OpenAI Realtime API vs Unreal Speech

Comparing the features of OpenAI Realtime API to Unreal Speech

Feature
OpenAI Realtime API
Unreal Speech

Capability Features

Asynchronous Requests
Dashboard Access
Enterprise Privacy Commitment
Expanded Model Support Planned
Five New Voices
5
Function Calling
Human and Automated Safety Monitoring
Interruption Handling
Max Audio Duration
10 hours
Max Monthly Characters
7000000000
No Training on Data Without Permission
Per-sentence Timestamps
Per-word Timestamps
Playground Access
Production Ready Infrastructure
Prompt Caching Planned
Public Beta
Reference Client Available
Six Preset Voices
6
Speech-to-Speech
Streaming Audio Inputs/Outputs
Streaming Endpoint
Streaming Latency
0.3s
Supported Audio Codecs
libmp3lamepcm_mulaw
Supported Bitrates
320k256k192k128k96k64k48k32k16k
Supported Language List
US EnglishUK EnglishMandarin ChineseHindiSpanishPortugueseJapaneseFrenchItalian
Supported Voices
48
Supports Text and Audio Inputs
TextAudio
Synchronous Requests
Text-to-Speech API
/stream/speech/synthesisTasks/streamWithTimestamps
Ultra Low Latency
Uptime SLA
99.9%
Usage Commercial Rights
Voice Parameter Control
SpeedPitch
WebSocket Connection
WebSocket Streaming

Integration Features

Agora Integration
API Documentation
API Integration
PythonNode.jsReact NativeBash
Chat Completions API Integration
LiveKit Integration
OpenAI Node.js SDK Planned
OpenAI Python SDK Planned
Sign In Methods
GoogleEmail
Supported Export Formats
MP3PCM µ-law
Supports GPT-4o
gpt-4o-realtime-preview
Twilio Voice API Integration

Limitation Features

AI Disclosure Requirement
Attribution Requirement
Free plan requires attribution
Audio Only Modality (Initially)
Lower Session Limits Tiers 1-4
Lower than 100
Max Characters /speech
3000
Max Characters /stream
1000
Max Characters /synthesisTasks
500000
No Simultaneous Session Limit Anymore
Simultaneous Sessions Limit Tier 5
100
Usage Policy Restriction
Voice Cloning

Other Features

Affiliate Program
Comparison to Competitors
AmazonMicrosoftGoogleElevenLabsPlay.ht

Pricing Features

Additional Usage Price
Basic - $16 per 1M charactersPlus - $12 per 1M charactersPro - $10 per 1M charactersEnterprise - $8 per 1M characters
Approximate Audio Input Price
$0.06/minute
Approximate Audio Output Price
$0.24/minute
Elite Plan Quota
625000000
Enterprise Plan Price
$4999/month
Free Characters Limit
250000
Free Plan Rollover
Free Tier
No Free Tier
Paid Plan Rollover
Pricing Audio Input
$100/1M tokens
Pricing Audio Output
$200/1M tokens
Pricing Cached Audio Input
$20/1M tokens
Pricing Cached Text Input
$2.50/1M tokens
Pricing Text Input
$5/1M tokens
Pricing Text Output
$20/1M tokens
Subscription Plans
BasicPlusProEnterprise
Trial Period