Running a business off your personal cell works right up until it doesn’t. Clients text you at 11 p.m. Your number ends up on a flyer you can’t take back. And when you hire someone, there’s no clean way to hand off calls without handing over your phone.
A second phone number app fixes that. You get a separate business line, with its own calls, texts, and voicemail, that lives on the phone you already carry. No second SIM, no desk handset. The good ones add what a personal line never gave you: call recording, a shared inbox, an auto-attendant, and now AI that writes up every call for you.
There are a lot of these apps, and they’re not built for the same person. Some are consumer tools for keeping your real number private. Others are full business phone systems that happen to run on mobile. This list focuses on the ones built for business use: solo operators, small teams, and growing companies that live on the phone.
How we picked
We looked at five things that actually matter once a second line becomes your main line:
- Setup and mobile experience. Can one person get a number and start calling in minutes, from their phone?
- What’s included, from calling and texting to voicemail and, increasingly, AI call notes.
- Team features like shared numbers, call routing, and a shared inbox once you’re more than one person.
- Pricing you can read. Flat per-user rates beat surprise add-ons.
- Where it works. US and Canada coverage at minimum, plus international if you need it.
Here are the five that hold up.
1. Allo — best AI-first option for small teams
Allo is a mobile-first business phone system built for small teams and salespeople, and it’s the most modern option on this list. You get a business number on your existing phone, then AI records and transcribes every call, writes the summary, and syncs it to your CRM automatically. The follow-up notes write themselves.
That’s the real difference. Most second-number apps stop at “here’s a separate line.” Allo treats the call as data. It drafts your follow-up, updates the contact in your CRM, and lets you search old calls by what was actually said. And when you can’t pick up, the AI Receptionist answers, qualifies the lead, and books the appointment for you.
Best for: small sales and support teams that want AI call notes without paying enterprise prices.
Key features: business number with free porting, unlimited national calls, two-way SMS, missed-call text-back, call recording and transcription, AI summaries, AI Receptionist, native CRM sync (HubSpot, Salesforce, Pipedrive, Attio and more), and a power dialer on the Business plan.
Pricing: Starter is $18/user/month (single user, billed annually). Business is $32/user/month billed yearly, or $45 month-to-month, and includes AI plus CRM integrations. Every paid plan includes the AI features at no extra cost, with no AI add-ons. One number is included, and extra numbers are $5/month. There’s a 7-day free trial, no setup fees, and no contract.
Pros: AI is bundled into every plan instead of sold as a costly upsell, the mobile app is genuinely built mobile-first, CRM sync is native, and pricing is flat and easy to read.
Cons: it’s aimed at small and modern teams, so very large contact centers with complex workflows may want something heavier. Coverage is strongest for US and international calling rather than niche local-number markets.
2. Google Voice — best free-to-cheap pick for solos
Google Voice is the default second number for a lot of people, and for good reason: the personal version is free, the interface is clean, and if you already live in Google Workspace it drops right in.
The catch is that “free” is strictly for personal use now. For business, you need a Workspace subscription, and the feature set is deliberately basic: two AI features (spam blocking and voicemail transcription), no CRM integrations, and numbers limited to the US and Canada.
Best for: solopreneurs and Workspace users who want a simple, cheap separate line and nothing fancy.
Key features: voice and text, voicemail transcription, spam filtering, and a local number for each user.
Pricing: the standalone business Starter plan is $10/user/month (US only, one user). Inside Workspace, plans run $10 (Starter), $20 (Standard, adds call recording and routing), and $30 (Premier) per user per month.
Pros: free for personal use, cheap for business, unlimited US texting, and unlimited calls across the US, Canada, and most of Europe.
Cons: requires a paid Workspace plan for real business use, no CRM integrations, no dedicated support on the free tier, and some number-porting and location restrictions.
3. Quo (formerly OpenPhone) — best for collaborative small teams
Quo, the product that rebranded from OpenPhone in 2025, was built to solve exactly this problem: founders running a company off their personal number. It’s polished, easy to use, and strong on collaboration.
The standout is the shared inbox. Multiple people can work the same number, thread conversations, tag teammates, and leave internal notes, which makes it a natural fit for a small team splitting inbound calls and texts. There’s a lightweight built-in CRM and an AI agent (Sona) that can answer calls.
Best for: startups and small teams that want a clean shared line with light CRM built in.
Key features: voice and text, shared inbox with threading and tagging, internal team chat, call routing, AI call transcripts and summaries, and integrations with HubSpot, Salesforce, Attio, Slack, and Zapier.
Pricing: Starter is $19/user/month (local number, unlimited US/Canada calling and texting, voicemail transcripts, 10 AI-handled calls). Business is $33/user/month and adds AI call summaries, analytics, and CRM integrations. Scale is $47/user/month. There’s a 7-day free trial; extra numbers are $5/user/month.
Pros: clean, intuitive interface, well-reviewed support, and genuinely good team collaboration.
Cons: cold calling isn’t allowed and can get your account flagged, the mandatory texting registration can be slow, and the spam filtering is thin.
4. Nextiva — best all-in-one for growing support teams
Nextiva is less “second number app” and more a full communications platform (UCaaS) that includes a business line. If you want voice, video meetings, team chat, SMS, and even light ticketing under one roof, it covers a lot of ground.
That breadth is the trade-off. It’s optimized for larger and support-heavy teams; the entry plan leaves out features smaller competitors include by default, and the good AI features sit behind its most expensive tier.
Best for: US-based SMBs and mid-market teams that want voice, video, and chat from a single provider.
Key features: voice, text, video conferencing, team chat, WhatsApp and Instagram channels, detailed analytics, and CRM integrations including HubSpot, Salesforce, and Zendesk.
Pricing: Core is $23/user/month, Engage is $50/user/month, and Power Suite CX is $75/user/month (where the AI transcription and summarization live). Voicemail transcription is included on all plans; the AI Receptionist is billed separately.
Pros: true all-in-one platform, strong analytics, physical desk-phone support, and the ability to run webinars and online fax.
Cons: the basic plan lacks call routing and recording, essential-tier plans skip CRM integrations, SMS registration can take weeks, and coverage is US-only.
5. RingCentral — best for heavy integration needs
RingCentral has been around since 1999, and it shows in both directions. It’s reliable, it works in around 100 countries, and it has an integration for practically everything: 500-plus native connections including Salesforce, Microsoft Teams, HubSpot, and Pipedrive.
It’s also legacy software. The interface can feel overwhelming for a small team, support tends to prioritize bigger accounts, and cancellation is notoriously painful. You have to call in, answer security questions, and give 30 days’ notice.
Best for: established teams that need deep integrations and international coverage and don’t mind the complexity.
Key features: voice, text, video, and messaging; 500+ integrations; call recording; AI summaries; and an AI Receptionist available as an add-on.
Pricing: Core is $30/user/month, Advanced is $35/user/month, and Ultra is $45/user/month. The AI Receptionist and conversation intelligence are paid add-ons on top.
Pros: huge integration library, strong fax and video tools, multi-location line support, and a large community and knowledge base.
Cons: pricey for small businesses, unlimited calling is capped to the US and Canada, and canceling is genuinely difficult, so plan for the 30-day notice.
Quick comparison
| App | Best for | Starting price | AI included? | Coverage |
| Allo | AI-first small teams | $18/user/mo | Yes, all plans | US + 190+ intl |
| Google Voice | Solos on a budget | $10/user/mo | Basic only | US + Canada |
| Quo | Collaborative small teams | $19/user/mo | From Starter | US + Canada |
| Nextiva | All-in-one support teams | $23/user/mo | Top tier only | US only |
| RingCentral | Heavy integration needs | $30/user/mo | Add-on | ~100 countries |
How to choose
Start with team size. If you’re a solo operator who just needs to stop giving out your personal number, Google Voice or the Starter tier of Allo or Quo will do it cheaply. If you’re a small team splitting inbound calls, look hard at the shared-inbox tools. Quo and Allo are both built for that.
Then decide how much the call notes matter. If you’re in sales or support and you’re losing time writing up calls and updating your CRM by hand, the AI-first options pay for themselves fast, and Allo is the one that bundles that AI into every plan instead of charging extra for it. If you mostly need a reliable line with a deep integration stack and you have the budget, RingCentral or Nextiva cover the enterprise end.
The last filter is pricing you can trust. Flat per-user pricing with AI included beats a cheap headline rate that balloons once you add the features you actually need.
FAQ
Can I keep my current number? Usually, yes. Most of these apps port an existing number for free, though timing varies from minutes to a few days depending on the provider.
Do second number apps work over Wi-Fi? Yes. These are cloud (VoIP) apps, so they route calls over the internet, which is handy for spotty-signal offices and international travel.
Is a free second number app enough for business? For a solo side project, maybe. But free tiers skip call recording, CRM sync, team features, and support. Once the line becomes how customers reach you, a paid plan is worth it.
What’s the difference between a second number app and a full phone system? It’s a spectrum. Apps like Google Voice are simple second lines; platforms like Allo, Nextiva, and RingCentral are full phone systems that run on mobile and add routing, analytics, and AI.
Which one should you pick?
For most small businesses in 2026, the decision comes down to how much you want the phone to work for you. Google Voice is the budget floor. Quo is the collaborative pick. Nextiva and RingCentral cover teams that need an all-in-one platform and can absorb the cost and complexity.
But if you want a second business number that also records your calls, writes the summaries, updates your CRM, and answers when you can’t, all bundled into a flat price, Allo is the one built for exactly that.
Pricing and features reflect each provider’s published information at the time of writing and can change, so check current plans before you buy.
