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Upstream
The first inbox built for both humans and AI agents
Last verified August 15, 2026 · Updated daily
What Upstream is building
Email has survived every wave of technology that was supposed to kill it. Instant messaging did not kill it. Slack did not kill it. AI assistants have not killed it. But the way the inbox works has barely changed since the 1990s. Upstream's bet is that this is about to change for a different reason: AI agents. The existing inbox was built for one person managing their own messages. Upstream is rebuilding it from scratch for a world where a team might include three humans and seven AI agents, all operating in the same shared context. The product handles both simultaneously. AI agents can read, write, organise, and act on behalf of users natively, without being bolted onto a traditional client through an integration. Threads are unified across collaborators so everyone, human and agent alike, sees the same context and conversation history. Users retain control over what agents can access, draft, and send. Customer data is never used to train external models. The vision Louis Lecat has articulated: "The future of work isn't one person and one assistant. It's teams of humans and agents working together." The product is live today after months of invite-only beta. It connects to existing email infrastructure so users do not need to migrate anything.
Why this matters
The timing is not arbitrary. The AI agent ecosystem has crossed a threshold in 2025 and 2026: agents are now writing emails, booking meetings, following up on threads, and handling inbox triage for millions of knowledge workers. All of that activity is happening inside email clients that were never designed for it. Gmail and Outlook are retrofitting AI features onto architecture that was designed for solo human use. The unified thread view, the agent permission model, the collaborative context layer: none of these exist natively in any email client in widespread use. Upstream is building the native version. Connect Ventures' participation is the product thesis in investor form. They back exceptional consumer and SaaS product companies with strong design sensibility: Typeform, Hotjar, and MURAL are all in their portfolio. Their check on Upstream signals the conviction that the product quality is differentiated, not just the idea. The angel roster is a credibility multiplier. The Algolia founders (Nicolas Dessaigne and Julien Lemoine) backing Louis Lecat, their own former Head of Product, is a direct endorsement of the person who built the product function at one of France's most successful developer-tools companies. The Framer founders (Koen Bok and Jorn van Dijk) investing signals they believe the UX approach to rebuilding email is technically and aesthetically credible. Xavier Niel, whose Station F houses the team, is the most prominent individual investor in the French tech ecosystem.
Open roles at Upstream
4 positions we're tracking. Roles are re-checked daily and removed when filled.
Founding Engineer (Full-Stack, Email Infrastructure)
First seen 2 months ago
AI/Agentic Systems Engineer
First seen 2 months ago
Product Designer (Communication UX)
First seen 2 months ago
Growth / Product Marketing (Early)
First seen 2 months ago
Hiring outlook
Very High. Two live engineering roles on YC's Work at a Startup posted today. Product just launched publicly. The company has explicitly said they are looking for "an exceptional engineer to build an amazing company with us." No other ATS presence. Direct outreach to founders is the door.
Working at Upstream
Upstream is The first inbox built for both humans and AI agents, founded in and now <50 people. At this stage, expect broad remit, direct access to founders, and equity that still means something if the company works out.
Unspecified is where most Upstream positions are located.
Frequently asked questions
How many jobs does Upstream have open?
We're tracking 4 active openings at Upstream (verified June 2026).
Does Upstream hire remotely?
Currently, Upstream only has in-office roles in Unspecified.
What roles is Upstream hiring for?
Upstream is hiring across Engineering, Design, Marketing. The most recent opening is Founding Engineer (Full-Stack, Email Infrastructure).
How do I apply for a job at Upstream?
Click through to apply, or see our detailed guide on landing a job at Upstream.
Where is Upstream based?
Upstream is headquartered in Unspecified.
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