Every AI boom builds two shadows: the infrastructure underneath it and the security that keeps it safe. In the 2026 cohort those shadows are 54 startups strong: 29 infrastructure companies and 25 security companies in our database. This page lists twenty across both categories and charts the rest by batch.

1. Twenty security and infrastructure startups

Newest batch first, category marked on every row. The full lists live on the security and infrastructure category pages, and both are searchable through the platform search.

CompanyWhat it doesCategoryBatchHQ
Armorer LabsContinuous security verification for AI agents in regulated industriesAI SecurityYC Fall 2026San Francisco, CA, USA
AucertA team of expert AI agents that test mobile apps on their own.AI SecurityYC Fall 2026San Francisco, CA, USA
EpsilabLong horizon RL environments from real-life dataAI InfrastructureYC Fall 2026San Francisco, CA, USA
Hesper AIAI Claims Investigator for InsuranceAI SecurityYC Fall 2026New York City, NY, USA
HopperInference and post-training for realtime agentsAI InfrastructureYC Fall 2026San Francisco, CA, USA
isoquantSelf-optimizing inference cloud for faster, cheaper AIAI InfrastructureYC Fall 2026San Francisco, CA, USA
LatentCatch wrong LLM answers before your customers doAI SecurityYC Fall 2026San Francisco, CA, USA
Liquid EnergySelf contained solar-powered AI inference modules: the NanoDCAI InfrastructureYC Fall 2026Waterloo, ON, Canada
LyonFoundation models on enterprise transaction data.AI SecurityYC Fall 2026San Francisco, CA, USA
Munito AIOpen-model inference provider for Europe, private by default.AI InfrastructureYC Fall 2026Paris, Île-de-France, France; Remote
OpenHackAlways-on AI security engineerAI SecurityYC Fall 2026San Francisco, CA, USA
OpenLake TechnologiesOpenLake deploys, trains, and serves models that update in real time.AI InfrastructureYC Fall 2026San Francisco, CA, USA
RoutantLast mile deployment and connectivity for Agents as a ServiceAI SecurityYC Fall 2026San Francisco, CA, USA
Sentient OSOn-device AI that knows your entire life and does your work overnight.AI InfrastructureYC Fall 2026San Francisco, CA, USA
StacktraceSee and control what your agents actually doAI SecurityYC Fall 2026San Francisco, CA, USA
SynaraBuilding the next generation of AI enabled monitoringAI SecurityYC Fall 2026San Francisco, CA, USA
BaudAI chips for ultra-fast training and inferenceAI InfrastructureYC Summer 2026San Francisco, CA, USA
BelvedirAutonomous AI Model TrainingAI InfrastructureYC Summer 2026San Francisco, CA, USA
ConiferLeast cost routing system to reduce 70%+ token spendAI SecurityYC Summer 2026San Francisco, CA, USA
DecaworkTraining company-specific models that approve AI actions.AI SecurityYC Summer 2026San Francisco, CA, USA

2. Infrastructure peaks in summer, security holds steady

Infrastructure spikes in Summer 2026 with 14 of its 29 companies, while security arrives evenly: 3 in Winter, 4 in Spring, 9 in Summer and 9 in Fall. That shape makes sense. Infrastructure sells to the builders of the current wave, so it follows batch energy; security sells to everyone deploying AI, a demand that does not care which batch is graduating.

3. Why this pair matters

These 54 companies rarely make launch day headlines, but they decide what the other 459 can build and how safely it runs. If you track one quiet corner of the cohort, track this one. Founders in either category list free, and readers can compare them against established tools in our free FreeTier Finder.

4. Reading the two lists

The infrastructure 29 sell the substrate: compute and inference platforms, data pipelines, agent runtimes, evaluation and observability. Their customers are the other 484 companies on this site. The security 25 sell trust: model and agent security, data protection, identity for non human actors, and the audit trail regulators keep asking for. Their customers are everyone deploying AI into a business that can be fined.

A useful exercise: pick any five startups from the complete list and find their likely suppliers and their likely security vendors on these two category pages. The cohort increasingly sells to itself, and these 54 are where that internal economy concentrates.

Both category pages update as new batches publish, and both are small enough that a quarterly re-read keeps you current on the whole field.

Source: AIToolGuide 2026 startups database (513 AI companies), compiled from Y Combinator 2026 batch listings and the TrustMRR and Indie Hackers marketplaces.