. Attachments sent on-network are capped at 1 MB. Messaging fees go to node operators and gas fees to the App Chain.
Risks to know before using XMTP
- Messages are tied to the keys of the identity that received them.
- The security FAQ says a user who loses wallet access must start new conversations, and messages sent to the old wallet cannot be decrypted.
- Node operators can observe query patterns per IP address unless the client uses a proxy.
- XMTP hides who sent a group invitation but not who received it, so an observer can count invitations.
- Fee rates are set by protocol governance and can rise if network volume drops.
XMTP alternatives
Other projects people compare with XMTP.
Messaging app from XMTP Labs for encrypted chats with people and AI agents on the XMTP network.
Wallet-to-wallet notifications and chat protocol, formerly EPNS, whose team now builds Push Chain.
Private messenger with no phone number, onion-routed messages and a node network paid in the SESH token.
Group chat app and open protocol on Base with paid memberships, tips and encrypted messages.
Where XMTP ranks on DappAtlas
Listed next to XMTP
- Status Crypto wallet
XMTP pros and cons
- Quantum-resistant, end-to-end encrypted messages
- SDKs for browser, Node, React Native, iOS and Android
- Node software and core library public on GitHub under the MIT license
- A protocol, not an app: end users need Convos or another client
- Apps pay network fees in USDC, about $5 per 100,000 messages
- Fee figure is an estimate, not a fixed price
XMTP FAQ
What is XMTP?
XMTP is an open messaging protocol for encrypted direct and group chats between wallets, people and AI agents. Apps such as Convos, World App and Base App build on it through SDKs for browser, Node, React Native, iOS and Android. Apps pay network fees in USDC, estimated at $5 per 100,000 messages.
How much does XMTP cost?
Paid by apps in USDC; estimated $5 per 100,000 messages, according to XMTP’s own page (checked Sep 26, 2026).
Sources
How this page works
Sources: XMTP: official site, XMTP Docs: Calculate fees, XMTP: GitHub organization. Data as of Sep 26, 2026.
Not affiliated with any project listed. Educational content, not financial advice.