What The World's Best Startups Are Building

Cofia

Learns how you work and proactively creates automations without prompts or manual setup.

Zapier requires you to define the automation. Cofia watches your system events and anonymized network traffic, then proactively creates automations you did not ask for. Zero-prompt automation is a different product category from workflow builders.

CatchBack Cards

Lets creators build mystery packs with cryptographically fair odds and instant physical fulfillment.

Trading card mystery packs are a $5B+ market built on trust that the odds are fair. CatchBack open-sources its card selection code with cryptographic proofs, letting creators build packs that buyers can verify. $13K MRR with 700 users and a Steph Curry collaboration launching.

Clice AI

Gives each team member a personal AI agent that coordinates with teammates' agents automatically.

Most AI agent platforms give one agent to a whole team. Clice gives each team member their own agent that coordinates with teammates' agents, turning scheduling, handoffs, and ticket updates into agent-to-agent communication rather than human overhead.

Chamber

Reduces the $240B in annual GPU waste by automating infrastructure optimization for ML teams.

Companies waste an estimated $240B annually on GPU compute. Chamber's founder built Amazon's GPU orchestration project and AWS CloudWatch Application Signals, so he has seen the problem from inside the largest cloud provider and knows exactly where the waste hides.

CodeWisp

Lets anyone create real 2D, 3D, and multiplayer games from a text description, no coding required.

The founder taught game development to 22M+ people on YouTube and built two game engines from scratch. CodeWisp lets anyone describe a game in plain English and publish it instantly, with 4,100+ developers already on the platform.

Caretta

Gives sales reps real-time answers and objection handling during live calls from org-wide knowledge.

Sales reps on technical products freeze when a prospect asks a question they cannot answer. Caretta joins the call live, pulls from the company's entire knowledge base, and surfaces the answer in real time. The difference between winning and losing a deal is often one unanswered question.

Captain

Delivers 95%+ accurate knowledge search across unstructured enterprise data, beating standard RAG.

RAG accuracy plateaus around 80% for most implementations. Captain claims 95%+ by running parallel LLM queries across document chunks and aggregating results, which is a brute-force approach that works if the orchestration is fast enough. SOC 2 certified.

Carrot Labs

Keeps production AI agents reliable by continuously fine-tuning against business metrics.

Most AI agent teams monitor in production and fine-tune separately. Carrot Labs closes the loop: it evaluates agent performance against business metrics and selectively retrains, which means the agent improves without a human deciding what to fix.

Cardboard

Lets teams edit professional video through natural language commands in the browser, no NLE needed.

Professional video editing still requires a $2,000 NLE and years of training. Cardboard runs in the browser, takes natural language commands, and exports to Premiere and DaVinci. Highest-upvoted HN launch in YC W26 suggests the developer community is paying attention.

Cascade

Evaluates and certifies AI agents for safe deployment with red teaming and formal guarantees.

Red teaming and guardrails exist as separate tools. Cascade combines them into one platform with adaptive scaffolding that learns from production runs, already deployed across legal reasoning and customer support agents. The CEO researched graph reasoning and agentic safety at UC Berkeley's BAIR Lab.

Cardinal

Runs precision outbound for 40+ YC companies, replacing 7+ tools with one AI workflow.

Outbound sales teams stitch together 7+ tools (Apollo, Instantly, Clay, LinkedIn, etc.) and lose signal between them. Cardinal consolidates the stack into one workflow and already runs outbound for 40+ YC companies, which is strong proof from a demanding buyer set.

10xScience

Turns weeks of manual protein analysis into minutes for drug development teams.

Canary

Replaces manual QA with AI that reads your code, understands changes, and writes tests per PR.

QA engineers are expensive, slow, and first to get cut. Canary reads your code diffs, understands the intent behind each change, and generates targeted Playwright tests per PR. Teams are hitting 90%+ coverage in days instead of weeks.

Cajal

Deploys AI mathematicians that formally verify proofs, grounding outputs in truth not guesses.

LLMs hallucinate. Lean proves things. Cajal pairs LLMs with formal verification so every mathematical result is machine-checked, starting with quantum computing and finance where a wrong proof costs real money.

Button Computer

A privacy-first wearable AI that only listens when pressed, no always-on mic or cloud needed.

Humane and Rabbit tried always-on AI wearables and both failed on privacy and form factor. Button only listens when physically pressed, which is a better privacy model, and two ex-Apple Vision Pro engineers know how to ship hardware that people actually wear.