aid: signal url: https://raw.githubusercontent.com/api-evangelist/signal/refs/heads/main/apis.yml apis: - aid: signal:signal-protocol-specifications name: Signal Protocol Specifications tags: - Encryption - Messaging - Cryptography - Security - Protocols humanURL: https://signal.org/docs/ properties: - url: https://signal.org/docs/ type: Documentation description: >- The Signal Protocol Specifications define the core cryptographic protocols that underpin Signal's end-to-end encrypted messaging. These include the X3DH (Extended Triple Diffie-Hellman) key agreement protocol for establishing shared secrets between parties, the Double Ratchet Algorithm for deriving new encryption keys per message, the PQXDH (Post-Quantum Extended Diffie-Hellman) protocol for quantum-resistant key agreement, and XEdDSA for EdDSA-compatible signature schemes. These specifications are published independently so they can be adopted by other projects beyond Signal itself. - aid: signal:signal-libsignal-sdk name: Signal libsignal SDK tags: - SDK - Encryption - Cryptography - Java - Swift - TypeScript - Rust humanURL: https://github.com/signalapp/libsignal properties: - url: https://github.com/signalapp/libsignal type: GitHub - url: https://github.com/signalapp/libsignal type: Documentation description: >- The libsignal SDK provides platform-agnostic APIs used by the official Signal clients and server. It implements the Signal Protocol including the Double Ratchet algorithm, as well as other cryptographic primitives such as AES-GCM encryption and zero-knowledge group functionality. The core implementations are written in Rust, with bindings exposed as Java, Swift, and TypeScript libraries. - aid: signal:signal-server name: Signal Server tags: - Messaging - Server - Backend - Encryption - Open Source humanURL: https://github.com/signalapp/Signal-Server baseURL: https://chat.signal.org properties: - url: https://github.com/signalapp/Signal-Server type: GitHub - url: https://github.com/signalapp/Signal-Server type: Documentation - url: openapi/signal-server-openapi.yml type: OpenAPI - url: asyncapi/signal-server-asyncapi.yml type: AsyncAPI - url: rules/signal-rules.yml type: SpectralRules - url: capabilities/secure-messaging.yaml type: Capabilities - url: json-schema/signal-protocol-entities-schema.json type: JSONSchema - url: json-ld/signal-context.jsonld type: JSONLD - url: vocabulary/signal-vocabulary.yml type: Vocabulary description: >- Signal-Server is the open-source server backend that supports the Signal Private Messenger applications on Android, Desktop, and iOS. Built as a Dropwizard application, it provides REST controllers for account management, message delivery, key distribution, and device provisioning, along with gRPC services and WebSocket endpoints for real-time communication. The server handles user registration, encrypted message routing, push notification delivery, and pre-key bundle management. - aid: signal:signal-android-sdk name: Signal Android SDK tags: - Android - Mobile - Messaging - Encryption - Open Source humanURL: https://github.com/signalapp/Signal-Android properties: - url: https://github.com/signalapp/Signal-Android type: GitHub - url: https://github.com/signalapp/Signal-Android type: Documentation description: >- Signal-Android is the open-source Android client for the Signal encrypted messaging platform. It provides the full messaging experience including end-to-end encrypted text messages, voice calls, video calls, group chats, and media sharing. The application integrates the libsignal protocol library for cryptographic operations and communicates with the Signal Server for message routing and delivery. - aid: signal:signal-ios-sdk name: Signal iOS SDK tags: - iOS - Mobile - Messaging - Encryption - Open Source humanURL: https://github.com/signalapp/Signal-iOS properties: - url: https://github.com/signalapp/Signal-iOS type: GitHub - url: https://github.com/signalapp/Signal-iOS type: Documentation description: >- Signal-iOS is the open-source iOS client for the Signal encrypted messaging platform. It delivers end-to-end encrypted messaging, voice calls, video calls, and group communications on iPhone and iPad devices. The application uses the libsignal protocol library for all cryptographic operations and connects to the Signal Server infrastructure for message delivery and synchronization. - aid: signal:signal-desktop-sdk name: Signal Desktop SDK tags: - Desktop - Electron - Messaging - Encryption - Open Source humanURL: https://github.com/signalapp/Signal-Desktop properties: - url: https://github.com/signalapp/Signal-Desktop type: GitHub - url: https://github.com/signalapp/Signal-Desktop type: Documentation description: >- Signal-Desktop is the open-source desktop client for the Signal encrypted messaging platform, built with Electron and TypeScript. It provides end-to-end encrypted messaging, voice calls, video calls, and group communications on Windows, macOS, and Linux. The desktop client links to an existing Signal mobile account and synchronizes messages across devices. name: Signal tags: - Encryption - Messaging - Security - Cryptography - Open Source - Privacy type: Contract image: https://kinlane-productions.s3.amazonaws.com/apis-json/apis-json-logo.jpg access: 3rd-Party created: '2026-03-20' modified: '2026-05-02' position: Consuming segments: - Messaging - Security - Cryptography description: >- Signal is a privacy-focused messaging platform that provides end-to-end encrypted communication through open-source applications on mobile and desktop. Their developer ecosystem centers around the open-source Signal Protocol, client SDKs, and server infrastructure, enabling developers to study, audit, and integrate secure messaging capabilities. The Signal Protocol is the most widely deployed end-to-end encryption protocol in the world, used by Signal, WhatsApp, Google Messages, and other platforms. common: - type: Website url: https://signal.org/ - type: Documentation url: https://signal.org/docs/ - type: Blog url: https://signal.org/blog/ - type: Support url: https://support.signal.org/ - type: TermsOfService url: https://signal.org/legal/ - type: PrivacyPolicy url: https://signal.org/legal/#privacy-policy - type: GitHub url: https://github.com/signalapp maintainers: - FN: Kin Lane email: kin@apievangelist.com specificationVersion: '0.19'