Developer Tools Startups

Hal9 is a technology startup founded by a former RStudio engineer; this page is a memorial tribute to Juraj Slugen, an early advisor and mentor to the company. The page does not describe the company's product in concrete terms.

1 investor

Hall runs a messaging service for business teams that works across operating systems and devices. It delivers real-time, SMS-style conversations to mobile and desktop users, targeting companies that want internal communication available wherever employees are.

1 investor

Hammerstone is a software development consultancy run by two developers specializing in backend framework work for clients building web applications.

1 investor

Handover provides a live stress-testing service for Standard Operating Procedures (SOPs) across incident response, data breach, supply chain, and payment operations. The platform guides teams through their SOPs under timed conditions to surface gaps, stale information, and missing decision owners before incidents occur.

1 investor

Hanji extracts structured data from documents including forms, insurance claims, faxes, and scanned PDFs, returning text, tables, and figures with source citations. The platform serves healthcare and claims processing teams that require accuracy and auditability for eligibility, billing, and approval workflows.

1 investor

Hannon Hill builds content management and personalization software for organizations with complex web ecosystems, serving higher education, healthcare, government, and mission-driven organizations. The company focuses on helping web teams manage and optimize digital experiences at scale while maintaining governance and accessibility.

1 investor

Hansel Onboard is a feature adoption manager that helps product teams drive feature discovery and adoption through no-code nudges for mobile applications. It serves mobile-first product teams looking to highlight new features, re-educate users, and guide them through product interactions.

1 investor

hapi is an open-source Node.js backend framework with zero external dependencies, secure defaults, and a plugin-based extensibility model, aimed at developers and enterprise teams building scalable server applications. Originally developed to handle Walmart's Black Friday traffic, it emphasizes security, code quality, and predictability for large distributed engineering teams.

1 investor

Hardhat is a development environment for Ethereum smart contracts, providing tools for testing, deployment, debugging, code coverage, and verification, with a runtime rewritten in Rust for performance. It serves Solidity developers ranging from individual builders to engineering organizations, supporting tests in both Solidity and TypeScript along with an extensible plugin ecosystem.

1 investor

Hardware Intelligence builds an agent-native toolchain for chip design, starting with Wave, an agentic waveform debugger for terminal use.

1 investor

Harper Systems provides a unified runtime that consolidates data, logic, and application functions into a single memory space, eliminating the fragmentation of traditional microservices architectures. The platform is designed for developers and AI coding agents to build applications with reduced latency and infrastructure complexity.

1 investor

Genesis Molecular uses deep learning and molecular simulation to accelerate drug discovery and development. The platform helps identify and optimize drug candidates for challenging diseases.

1 investor

Bitfab is a platform for testing, building, and optimizing multi-turn AI agents and data pipelines through scenario simulation and replay. It captures production data interactions and enables engineers to safely test agent behavior with mocked external calls and defined outcomes.

1 investor

Hatch Early Learning provides digital learning platforms and data analytics tools designed to help early childhood education programs maximize federal, state, and local funding while supporting school readiness, literacy, and social-emotional development.

1 investor

Hats Protocol provides onchain programmable role management for organizations, enabling automated onboarding and permission administration across decentralized systems. The protocol serves DAOs and organizations looking to streamline operational workflows through blockchain-based role infrastructure.

1 investor

Havik Solutions develops portable military training and simulation systems using commercial off-the-shelf hardware and advanced gaming technology, serving U.S. Department of Defense operators and units for mission readiness, call-for-fires training, and distributed combat scenario exercises.

1 investor

Haystack is a GitHub-integrated system that evaluates AI-generated pull requests by analyzing code context, diffs, agent reasoning, and test results to determine whether changes can be merged, require fixes, or need human review. It helps engineering teams manage high volumes of AI-generated code changes while maintaining quality standards and focusing human review effort on complex decisions.

1 investor

Heal creates production-like local sandboxes from a codebase and runs automated end-to-end tests to find bugs, aimed at software development teams using coding agents. It also documents codebases into specs for spec-driven development and keeps sandboxes, specs, and tests in sync as code changes.

1 investor

Helicone provides infrastructure for AI companies to route, debug, and analyze their applications. The platform serves developers and organizations building AI systems.

1 investor

Helio provides crypto checkout, deposit, and subscription tools that let merchants accept payments in stablecoins and other digital assets, with instant settlement or auto-conversion to fiat. It offers self-serve merchant accounts, Pay Links, card onramps, and embeddable SDKs and a Shopify plugin for e-commerce, gaming, and app developers.

1 investor

Helios developed runtime application security tooling using eBPF and OpenTelemetry-based data collection at the platform, kernel, and application levels to give security and development teams visibility into how applications behave in production. The company was acquired by Snyk, which is integrating its runtime intelligence into its application security posture management (ASPM) platform.

1 investor

Helium builds a platform for self-improving software that automatically optimizes mobile app experiences. The company initially focuses on paywall optimization for mobile applications.

1 investor

Helivan builds monitoring and evaluation tools for AI systems, including real-time observability for multi-agent systems to detect behavioral changes and emergent behaviors. It also offers evaluation frameworks that integrate into existing evaluation workflows, spanning use from research to production.

1 investor

Helix is a database built on object storage that combines knowledge graphs, vectors, temporal and full-text search capabilities for AI agents, retrieval-augmented generation (RAG), and enterprise knowledge management applications.

1 investor