Overview

Zavu brings messages from supported channels into threads sorted by recent activity, while its API supports sending and receiving across those channels. Automatic routing can choose a channel based on the recipient and the sender’s configured channels, which is useful when a team wants its application to manage channel selection rather than hard-code one route.

The product goes beyond an inbox: agents can respond across messaging channels and phone, draw on agent-specific knowledge bases and memory, and call tools owned by the customer. That breadth suits teams building their own service workflows. It is less attractive to organizations seeking a conventional email help desk with mature, ready-to-use integrations.

Key features

Channels, threads and routing

Supported channels include WhatsApp, SMS, one-way SMS, voice, email, Telegram, Instagram and Messenger. Threads combine messages across a contact’s channels and surface the most recently active conversations first. Automatic channel selection can reduce the work of choosing a destination for each message, but the free plan’s 2,000-message monthly allowance covers only WhatsApp, Telegram, Instagram and Messenger—not every supported channel.

Agents and developer access

Agents can work across messaging and phone, use their own knowledge bases and memory, and invoke customer-owned tools. TypeScript, Python, Ruby, Go and PHP SDKs are joined by an MCP server, agent skills, a CLI, an n8n node and a Vercel Marketplace integration. That is a practical set of entry points for teams building around Zavu; planned integrations with tools including HubSpot, Salesforce, Zendesk and Shopify are not a substitute for integrations already in place.

Webhook security and sending continuity

Webhooks use an HMAC-based X-Zavu-Signature. Version 2, the default for new senders, signs the timestamp together with the body. Sending stops when the prepaid balance reaches zero, although inbound messages and webhooks continue. That separation helps preserve incoming events, but teams relying on outbound replies should monitor and replenish their balance.

Pricing

Free Plan — 0.00 USD per free

Free forever includes two channel connections, 2,000 shared monthly messages across WhatsApp, Telegram, Instagram and Messenger, and $2 in monthly usage credit. It is a useful starting point for a small integration or low-volume workflow, but the connection and message caps make it a poor fit for a growing multi-channel operation. Free users get an in-product assistant and Discord community support.

Pro — 20.00 USD per month

Pro includes $20 in monthly usage credit, unlimited channel connections, 2M memory units per month and prepaid usage. It removes the free plan’s connection ceiling and raises the included credit, making it the clearest fit for teams building and operating a broader integration. The prepaid model still means sending depends on maintaining a positive balance. Direct chat with Zavu engineers is available from 9am to 7pm Eastern Time, Monday to Friday.

Managed — 1250.00 USD per month

Managed is billed at 50% off launch pricing, normally $2,500 per month. It adds weekly conversation review, ongoing tuning and 24/7 support with a 30-minute response SLA. Teams that want continuing operational help may find that more suitable than owning agent tuning themselves; the price is a substantial step up from Pro.

Build — 2450.00 USD per once

Build is billed at 50% off launch pricing, normally $4,900. Zavu designs, builds and ships an agent in the customer’s Zavu account over four to six weeks. It suits teams that want an initial agent implementation without building it from scratch, rather than those looking for an ongoing managed service.

Enterprise — custom pricing

Enterprise uses postpaid invoicing with NET-30 and offers negotiated rates, multi-zone redundancy and an uptime SLA, plus a named engineer. It is the tier to consider when negotiated terms and resilience commitments matter more than prepaid usage.

Voice agents start at $0.07 per minute. Premium models and voices cost extra, and BYOK is unavailable for voice agents, so teams should account for those charges separately when estimating phone-agent usage.

Platforms

Zavu Inbox is available via API and web. The SDKs and developer tools span several common implementation paths, but teams should confirm that the API-and-web model fits their intended support workflow.

Who it's for

Zavu is best suited to developers and product teams that want to build cross-channel messaging into their own applications, route messages programmatically, or deploy agents that can call customer-owned tools. Pro is the more sensible starting point once two connections or 2,000 covered monthly messages are not enough.

It is not the strongest fit for teams that primarily need a ready-made shared email help desk or depend on a broad set of established CRM and support integrations. Zapier, Make, HubSpot, Salesforce, Shopify, WooCommerce, Zendesk, Intercom and GitHub are marked as coming soon.

Pros and cons

Pros

Broad channel coverage: Messaging spans social, chat, email, SMS and voice, with inbox threads that bring a contact’s channels together.
Developer-oriented access: Five language SDKs, an MCP server, CLI, agent skills, n8n node and Vercel Marketplace integration give teams multiple ways to connect Zavu to their stack.
Flexible agent workflows: Agents can use dedicated knowledge bases and memory and call customer-owned tools, rather than being limited to canned replies.
Inbound continuity at zero balance: Inbound messages and webhooks keep working even when prepaid sending is rejected.

Cons

Restrictive free allowance: Two connections and 2,000 shared monthly messages cover only four channels, limiting the plan’s usefulness for broader production workloads.
Outbound depends on prepaid funds: Sending is rejected at zero balance, so teams must actively manage usage credit.
Voice adds cost and constraints: Agents start at $0.07 per minute, premium options cost extra, and BYOK is unavailable for voice agents.
Several desired integrations remain forthcoming: Teams depending on the named CRM, commerce or support platforms cannot treat those connections as current integrations.

Alternatives

Shared Inbox Software is a useful place to compare products if a conventional shared inbox matters more than a developer-first messaging API.

Help Scout is worth considering when a freemium support product with a free plan and trial, API access, and a Free plan covering five users, one inbox and one Docs site better matches the team’s needs.
Cerb may suit teams seeking a freemium option with unlimited workers and seats on its Community plan, or a licensed self-hosted plan at 40.00 USD per month.
Drag is an alternative for teams looking for paid shared inboxes in Gmail with Kanban, list and preview board views; its Starter plan is 16.00 USD per month.
Gmelius may fit teams that prefer a paid product with an annual Meli plan at 19.00 USD per month for up to five users and 5,000 email conversations per month.
Hiver is an option for teams seeking a freemium shared-inbox product, with a Growth plan at 25.00 USD per month billed annually for two shared inboxes and ten users.
Sortd is worth a look when shared boards and mailboxes are the priority; its Starter plan is 10.00 USD per month billed annually and caps users at ten.
Front may suit teams seeking a paid platform with a Starter plan at 25.00 USD per month billed annually, up to ten seats, and ten channels per license.
SupportBee is another paid API-and-web option, with a Startup plan at 20.00 USD per month for one knowledge base, one team and unlimited email inboxes and tickets.

Verdict

Choose Zavu Inbox if your team wants a developer-oriented way to combine messaging channels, routing and configurable agents in its own stack. Its breadth of channels and integration tools is the strongest reason to choose it; the free-plan ceilings, prepaid sending dependency and additional voice costs are the reasons to look elsewhere—or to budget carefully before expanding beyond a prototype.

	Coherence	Zavu Inbox
Free plan	Yes	Yes
Free trial	Yes	No
Paid from	$12/mo	$20/mo
Open source	No	No
Platforms	Android, api, Web	api, Web
Free plan	Yes	—
Internal comments	Yes	Yes
Collision detection	Yes	—
Mail platforms	gmail and outlook	standalone
Mobile apps	Yes	—

Coherence vs Zavu Inbox

Coherence

Zavu Inbox