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Voice preservation
AI should amplify your voice, not replace it. Every feature we build protects the authenticity of your brand and personal style.
Founded in 2024 in San Francisco
We believe writing should be effortless.
Horizon exists because the best ideas deserve better words. We built an AI writing tool that respects your voice, accelerates your workflow, and gives every team the confidence to publish faster.
Our Story
Born from frustration with generic AI copy
In early 2024, our founders were running a fast-growing B2B startup. They relied on AI writing tools daily for launch posts, investor updates, product copy, and internal communications. But every tool they tried produced the same bland, interchangeable output that sounded nothing like their brand.
The editing overhead was enormous. They spent more time fixing AI-generated text than they saved creating it. Brand guidelines lived in a shared Google Doc that nobody referenced. Tone shifted with every new team member. Quality degraded as the company scaled.
They realized the problem was not the language model itself but the interface layer. Existing tools treated writing as a single-player activity with no memory of who you are, what your brand sounds like, or how your team collaborates. There was no continuity between sessions, no shared context, no approval workflow.
So they built Horizon: an AI writing workspace that remembers your voice, supports team workflows, and makes the jump from draft to published content feel seamless. Within six months, the private beta had over 12,000 users on the waitlist and a 4.9-star satisfaction rating.
2024
Company founded
Three co-founders leave their roles at a Series B startup to solve the AI writing quality problem. Initial prototype built in eight weeks using internal R&D funds.
Q2 2024
Seed round closed
Raised $4.2M seed round led by Y Combinator with participation from Sequoia Scout and a16z. Hired the first five engineers and a head of product.
Q3 2024
Private beta launches
Invited 500 founding users from the waitlist. Iterated on brand voice memory, team workspaces, and the template library based on direct feedback sessions.
Q1 2025
12,000+ on the waitlist
Organic growth from word-of-mouth and founder communities. Preparing for general availability launch with enterprise features and API access.
Mission & Values
What we stand for
These principles guide every product decision, hiring choice, and customer interaction at Horizon.
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Quality over quantity
We would rather help you produce one exceptional piece of content than ten mediocre ones. Our metrics track publish quality, not generation volume.
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Team-first design
Writing is a collaborative act. Shared workspaces, approval flows, and centralized brand guidelines are first-class citizens in our product.
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Radical transparency
We publish our roadmap publicly, share revenue metrics with customers, and openly discuss the limitations of AI-assisted writing.
Founding Team
The people behind the product
A lean team of operators who have shipped products used by millions and raised capital from the best firms in the industry.
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Nadia Reeves
Co-Founder & CEO
Previously VP of Product at a Series B content-tech startup that scaled to 2M monthly active users. Stanford CS graduate. Built the first prototype of Horizon in a weekend hackathon after watching her marketing team spend 40% of their time editing AI output.
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Marcus Park
Co-Founder & CTO
Former Staff Engineer at a major cloud platform where he led the natural language processing team. Published research on controllable text generation at NeurIPS. Architect of Horizon's brand voice memory system that learns user tone from as few as three writing samples.
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Sophie Laurent
Co-Founder & Head of Design
Former Design Director at a design-led SaaS company known for its minimalist interfaces. Led the redesign that increased user retention by 34%. Obsessed with making professional writing tools feel as calm and focused as a notebook, not as overwhelming as a cockpit.
Advisors
Guided by experienced operators
David Chen
Former CTO, ContentStack
Built content management infrastructure serving Fortune 500 companies. Advises on enterprise architecture and scaling.
Elena Vasquez
Partner, Y Combinator
Backed 40+ AI startups over six batches. Provides guidance on go-to-market strategy and founder community building.
James Okonkwo
VP Growth, Notion
Led product-led growth from 1M to 30M users. Advises on viral loops, activation metrics, and freemium conversion.
Priya Sharma
Head of AI, Grammarly
Deep expertise in production NLP systems at scale. Provides technical guidance on language model fine-tuning and evaluation.
Investors
Backed by the best in the business
Our $4.2M seed round is led by firms with deep expertise in developer tools, AI infrastructure, and content platforms.
Y Combinator
Lead Investor (W24 Batch)
Horizon was selected for the Winter 2024 batch. YC provided $500K in initial funding, access to the alumni network, and introductions to enterprise design partners who shaped our beta product.
Sequoia Scout
Seed Participant
Sequoia Scout invested based on the strength of the founding team and early traction metrics. Their portfolio includes multiple content and productivity companies that now serve as potential integration partners.
a16z
Seed Participant
Andreessen Horowitz participated through their AI Fund. Their investment thesis centers on vertical AI applications that solve specific workflow problems rather than horizontal tools that compete on raw model performance.
$4.2M
Total funding raised
3
Institutional investors
7
Angel investors
18+
months of runway
By The Numbers
Momentum speaks louder than promises
12,000+
Teams, founders, and operators on our waitlist, growing at 15% week over week through organic referrals.
4.9/5
Average satisfaction score from our private beta cohort of 500 founding users over a 90-day evaluation period.
82%
Of beta users reported publishing content faster with Horizon than with any previous tool, including manual writing.
14
Full-time team members across engineering, product, design, and go-to-market, distributed across three time zones.
Culture
How we work
We are a distributed team that operates with the intensity of a startup and the intention of a design studio. We ship weekly, demo publicly, and hold each other to a high bar on craft and clarity.
Weekly ship cycles
Every Friday we demo what shipped. No slides, no status updates. Working software or it did not happen. This cadence keeps us honest and our users delighted.
Writing-first communication
We practice what we preach. All major decisions start with a written proposal. We use Horizon internally for product briefs, investor updates, and even our own marketing copy.
Customer obsession
Every engineer and designer joins at least two customer calls per month. Our roadmap is shaped by direct conversations with the people who use our product daily.
Open Positions
Join the team
We are hiring across engineering, design, and go-to-market. If you care deeply about writing, developer experience, and building products that respect user intelligence, we want to talk to you.
Senior Frontend Engineer
Remote (US/EU) · Full-time
ML Engineer, NLP
Remote (US/EU) · Full-time
Product Designer
Remote (US/EU) · Full-time
Head of Content Marketing
Remote (US/EU) · Full-time
Developer Advocate
Remote (US/EU) · Full-time
Ready to write with Horizon?
Join 12,000+ founders and teams who are waiting for the future of AI-assisted writing. Early access invites go out every week.