Inboxero vs OmniFocus vs Things 3: Which GTD App Actually Handles Multi-Source Capture?

OmniFocus and Things 3 are the gold standard GTD apps for a reason. They're polished, they're fast, and serious productivity practitioners have trusted them for years. But they were both designed around a specific assumption: that you'll manually add items to them.

That assumption made sense in 2010. It makes less sense when your working day involves Gmail, Slack, Google Calendar, and possibly three other tools, each generating its own pile of things that need to become next actions.

This comparison looks at how Inboxero, OmniFocus, and Things 3 each handle the capture-to-processing pipeline for knowledge workers who live across multiple digital tools.

What We're Actually Comparing

All three apps support GTD concepts like next actions, projects, contexts, and waiting-for lists. That's table stakes at this point. The more useful question is: what happens between "a commitment enters your life" and "it becomes a defined next action in your system?"

That gap is where most GTD systems fail. The comparison below focuses on that gap.

Capture: Where Items Come From

OmniFocus has a share extension for iOS and Mac that lets you capture from other apps, a dedicated inbox, and support for email-to-OmniFocus forwarding via a special address. Zapier integrations exist but are unofficial and fragile. There's no native Gmail or Slack sync.

Things 3 has a similar approach: a share extension, a quick-entry shortcut, and email-to-Things via a dedicated inbox email address. Elegant, fast, but also entirely manual. If you don't remember to forward the email or use the share extension, the item doesn't exist in Things.

Inboxero connects directly to Gmail (starred emails or labeled messages), Slack (saved messages), and Google Calendar (events with action-item tags) via OAuth. Items appear in the capture queue automatically, within minutes of being flagged in the source app. You don't forward anything or use a share extension. You just star the email and it shows up.

For someone who uses Gmail and Slack heavily, this is a meaningful difference. With OmniFocus or Things 3, capturing a Slack message requires you to open the item, use the share extension, and manually send it to your inbox. With Inboxero, you save the message and forget about it until your next processing session.

Processing: The GTD Clarify Flow

OmniFocus gives you an inbox and lets you convert inbox items into actions or projects. It doesn't guide you through the GTD clarify steps explicitly. You're expected to know the workflow and apply it yourself. Experienced GTD users appreciate this flexibility. Newer practitioners find it easy to skip steps and end up with an inbox full of items that were captured but never properly clarified.

Things 3 takes a similar approach, with a slightly more streamlined interface. The Today view and upcoming list are genuinely well-designed. But again, the clarify workflow is implicit, not explicit. You're not asked "is this actionable?" You're just shown an inbox item and expected to decide.

Inboxero builds the GTD clarify flow directly into the processing view. Clicking an inbox item opens a focused view that walks through the decision tree: is it actionable? If yes, classify it as a Next Action, Project, Waiting For, Someday/Maybe, Reference, or Trash. Assign a context and project. The next item loads automatically. Keyboard shortcuts (1-6 for classification, Z to undo) make the flow fast once you're familiar with it.

This explicit structure is more useful than it might sound. GTD practitioners who've been at this for years often skip the clarify step and treat their task managers as simple to-do lists. Inboxero makes skipping harder, which tends to produce a cleaner system over time.

Weekly Review

OmniFocus has a Review perspective that shows projects you haven't reviewed recently. It's genuinely useful and has been refined over many versions. But it doesn't know about your Gmail starred emails or your Slack saved messages, so a full review still requires checking multiple places.

Things 3 doesn't have a dedicated review mode. You're expected to build your own review workflow, typically by going through each area and project manually.

Inboxero generates the weekly review from live data. The review checklist tells you specifically how many unprocessed items are in the queue, which projects have no next action, which Waiting For items are older than two weeks, and how long it's been since you reviewed your Someday/Maybe list. Each item links directly to the relevant view. Review history and streak tracking are available on the Pro tier.

Pricing

OmniFocus 4 is $99.99 for Mac (one-time) or $9.99/month for the subscription that covers all platforms. The standard tier is $4.99/month.

Things 3 is $49.99 for Mac, $9.99 for iPhone, $19.99 for iPad, all one-time purchases. No subscription.

Inboxero is free for up to 2 source connections, 50 queue items, and 5 active projects. Pro is $19/month with unlimited connections, queue items, projects, and full review history.

Who Should Use Which

OmniFocus is the right choice if you want maximum flexibility, deep customization, and don't mind that capture from external tools requires manual steps. It's a power tool for GTD practitioners who've been doing this for years and have their own capture habits dialed in.

Things 3 is the right choice if you want a beautiful, fast task manager with minimal learning curve and you're comfortable manually adding items. It doesn't try to enforce GTD structure, which is a feature or a bug depending on your preferences.

Inboxero is the right choice if multi-source capture is your primary problem. If you spend meaningful time every day flagging things in Gmail and Slack that then need to make their way into a GTD system, removing that manual transfer step changes how the system feels to use. The processing workflow and data-driven weekly review are built for practitioners who want the GTD structure enforced rather than optional.

You can try the free tier at Inboxero with two source connections and see whether automated capture changes your processing habits before committing to anything.

FAQ

Can OmniFocus connect to Gmail or Slack directly? Not natively. You can use email-to-OmniFocus forwarding or third-party Zapier integrations, but neither approach is officially supported or as reliable as a direct OAuth connection.

Is Things 3 good for GTD? Things 3 supports the core GTD concepts (inbox, projects, areas, someday) and many practitioners use it successfully. It doesn't enforce the GTD clarify workflow explicitly, so the structure you get out depends heavily on the habits you bring in.

What's the best GTD app for teams? All three tools are primarily designed for individual use. If team visibility into tasks matters, tools like Asana or Linear are better fits. GTD is generally a personal productivity system rather than a team collaboration system.

Does Inboxero replace OmniFocus or Things 3? For most GTD practitioners, yes. Inboxero covers capture, processing, next actions, projects, contexts, waiting-for, someday/maybe, and weekly review. If you have specific OmniFocus features you rely on (like complex custom perspectives), there may be a transition period, but the core GTD workflow is fully supported.

Is $19/month worth it for a GTD app? That depends on how much the productivity gap costs you. GTD practitioners who already pay for OmniFocus subscriptions or who combine multiple paid tools (Todoist plus Notion, for example) are often spending more than $19/month for a system that still requires manual steps between tools.