Stamp vs Shortwave: Which AI Inbox in 2026?
Both of these are AI-native inboxes that read your mail, draft replies in your voice, and organize threads for you, so the choice comes down to maturity and scope. Shortwave is an AI-powered Gmail client built by ex-Google Inbox engineers, best known for natural-language search across your entire email history, its Ghostwriter drafting, and Tasklet automations. Stamp (stampmail.ai, YC W25) is a newer AI-native inbox that drafts and prioritizes like Shortwave but also reaches into calendar and scheduling, with an editor-like composer and a mobile voice mode. The one distinction that decides most of this: Shortwave is a proven, Gmail-only client with the deepest AI search, while Stamp is a younger product with a broader task scope. Name whether your bottleneck is finding and answering mail inside Gmail or a single tool that also touches your calendar, and the pick gets obvious. For the wider field, see best AI email tools and best AI inbox management tools.
The One-Sentence Answer
Use Shortwave if you live in Gmail and want the most mature AI search and drafting client; use Stamp if you want a newer AI-native inbox that also handles calendar and scheduling and you’re fine being early.
Side-by-Side Comparison
| Dimension | Stamp | Shortwave |
|---|---|---|
| What it is | AI-native inbox and calendar assistant (YC W25) | AI-native Gmail client (ex-Google Inbox team) |
| Core job | Draft, prioritize, summarize email and schedule | Search, summarize, draft, and organize Gmail |
| Standout feature | Editor-like composer, “Stamp Mode” approvals, calendar handling | Natural-language search over full history, Ghostwriter, Tasklet automations |
| Voice-matched drafts | Yes | Yes (Ghostwriter) |
| Calendar / scheduling | Yes | Light |
| Automations | Basic AI labels and actions | Tasklet, multi-step across many apps |
| Email providers | Connects to existing accounts; provider list not clearly documented | Gmail only (no Outlook, IMAP) |
| Platforms | Web, iOS, Android | Web, Mac, iOS, Android |
| Pricing (2026) | Free 30-day trial; Personal $20/mo; Business $50/mo | Free tier; paid plans from about $14/seat/mo, scaling to team tiers |
| Maturity | Newer, small team | Established, larger user base |
When to Use Stamp
- You want one tool that drafts your email and schedules meetings, not just an inbox client.
- You like an editor-like composing experience with inline autocomplete and highlight-to-edit.
- You want to move fast through your inbox by approving the AI’s suggested changes (“Stamp Mode”).
- You want a mobile voice mode to delegate tasks by talking.
- You’re comfortable adopting a newer YC-stage product that’s still filling out.
Stamp bets on being agentic and cross-surface early. That breadth is the draw, and the trade-off is that it’s a young product with a smaller track record than Shortwave.
When to Use Shortwave
- Your email lives in Gmail and you’re not moving off it.
- Your biggest pain is finding things: buried confirmations, old threads, “what did we agree on.”
- You want the most polished AI search and summaries available in a mail client.
- You want Ghostwriter to draft in your voice and Tasklet to automate multi-step workflows across other apps.
- You value a mature, stable client over the newest feature set.
Shortwave is the safer, more proven pick if Gmail search and drafting is the whole job. Its one hard limit is that it does not support Outlook or other non-Gmail accounts.
The Difference That Actually Decides It
Strip away the feature lists and it’s a maturity-versus-scope call. Shortwave does one surface, Gmail, extremely well, with search and drafting that are hard to beat. Stamp does more surfaces, email plus calendar, but it’s newer and less battle-tested. If Gmail search is your real problem, Shortwave wins on depth. If you want email and scheduling handled by the same assistant and can tolerate being early, Stamp’s breadth is the reason to try it.
There’s a limit both share, though. Each one drafts the reply, summarizes the thread, and lines up the work, but neither actually finishes it. You still click send, you still confirm the meeting, you still update the CRM by hand. If what you want is the outcome rather than a faster draft, that’s a different category of tool. Carly is an AI assistant whose agents each have their own email address and reply to people, book meetings, send follow-ups, and update your CRM on their own, working with Gmail or Outlook across 200+ integrations; you set it up by describing what you want in plain English, and it starts at $35/month.
Quick Reference
| Your situation | Pick |
|---|---|
| I live in Gmail and want the best AI search | Shortwave |
| I want one tool for email and calendar | Stamp |
| I’m fine adopting a newer, smaller product | Stamp |
| I want a mature, proven client | Shortwave |
| My email is in Outlook | Neither is a clean fit today |
| I want the reply sent and the meeting booked for me | Neither — see Carly |
FAQ
Does Stamp work with Outlook? Stamp says it connects to your existing email accounts, but it does not clearly document which providers it supports, so confirm on stampmail.ai before switching if you’re on Outlook. Shortwave is Gmail-only and does not support Outlook at all.
Which has better AI search? Shortwave. Natural-language search over your entire email history is its signature strength, built by the team behind Google Inbox. Stamp offers semantic search too, but Shortwave’s is the more proven implementation.
Is Stamp free? Stamp offers a 30-day free trial, then Personal at $20/month and Business at $50/month. Shortwave keeps a free tier plus paid plans that start around $14/seat/month and scale up for teams; verify current numbers on each site, since both change pricing.
What if I want the email actually handled, not just drafted? Both tools help you write and organize faster, but you’re still the one sending, booking, and updating records. If you’d rather delegate the outcome, an AI assistant like Carly acts on the work directly across Gmail or Outlook rather than handing you a draft.
Related: Stamp alternatives · Shortwave alternatives · Best AI email tools · Best AI inbox management tools
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