Offchain Calls

TODO: Write content for this page.

Call canister functions from outside the IC using agent libraries. Explain the IC agent concept: a client-side library that constructs ingress messages, signs them, and sends them to boundary nodes. Cover the agent ecosystem: official agents for JavaScript/TypeScript (@dfinity/agent / @icp-sdk/core) and Rust (ic-agent), plus community agents for Go, Python, Java, Dart, .NET, Elixir, C, and others. Show basic setup and a query/update call example for the two official agents. Cover canister discovery (env vars, ic_env cookie, PUBLIC_*_CANISTER_ID), the query vs update distinction from the caller perspective (agents route queries to a single replica for speed and route updates through consensus for reliability — Candid annotations determine which type each method uses, and generated bindings handle this automatically), authentication context (anonymous, delegations from Internet Identity), and error handling. Show how generated bindings (from binding-generation) provide a typed interface. Link to community agents for other languages.

• Portal: building-apps/interact-with-canisters/agents/overview (agent concept + language list)

• JS SDK: @icp-sdk/core (https://js.icp.build/core) — HttpAgent, actor creation

• JS SDK: @icp-sdk/canisters (https://js.icp.build/canisters) — canister utilities

• Rust agent: https://docs.rs/ic-agent/latest/ic_agent/

• Go agent (community): https://github.com/aviate-labs/agent-go

• Python agent (community): https://github.com/eliezhao/icp-py-core

• Java agent (community): https://github.com/ic4j/ic4j-agent

• Dart agent (community): https://github.com/AstroxNetwork/agent_dart

• .NET agent (community): https://github.com/Gekctek/ICP.NET

• Elixir agent (community): https://github.com/diodechain/icp_agent

• C agent (community): https://github.com/Zondax/icp-client-cpp

• icp-cli: concepts/canister-discovery.md

• Template: hello-world (frontend calling backend)

• Examples: hello-world (both), whoami (JS frontend)

• guides/canister-calls/candid — interface definitions (shared by all agents)
• guides/canister-calls/binding-generation — generating typed clients
• guides/canister-calls/onchain-calls — canister-to-canister alternative
• guides/frontends/asset-canister — deploying the frontend that makes these calls
• guides/authentication/internet-identity — adding auth to calls