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Fixie agents API

The agents API from Fixie — 9 operation(s) for agents.

Fixie agents API is one of 14 APIs that Fixie publishes on the APIs.io network, described by a machine-readable OpenAPI specification and an AsyncAPI event-driven specification.

Tagged areas include Agents. The published artifact set on APIs.io includes an OpenAPI specification, authentication docs, and an AsyncAPI specification.

This API exposes 16 operations across 9 paths, and defines 82 schemas. It is described by OpenAPI 3.0.3, at version 0.1.0.

Requests are made against a single base URL, https://api.ultravox.ai.

16 operations 9 paths 82 schemas 2 DELETE8 GET2 PATCH4 POST

Metadata

The identity and technical contract details declared by the specification.

Specification
OpenAPI 3.0.3
API Version
0.1.0
Base URL
https://api.ultravox.ai/api
Authentication
API Key
Resource Areas
1

Authentication & Security 1

Fixie agents API declares 1 security scheme for authenticating requests. An API key is passed in the header as X-API-Key (apiKeyAuth).

  • apiKeyAuth — API key

Paths & Operations 16

Across 9 paths, the API surfaces 16 operations — 2 DELETE, 8 GET, 2 PATCH, 4 POST. Each is listed below with its method, path, parameters, and response codes.

agents 16
GET
/api/agents
agents_list 4 params → 200
POST
/api/agents
agents_create body → 201
GET
/api/agents/{agent_id}
agents_retrieve 1 param → 200
PATCH
/api/agents/{agent_id}
agents_partial_update 1 param body → 200
DELETE
/api/agents/{agent_id}
agents_destroy 1 param → 204
GET
/api/agents/{agent_id}/calls
agents_calls_list 3 params → 200
POST
/api/agents/{agent_id}/calls
agents_calls_create 2 params body → 201
GET
/api/agents/{agent_id}/scheduled_batches
agents_scheduled_batches_list 3 params → 200
POST
/api/agents/{agent_id}/scheduled_batches
agents_scheduled_batches_create 1 param body → 201
GET
/api/agents/{agent_id}/scheduled_batches/{batch_id}
agents_scheduled_batches_retrieve 2 params → 200
PATCH
/api/agents/{agent_id}/scheduled_batches/{batch_id}
agents_scheduled_batches_partial_update 2 params body → 200
DELETE
/api/agents/{agent_id}/scheduled_batches/{batch_id}
agents_scheduled_batches_destroy 2 params → 204
GET
/api/agents/{agent_id}/scheduled_batches/{batch_id}/created_calls
agents_scheduled_batches_created_calls_list 4 params → 200
GET
/api/agents/{agent_id}/scheduled_batches/{batch_id}/scheduled_calls
List scheduled calls within a batch.
agents_scheduled_batches_scheduled_calls_list 5 params → 200
POST
/api/agents/{agent_id}/telephony_xml
Allows supported telephony providers to create incoming calls with an agent, returning XML instructions for handling the call.
agents_telephony_xml 1 param body → 200
GET
/api/agents/usage
agents_usage_list 10 params → 200

Schemas 82

The contract defines 82 schemas that model the data the API accepts and returns. The most detailed are Call (41 properties), ultravox.v1.CallTemplate (24 properties), ultravox.v1.StartAgentCallRequest (18 properties), ultravox.v1.EnabledDataMessages (13 properties). Each schema is shown below with its type and property counts.

ultravox.v1.CallMedium_WebSocketMedium
object
Details for a WebSocket call.
5 properties
ultravox.v1.CallMedium_WebRtcMedium
object
Details for a WebRTC call.
1 property
ultravox.v1.CartesiaVoice_CartesiaGenerationConfig
object
Cartesia generation configuration for Sonic-3 and later models.
4 properties
RetentionPolicyEnum
string
retain - Retain indefinitely autodelete - Auto-delete after billing
ultravox.v1.TimedMessage
object
A message the agent should say after some duration. The duration's meaning varies depending on the context.
3 properties
ultravox.v1.HeaderApiKeyRequirement
object
A security requirement that will cause an API key to be added to the header.
1 property
google.protobuf.Value
Represents a dynamically typed value which can be either null, a number, a string, a boolean, a recursive struct value, or a list of values.
ultravox.v1.CallMedium_DtmfHandling
object
Configuration for how incoming DTMF digits are handled during a call. When dtmfhandling is absent from the enclosing medium, DTMF digits are sent as a user tex…
2 properties
ultravox.v1.FirstSpeakerSettings_AgentGreeting
object
Additional properties for when the agent speaks first.
4 properties
FirstSpeakerEnum
string
PaginatedScheduledCallList
object
4 properties 1 required
ultravox.v1.ToolRequirements
object
The requirements for using a tool, which must be satisfied when creating a call with the tool.
2 properties
ultravox.v1.ToolOverrides
object
Overrides for a set of selected tools. Items in remove are applied before items in add. Use remove + add for replacements.
3 properties
ultravox.v1.InworldVoice
object
Specification for a voice served by Inworld.
5 properties
ultravox.v1.Callbacks
object
Configuration for call lifecycle callbacks.
3 properties
ultravox.v1.DataConnectionAudioConfig
object
Configuration for audio in data connections
2 properties
ultravox.v1.ElevenLabsVoice_PronunciationDictionaryReference
object
A reference to a pronunciation dictionary within ElevenLabs.
2 properties
PaginatedScheduledCallBatchList
object
4 properties 1 required
ultravox.v1.Message
object
A message exchanged during a call.
12 properties
ultravox.v1.PlivoMedium_OutgoingRequestParams
object
Parameters for a Plivo call creation request.
3 properties
AgentStatistics
object
1 property 1 required
ultravox.v1.ExternalVoice
object
A voice not known to Ultravox Realtime that can nonetheless be used for a call. Such voices are significantly less validated than normal voices and you'll be r…
7 properties
ultravox.v1.BaseHttpToolDetails
object
Details for invoking a tool via HTTP.
2 properties
ultravox.v1.DataConnectionConfig
object
Data connection enables an auxiliary websocket for streaming data messages.
4 properties
ultravox.v1.GenericVoice
object
Specification for a voice served by some generic REST-based TTS API. The API must accept an application/json POST request (as defined below) and return either…
8 properties
ultravox.v1.BaseToolDefinition
object
The base definition of a tool that can be used during a call. Exactly one implementation (http or client) should be set.
13 properties
ultravox.v1.CallMedium_ExotelMedium
object
Details for a Exotel call.
1 property
AgentUsage
object
2 properties 2 required
ultravox.v1.StaticParameter
object
A static parameter that is unconditionally added when the tool is invoked. This parameter is not exposed to or set by the model.
3 properties
PaginatedCallList
object
4 properties 1 required
ultravox.v1.CallMedium_PlivoMedium
object
Details for a Plivo call.
2 properties
AgentDailyUsage
object
3 properties 3 required
NullEnum
PaginatedAgentList
object
4 properties 1 required
TerminationReasonEnum
string
ultravox.v1.VadSettings
object
Call-level VAD settings.
4 properties
ultravox.v1.BaseDataConnectionToolDetails
object
Details for invoking a tool via a data connection.
ultravox.v1.HttpAuthRequirement
object
A security requirement that will cause an HTTP authentication header to be added.
1 property
ultravox.v1.LmntVoice
object
Specification for a voice served by LMNT.
4 properties
ScheduledCall
object
8 properties 4 required
ultravox.v1.StartAgentCallRequest
object
A request to start a call with an existing agent.
18 properties
InitialOutputMediumEnum
string
ultravox.v1.InCallTimespan
object
A timespan during a call.
2 properties
ultravox.v1.TwilioMedium_OutgoingRequestParams
object
Parameters for a Twilio call creation request.
3 properties
ultravox.v1.CallMedium_DtmfUserTextMessage
object
Configures DTMF digits to be sent as a user text message.
2 properties
ultravox.v1.Callback
object
A lifecycle callback configuration.
2 properties
ultravox.v1.CallMedium
object
Details about a call's protocol. By default, calls occur over WebRTC using the Ultravox client SDK. Setting a different call medium will prepare the server for…
7 properties
ultravox.v1.AutomaticParameter
object
A parameter that is automatically set by the system.
3 properties
ultravox.v1.SelectedTool
object
A tool selected for a particular call. Exactly one of toolid, toolname, or temporarytool should be set.
8 properties
ultravox.v1.CartesiaVoice
object
Specification for a voice served by Cartesia. See https://docs.cartesia.ai/api-reference/tts/websocket
6 properties
Agent
object
6 properties 4 required
BillingStatusEnum
string
BILLINGSTATUSPENDING - The call hasn't been billed yet, but will be in the future. This is the case for ongoing calls for example. (Note: Calls created before…
ultravox.v1.SecurityRequirement
object
A single security requirement that must be met for a tool to be available. Exactly one of queryapikey, headerapikey, or httpauth should be set.
3 properties
ultravox.v1.CallMedium_TelnyxMedium
object
Details for a Telnyx call.
2 properties
PatchedScheduledCallBatch
object
12 properties
AgentBasic
object
2 properties 2 required
ultravox.v1.UltravoxCallTokenRequirement
object
A security requirement that will automatically be fulfilled during call creation. The generated token will be set as an X-Ultravox-Call-Token header when the t…
1 property
ultravox.v1.SecurityOptions
object
The different options for satisfying a tool's security requirements.
1 property
ultravox.v1.SipMedium_SipIncoming
object
Details for an incoming SIP call.
PatchedAgent
object
6 properties
ScheduledCallBatch
object
12 properties 6 required
EndReasonEnum
string
unjoined - Client never joined hangup - Client hung up agenthangup - Agent hung up timeout - Call timed out connectionerror - Connection error systemerror - Sy…
Call
object
41 properties 23 required
ultravox.v1.StaticToolResponse
object
A predefined, static response for a tool. When a tool has a static response, it can be returned immediately, without waiting for full tool execution.
1 property
ultravox.v1.EnabledDataMessages
object
Whether certain data messages are enabled for a connection.
13 properties
ultravox.v1.DynamicParameter
object
A dynamic parameter the tool accepts that may be set by the model.
4 properties
ultravox.v1.CallTemplate
object
A CallTemplate that can be used to create Ultravox calls with shared properties.
24 properties
CallSipDetails
object
2 properties 2 required
ultravox.v1.ElevenLabsVoice
object
Specification for a voice served by ElevenLabs.
11 properties
ultravox.v1.SipMedium_SipOutgoing
object
Details for an outgoing SIP call.
4 properties
ultravox.v1.RespeecherVoice
object
Specification for a voice served by Respeecher. See https://space.respeecher.com/docs/api/tts/sampling-params-guide for parameter guidance.
10 properties
ScheduledCallStatusEnum
string
ultravox.v1.QueryApiKeyRequirement
object
A security requirement that will cause an API key to be added to the query string.
1 property
ultravox.v1.GoogleVoice
object
Specification for a voice served by Google. This implementation uses bidirectional streaming, so voices prior to Chirp3 are not supported.
2 properties
ultravox.v1.BaseClientToolDetails
object
Details for invoking a tool expected to be implemented by the client.
ultravox.v1.TelnyxMedium_OutgoingRequestParams
object
Parameters for a Telnyx call creation request.
3 properties
ultravox.v1.FirstSpeakerSettings
object
Settings for the initial message to get a conversation started. Exactly one of user or agent should be set. The default is agent (unless firstSpeaker is also s…
2 properties
ultravox.v1.CallMedium_TwilioMedium
object
Details for a Twilio call.
2 properties
ultravox.v1.CallMedium_SipMedium
object
Details for a SIP call. Exactly one of incoming or outgoing must be set.
2 properties
ultravox.v1.FirstSpeakerSettings_UserGreeting
object
Additional properties for when the user speaks first.
1 property
ultravox.v1.SecurityRequirements
object
The security requirements for a request. All requirements must be met.
2 properties
ultravox.v1.FallbackAgentGreeting
object
A fallback for the case when the user is expected to speak first but doesn't.
3 properties

Specification

The full machine-readable OpenAPI contract behind this narrative.

Source

fixie-agents-api-openapi.yml Raw ↑

Other APIs Fixie publishes across the network.

Fixie accounts API
Fixie api_keys API
Fixie call_throttles API
Fixie calls API
Fixie corpora API
Fixie deleted_calls API
Fixie models API
Fixie schema API
Fixie sip API
Fixie telephony_configs API
Fixie tools API
Fixie voices API
Where this information came from

This is an independent, third-party profile of Fixie agents API, published by API Evangelist. We do not operate, host, resell, or support these APIs, and we are not affiliated with or endorsed by the company unless stated above. Everything here is built from publicly available information — the company's own site, developer portal, documentation, public repositories, and the specifications it publishes for public use. Nothing is obtained by breaching a system, defeating an access control, or using credentials.

The Kin Score and Agent Readiness rating are independently calculated assessments of a company's public API artifacts, scored against a published rubric. They are not certifications, endorsements, security assessments, or audits.

Corrections, re-scores, and removal are free — no partnership or purchase required, and you do not need to justify the request. A removed company is recorded as unrated, never scored zero for having asked. Acknowledgement within one business day; removal within two.

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