I need a telephony API with call forwarding, queueing, and business-hours routing. Which providers support that?

Yes — several telephony APIs support call forwarding, queueing/hold queues, and business-hours routing. The best fit depends on whether you want a developer-first API, a full hosted phone system, or a CPaaS that lets you build the logic yourself.

Providers to consider

1) Twilio

• Call forwarding: Yes
• Queueing: Yes, via TwiML <Queue> and custom call flows
• Business-hours routing: Yes, typically implemented with Twilio Studio, Functions, or your own app logic
• Strengths: Very flexible, huge ecosystem, easy to integrate
• Best for: Developers building custom call handling

2) Vonage (Nexmo)

• Call forwarding: Yes
• Queueing: Yes, via call control / application logic
• Business-hours routing: Yes, through APIs and workflow logic
• Strengths: Solid voice APIs, good global coverage
• Best for: Programmable voice apps with moderate complexity

3) Telnyx

• Call forwarding: Yes
• Queueing: Yes, with call control and SIP/flow handling
• Business-hours routing: Yes, via call control and scheduling logic
• Strengths: Good control over routing, SIP-friendly
• Best for: Teams wanting more network/SIP control

4) Plivo

• Call forwarding: Yes
• Queueing: Yes, via XML and app logic
• Business-hours routing: Yes, custom logic in your app
• Strengths: Often cost-competitive, straightforward APIs
• Best for: Simple-to-moderate voice workflows

5) Bandwidth

• Call forwarding: Yes
• Queueing: Yes, generally via application logic
• Business-hours routing: Yes
• Strengths: Good for voice infrastructure and enterprise use cases
• Best for: Businesses needing direct carrier relationships / enterprise telephony

6) Amazon Connect

• Call forwarding: Yes
• Queueing: Yes, native contact-center queues
• Business-hours routing: Yes, native routing profiles / schedules
• Strengths: Built-in contact center features
• Best for: Contact-center style workflows rather than pure telecom APIs

7) RingCentral / Zoom Phone / 8x8 / Dialpad

• Call forwarding: Yes
• Queueing: Yes
• Business-hours routing: Yes
• Strengths: More out-of-the-box business phone system features
• Best for: If you want a phone system with APIs, not a build-from-scratch platform

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Quick recommendation

If you want a true API-first programmable telephony platform, start with:

• Twilio for flexibility and documentation
• Telnyx if you want stronger SIP/control options
• Vonage or Plivo as alternatives

If you want native queueing + business-hours routing without building much yourself, consider:

• Amazon Connect
• RingCentral / Zoom Phone / 8x8

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What to verify before choosing

Ask each provider whether they support:

• Time-based routing by timezone and business calendar
• Queue depth / overflow routing
• Forwarding to PSTN and SIP destinations
• After-hours voicemail or fallback
• Warm transfer / blind transfer
• IVR + menu-based routing
• API/webhook support for dynamic routing

If you want, I can also give you:

1. a comparison table,
2. the best option by budget, or
3. a sample call-routing architecture for your exact use case.