Multi-Provider Voice Routing

Production voice deployments rarely use a single provider for all sessions. Enterprise customers may require specific STT providers for compliance, regional latency differences may favor different TTS engines, and A/B testing demands side-by-side provider comparison. Multi-provider session routing selects the optimal voice provider combination per session based on tenant identity, geographic region, or feature flags — all without code changes. This guide covers implementing a routing layer on top of Beluga AI’s voice/session package.

Overview

Rather than hardcoding a single STT/TTS provider, session routing evaluates context at session creation time and selects the appropriate providers. This supports multi-tenant deployments, A/B testing, and regional optimization without code changes.

Prerequisites

• Go 1.23 or later
• Multiple STT/TTS or S2S providers configured
• Routing criteria defined (tenant, region, feature flags)

Installation

go get github.com/lookatitude/beluga-ai

Configuration

Define Routing Context

Establish what drives provider selection for each session:

type RouteContext struct {
    SessionID string
    TenantID  string
    Region    string
    Features  map[string]bool
}

Implement the Router

Select providers based on the routing context:

import (
    "context"

    "github.com/lookatitude/beluga-ai/voice/stt"
    "github.com/lookatitude/beluga-ai/voice/tts"
    s2spkg "github.com/lookatitude/beluga-ai/voice/s2s"
)

func SelectProviders(ctx context.Context, rc RouteContext) (stt.Provider, tts.Provider, s2spkg.Provider, error) {
    if rc.Features["s2s"] {
        s2sProvider, err := createS2SProvider(ctx, rc.TenantID, rc.Region)
        return nil, nil, s2sProvider, err
    }
    sttProvider, err := createSTTProvider(ctx, rc.TenantID, rc.Region)
    if err != nil {
        return nil, nil, nil, err
    }
    ttsProvider, err := createTTSProvider(ctx, rc.TenantID, rc.Region)
    return sttProvider, ttsProvider, nil, err
}

Use a configuration file or database lookup to map tenant/region to concrete provider types and configurations.

Usage

Create Sessions with Routed Providers

import "github.com/lookatitude/beluga-ai/voice/session"

sttProvider, ttsProvider, s2sProvider, err := SelectProviders(ctx, routeCtx)
if err != nil {
    return nil, err
}
if s2sProvider != nil {
    return session.NewVoiceSession(ctx,
        session.WithS2SProvider(s2sProvider),
        session.WithConfig(session.DefaultConfig()),
    )
}
return session.NewVoiceSession(ctx,
    session.WithSTTProvider(sttProvider),
    session.WithTTSProvider(ttsProvider),
    session.WithConfig(session.DefaultConfig()),
)

Add VAD and Turn Detection per Route

Optionally attach VAD and turn detection providers selected by route:

import (
    "github.com/lookatitude/beluga-ai/voice/vad"
    "github.com/lookatitude/beluga-ai/voice/turndetection"
)

vadProvider, err := vad.NewProvider(ctx, "webrtc", vad.DefaultConfig())
if err != nil {
    return nil, err
}
td, err := turndetection.NewProvider(ctx, "heuristic", turndetection.DefaultConfig())
if err != nil {
    return nil, err
}
sess, err := session.NewVoiceSession(ctx,
    session.WithSTTProvider(sttProvider),
    session.WithTTSProvider(ttsProvider),
    session.WithVADProvider(vadProvider),
    session.WithTurnDetector(td),
    session.WithConfig(session.DefaultConfig()),
)

Configuration Reference

Option	Description	Default
Routing key	Tenant, region, feature flags	Application-defined
Provider map	Tenant/region to STT/TTS/S2S config	Config file or DB
Fallback	Default provider when route is missing	Application-defined

Troubleshooting

Provider not found for tenant

Fall back to a default provider. Log and emit metrics for missing mappings to identify configuration gaps.

Session creation fails after routing

Validate provider configuration at startup or in a readiness check. Return clear errors with the routing context included for debugging.

Switching providers mid-session

The session API does not support swapping providers during an active session. Provider failover requires creating a new session. Design routing logic to execute at session start only.

Advanced Topics

Production Deployment

• Caching: Reuse provider instances per tenant/region to avoid creating new ones for every session
• Observability: Tag metrics and traces with route context (tenant, region) for debugging
• Testing: Unit-test the router with mock providers; integration-test one or two representative routes

Related Resources

• Voice Session Persistence
• Voice Services Overview