X opened its encrypted direct-messaging system to outside developers on July 30th, launching an API and software development kit for building customer-support bots, automated services and AI agents inside X Chat.
In a two-post announcement on X, X said pay-per-use accounts can process up to 500 messages per day at no charge for a limited time. X did not specify an end date for the promotion. The allowance does not appear on X's public pricing page, which lists received chat events at $0.01 apiece and sent chat events as unbilled.
The release adds a programmable inbox to a network historically built around public posts. It also gives X's product organization, led by Nikita Bier (@nikitabier), another route for turning private messaging into a distribution channel. Before joining X, Bier founded the social apps tbh and Gas, which were acquired by Facebook and Discord, respectively, according to his Lightspeed profile.
What developers get
The X Chat API lets applications send and receive encrypted direct messages. According to X's documentation, message bodies are encrypted on the client before X routes the ciphertext. Messages are also signed, allowing recipients to verify the sender.
X released its Chat XDK on GitHub under an MIT license. The kit provides bindings for Python, JavaScript and WebAssembly, Rust, Go, .NET and the Java Virtual Machine. All six use a common Rust core for key management, encryption, message signing and the wire protocol.
That common implementation reduces the chance that developers working in different languages will construct incompatible cryptographic flows. The kit handles identity and signing keys, conversation-key exchanges, encryption and decryption, signature verification and optional passcode-protected key backup.
X's getting-started documentation includes runnable examples for each supported language. Developers need an X developer account, an application configured for OAuth 2.0 and user authorization for direct-message and account-reading scopes. Each user must authorize X Chat activity tied to that account.
The SDK supports two approaches to private-key storage. Server applications and bots can export an opaque key blob for protected storage. Client applications can use passcode-protected backup to recover keys on another device. X warns that losing the passcode or an unprotected key blob can prevent users from decrypting earlier messages.
The pricing favors reactive bots
X's stated launch use cases, customer support and AI agents, fit the economics and policy constraints around the API. Under X's pay-per-use pricing, a received chat event costs $0.01, while sending a chat message is not billed. Five hundred received events would therefore cost $5 outside any promotional allowance, although the announcement does not define whether its 500-message limit counts sent messages, received messages or both.
X also requires automated accounts to wait for a user to initiate a direct-message interaction, according to its developer guidelines. That rule blocks the Chat API from becoming a sanctioned channel for unsolicited inbox campaigns. It instead favors support systems and assistants that respond after a customer opens the conversation.
The cost model places the charge on receiving demand rather than producing replies. A support bot can answer several times without incurring a listed per-send fee, but every new inbound event adds cost. Developers still have to account for model inference, storage and their own infrastructure when an AI system sits behind the X inbox.
X's broader developer pitch now ties the social network directly to xAI's model business. The pricing page offers developers xAI API credits worth up to 20% of their X API credit purchases once spending reaches the top published reward tier. The Chat API creates a direct use for that pairing: an application can receive a message through X, send it to an AI model and return the generated response to the same encrypted conversation.
The technical release is substantial enough for developers to test that loop without building cryptography separately for each language. X still controls the account authorization, routing, billing and policy layer. That makes the Chat API a new development surface inside X, rather than an independent messaging protocol developers can carry elsewhere.