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This page defines every Unpod term once. Other pages link here instead of redefining things. If a definition seems to conflict elsewhere, this page wins. The one rule that explains the whole architecture: the wire between Unpod and your code carries text, not audio. Unpod owns the phone call, the speech, and the carriers. You own the brain that decides what to say. Everything below follows from that split.

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Architecture at a Glance

A single inbound call, end to end:
Animated Unpod voice stack diagram showing phone, browser, and mobile entrypoints flowing through the managed speech layer into your AgentRunner, dialog machine, and tools.
Read it as: a Caller enters through a phone number, browser, or mobile app. For phone calls, the Number routes over a Trunk into Unpod’s managed speech layer. Unpod transcribes the audio with the call’s voice profile (STT) and sends plain text across the Bridge over a WebSocket to your AgentRunner. Your runner hands each turn to your Agent (your brain). Your reply text crosses back over the Bridge, Unpod synthesises it (TTS), and the caller hears it. SuperDialog is one option for the brain - powerful, but optional. You own everything from the AgentRunner down. Everything above it is managed.

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Glossary

One canonical definition each. Headings are anchor-able, so other pages can deep link (for example /get-started/core-concepts#pipe).

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Number

A phone number callers dial. Inbound calls arrive on a number and route to the Speech Pipe it is attached to. Numbers come from Unpod directly or you bring your own (BYON). You never configure a carrier. See Numbers.

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Trunk

The SIP connection that carries calls between a telephony provider and Unpod. A trunk is the source of phone numbers: you register a trunk, then sync its numbers into Unpod. You configure a trunk once; after that you work with numbers, not SIP. See Trunks.

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Voice Profile

A bundle of STT + TTS provider configuration: which providers recognise and synthesise speech, which language and voice, latency, and failover order. Profiles are a read-only catalog you pick from - you reference one by name or profile_id when creating a Speech Pipe. See Voice Profiles.

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Pipe

A Speech Pipe is the configuration entity that binds a call together: a name, a voice profile, recording and duration settings, and the agent_id that points at your runner. Numbers attach to a pipe; outbound calls run through a pipe. The pipe is the anchor that connects a number, a voice profile, and your agent. See Pipes.

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Bridge

The text-routing seam inside Unpod between the speech pipeline and your code. Transcribed caller text crosses the Bridge to your AgentRunner; your reply text crosses back to be synthesised. The Bridge is why your code never touches audio. It is Unpod-internal infrastructure - you do not configure it; you’ll see the term in WebSocket frame names and in the legacy Bridges API.

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Agent (Brain)

Your conversation logic - whatever decides what to say next. It can be a SuperDialog DialogMachine, a LangChain chain, a plain HTTP endpoint, or custom Python. Unpod is brain-agnostic: it routes text in and text out. “Agent” and “brain” mean the same thing here. See Bring Your Agent.

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AgentRunner

A long-lived Python process you run. It registers with the Unpod orchestrator over WebSocket, advertises capacity, and serves a per-call bridge that Unpod dials into. For each call it builds a CallContext and invokes your entrypoint. You identify it with an agent_id (see IDs You’ll Meet). See SDK Setup.

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Session

Your control interface for one live call, reached as ctx.session. It exposes controls (say(), transfer_to_human(), end(), recording controls), hooks, metrics, and the dialog_machine slot where you plug in your brain. Calling session.run() keeps the call alive and routes each transcribed turn to your brain. See Session Controls.

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CallContext

The per-call metadata envelope your entrypoint receives: async def entrypoint(ctx: CallContext). It carries call_id, session_id, agent_id, direction ("inbound" or "outbound"), user_number, any instructions and data from dispatch, and the live session you control the call through.

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Space

A Platform concept, not an SDK one. A Space is a workspace container in the Unpod Platform that organises agents, tasks, runs, and data. The Platform’s REST API addresses a space by its space token. You only meet spaces when you use the hosted Platform or its REST API - the voice SDK does not require one.

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Two APIs

The unpod SDK package contains two distinct halves. Know which one you are using.
Management APIConnectivity API
ProtocolREST (HTTPS)WebSocket (WSS)
Entry pointClient / AsyncClientAgentRunner / Session
PurposeProvision resourcesHandle live calls
You call itBefore callsDuring calls
Examplesclient.numbers, client.voice_profiles, client.pipes, client.trunks, client.callsAgentRunner(...).start(), ctx.session.say(...)
Management API is for setup and orchestration: register a trunk, sync numbers, create a Speech Pipe, trigger an outbound call, fetch transcripts. You construct a Client (sync) or AsyncClient (async); it reads UNPOD_API_KEY from the environment. 
from unpod import AsyncClient

client = AsyncClient()                       # REST, reads UNPOD_API_KEY
pipe = await client.pipes.create(name="support", agent_id="support-bot")
Connectivity API is for the call itself: your AgentRunner holds a persistent WSS connection to the orchestrator, and each call gives you a live Session to act on. 
from unpod import AgentRunner, CallContext

async def entrypoint(ctx: CallContext) -> None:
    await ctx.session.say("Hello")           # WSS, live call
    await ctx.session.run()

AgentRunner(entrypoint=entrypoint, agent_id="support-bot").start()

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IDs You’ll Meet

Four identifiers cause most first-run failures. They are not interchangeable.
agent_id and pipe_id are different things. Mismatching them is the most common reason a call never reaches your runner. The agent_id you pass to AgentRunner(...) must exactly match the agent_id on the Speech Pipe.
IDWhat it identifiesWhere it comes from
agent_idYour runner pool - which AgentRunner should handle a callA string you choose. Passed to both AgentRunner(agent_id=...) and client.pipes.create(agent_id=...). They must match exactly.
pipe_idOne Speech Pipe in the Speech StackA UUID Unpod assigns when you create the pipe. Used in REST calls (numbers.attach, calls.create).
Space tokenA Platform workspaceA token from the Platform’s Spaces API. Used only in the hosted Platform and its REST API, not in the voice SDK.
Runner agent IDSame as agent_idJust another name for agent_id as seen from the runner side. Internally the runner derives a worker_id (<agent_id>#<random>) per process, but you never set that.
Wiring it correctly: 
# 1. Pipe says: route my calls to the "support-bot" agent.
pipe = await client.pipes.create(name="Support", agent_id="support-bot")
print(pipe.pipe_id)   # UUID from Unpod -> use in REST calls

# 2. Runner says: I am the "support-bot" agent.
AgentRunner(entrypoint=entrypoint, agent_id="support-bot").start()
#                                            ^^^^^^^^^^^^
#            must equal the pipe's agent_id, or calls never arrive
If a call rings but your runner never wakes up, check this match first.

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Naming: The Four Product Terms

Unpod is one company with one platform, described at four altitudes. Use these terms precisely.
TermWhat it means
UnpodThe company and the platform as a whole - everything below combined.
Speech StackThe voice infrastructure plus the unpod SDK: numbers, trunks, voice profiles, pipes, STT/TTS, and the AgentRunner runtime. This is what a Python dev builds against.
SuperDialogThe optional dialog framework (superdialog package): flow graphs, tools, and state for structured conversations. One choice of brain - not required.
PlatformThe hosted UI and self-hostable stack: dashboard, agent studio, spaces, analytics, and telephony management on top of the Speech Stack.

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Next Steps

Make Your First Call

Wire a number, a pipe, and a runner end to end.

Speech Stack

Numbers, voice profiles, pipes, and the AgentRunner SDK.

SuperDialog

The optional framework for structured conversation flows.

Session Controls

Act on a live call - say, transfer, end, record.