Overview

Rainbow brings persistent one-to-one and group chat, presence, task management, file sharing, voice and video calling, and screen or app sharing together. Eligible plans add telephony capabilities such as PBX control, VoIP, call logging, caller identification, forwarding and voicemail. That breadth may reduce the need to bridge separate communication tools, particularly for businesses with existing telephony infrastructure. It is less suited to teams whose priority is large video meetings: the stated meeting limit is two participants.

Businesses can deploy Rainbow in cloud, on-premises or hybrid configurations. It is available in more than 75 countries and 22 languages, with web, Windows, macOS, Android, iPhone, iPad and Android TV apps.

Key features

Telephony and integrations

Rainbow combines VoIP calling and phone presence with PBX control and, on eligible plans, call forwarding and voicemail. It also supports call recording and auto attendant. Hybrid telephony can connect with OmniPCX Enterprise and OXO Connect, as well as third-party CTI and Media Bridge integrations for Cisco, NEC, Mitel and Asterisk. That makes it a credible option for organizations extending current phone systems rather than replacing them outright.

Office integrations include Chrome Click2Call, Rainbow Telephony for Microsoft Teams, Microsoft 365 Exchange Online or Google Calendar, and an Outlook plug-in. These connections help place Rainbow alongside familiar office tools, although the specific telephony features depend on plan eligibility.

CPaaS and security

The CPaaS developer platform exposes APIs for contact management, chat, voice, video, screen sharing, file storage, group collaboration and automation bots. Production usage includes monthly allowances of 2,000 administration API calls, 5,000 Bots and Resource API calls, 500 WebRTC minutes and 5 GB of storage before invoicing. Those quotas give developers room to build integrations, but API-heavy deployments need to track consumption.

Security capabilities include AES-256 encryption at rest and in transit, region-based data residency, and SAML or OIDC single sign-on across the listed plans. Compliance capabilities include ISO/IEC 27001, French HDS, GDPR, ANSSI CSPN, Spain ENS, Italy AgID, HIPAA, FERPA and UK NHS support. Business and Enterprise include 24/7 support, a 20-minute first response time and a 99.9% guaranteed uptime SLA; Essential instead provides a digital Help Center.

Pricing

Rainbow uses a freemium model, with Essential free and paid tiers billed per user each month. The subscriptions page offers free trials or demonstrations for some offers, specifically Rainbow Hub and the Rainbow Telephony for Microsoft Teams connector.

Rainbow Essential: Free. It allows one administrator, one-to-one audio, video and screen sharing, 1 GB storage and bubbles for up to 20 users. It is a practical no-cost starting point for an individual administrator, but not a broad collaboration tier.
Rainbow Business: 2.00 EUR per month, billed per user. It includes one-to-one audio, video and screen sharing, 1 GB storage, 20-user bubbles and an SLA. It adds service assurance over Essential, but retains the same one-to-one sharing and storage limits.
Rainbow Enterprise: 4.00 EUR per month, billed per user. It raises sharing to groups of up to 10 users, storage to 20 GB and bubbles to 100 users, while including an SLA. The higher allowance suits larger teams, though it still does not address meetings beyond the stated two-participant limit.

Business and Enterprise include 24/7 support with a 20-minute first response time and a 99.9% guaranteed uptime SLA; Essential is supported through a digital Help Center.

Platforms

Rainbow supports Android, iOS, macOS, web and Windows, as well as an API. Android TV apps are also available. The range suits mixed-device organizations and teams building custom connections through the developer platform.

Who it's for

Rainbow is aimed at businesses from small companies to multinational organizations. It is particularly well matched to organizations that need chat and collaboration alongside hybrid or cloud telephony, PBX connectors, or programmable communications. Essential can serve a single administrator exploring the service; the paid tiers are more relevant when per-user service assurance or larger collaboration groups matter. Teams that routinely need multi-person video meetings should look elsewhere.

Pros and cons

Pro: Hybrid and cloud telephony plus connectors for named PBX systems let businesses build around existing phone infrastructure.
Pro: The API platform covers messaging, voice, video, file storage and automation, with defined monthly production allowances.
Pro: Business and Enterprise pair 24/7 support with a 20-minute first response time and 99.9% uptime SLA.
Con: Essential and Business limit audio, video and screen sharing to one-to-one, while Enterprise tops out at 10 users.
Con: The stated meeting participant limit is two, which rules Rainbow out for teams needing larger meetings.
Con: Essential provides only a digital Help Center rather than the paid tiers' SLA-backed support.

Alternatives

Unified Communications Software is a useful category to compare if Rainbow's mix of telephony and collaboration is not the right fit.

Microsoft Teams is worth considering for a free option that supports 100 participants, 60-minute group meetings and 5 GB of cloud storage.
Webex App is an alternative for free meetings of up to 100 attendees, capped at 40 minutes.
Hubgets may suit teams wanting a free cloud tier for up to 20 users, with 1 GB storage per user.
3CX is another free option for telephony, with a 10-user limit and four simultaneous calls on its free tier; its license must be renewed manually each year.
Alcatel-Lucent Enterprise Rainbow is a related freemium option with a free service for individual use.
Dialpad Support is a paid alternative with a free trial.
Zoom Workplace is an alternative with a free tier that supports 100 participants and 40-minute meetings.
Mitel Secure Cloud is a paid alternative with Essential and Elite service packages.

Verdict

Choose Rainbow if your business needs collaboration tools tied to cloud or hybrid telephony, particularly where PBX connections or CPaaS APIs are central. Its support and uptime commitments strengthen the paid tiers for organizations that need dependable service. Look elsewhere if larger video meetings are essential: the two-participant meeting limit is the clearest constraint.

	Mitel One	Rainbow
Free plan		Yes
Free trial		Yes
Paid from		€2/mo
Platforms	Android, iOS, macOS, Web	Android, api, iOS, macOS, Web, Windows
Business calling	Yes	Yes
Team messaging	Yes	Yes
Video meetings	Yes	Yes
Call recording	Yes	Yes
Free plan		Yes
Auto attendant		Yes
Meeting participant limit		2 participants

Mitel One vs Rainbow

Mitel One

Rainbow