A better email client, or a cross-channel agent.
Spark by Readdle is a genuinely good email client. Its Smart Inbox surfaces what matters, the experience is fast and clean across iOS, macOS, Android, and Windows, and Spark AI helps you compose and summarize. this+that is not an email client. It is an agent that works across Gmail, Outlook, Slack, Teams, Google Chat, and Telegram, and turns what it finds into tasks and workflows.
A better way to do email vs. a way to do less email
Spark's thesis is that email should feel calm and fast: a Smart Inbox that prioritizes for you, clean design on every device you own, and team features like shared drafts and private comments for handling mail together. That thesis is well executed, and Spark is a pleasure to use. this+that's thesis is different: the problem is not that email clients are bad. The problem is that messages, across email, Slack, Teams, and Google Chat, create work that doesn't get done because it's scattered, untracked, and manual. If you want a polished inbox on every platform, Spark is a strong choice. If you want the work that comes from all your messages to happen automatically, this+that is built for that.
Feature by feature
How the two products compare across the things that matter most.
| Topic | Spark | this+that |
|---|---|---|
| Core philosophy | A fast, well-designed email client for every platform. Smart Inbox prioritization, a calm experience, and team email collaboration. | Delegate the work that follows messages. Extract tasks, run workflows, keep teams in sync, across whatever channels work arrives through. |
| Platforms | Native apps for iOS, macOS, Android, and Windows. A strength: the same inbox on every device. | Web app plus a Chrome extension. One unified inbox across connected channels rather than a per-device email client. |
| Channels | Email only. Connects Gmail, Outlook, iCloud, and other mailboxes; does not read Slack or Teams messages. | Gmail, Outlook, Slack, Teams, Google Chat, Telegram, Google Calendar, and Outlook Calendar treated as one stream of incoming work. |
| Inbox prioritization | Smart Inbox groups and prioritizes email automatically, so the important messages rise to the top. Clean and effective. | A unified inbox across channels with AI triage, focused on turning messages into tracked work rather than sorting email alone. |
| AI writing | Spark AI drafts replies and summarizes threads inside the client. A helpful, well-integrated composer. | Interactive AI reply button drafts from your direction and your brain, and draft-reply also runs as a workflow action. Lighter on trained voice-matching. |
| Task extraction | Not a persistent task layer. You can pin, snooze, and set reminders on emails, but tasks are not extracted automatically. | Automatic. DoBox reads every conversation and extracts requests, decisions, follow-ups, commitments, and deadlines as trackable, assignable tasks. |
| Workflow automation | No workflow builder. Automation is limited to inbox rules, reminders, and follow-up nudges. | Full workflow builder. 32 action types. Plain-language creation. Conditional logic, loops, sub-agents. Not limited to inbox triggers. |
| Team features | Shared drafts, private comments on emails, delegation, and +Team plans. Strong for handling a shared mailbox together. | Shared task view, task assignment, workflow delegation to teammates. Work-level coordination across channels, not just email coordination. |
| Knowledge base | No shared team knowledge layer. The AI works from the content of your email. | The Brain: a shared knowledge base of your team’s own policies and docs that grounds the AI’s answers and workflow decisions. |
| External integrations | Calendar and file-service connections, plus integrations with a set of popular apps for the inbox experience. | Open MCP standard. GitHub, Notion, Jira, Dropbox, HubSpot, and any tool with an API. |
| Pricing | A free tier plus paid Premium and +Team plans. | Free during beta. |
- Smart Inbox prioritization is genuinely good: it groups and surfaces the email that matters so you spend less time sorting.
- The experience is fast and clean, and it looks and feels consistent across iOS, macOS, Android, and Windows.
- Native apps on every major platform mean the same inbox on your phone, laptop, and desktop.
- Spark AI is a well-integrated composer and summarizer for drafting replies and catching up on threads.
- Team email features are thoughtful: shared drafts, private comments on emails, and delegation for handling mail together.
- Snooze, reminders, and follow-up nudges make it easy to stay on top of an inbox without extra tools.
- Reads Slack, Teams, and Google Chat alongside email, all channels treated as one stream of incoming work. Spark is email only.
- Task extraction: every message across all channels is scanned for requests, commitments, and deadlines, surfaced automatically in DoBox.
- Workflow automation: 32 action types with conditional logic, loops, and sub-agents, built in plain language, not just inbox rules.
- A shared knowledge base of your team’s policies and docs grounds the AI’s answers and workflow decisions.
- Work-level team coordination across channels, with a human approval step before work is handed to the right person.
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