Close Tech Stack

Sales CRM with built-in communication, automation, and AI coaching for small-business teams

Software Development San Francisco, California 51–200 employees Founded 2013 Privately Held

Close is a sales CRM built for speed—combining deal management, VoIP, automation, and reporting in a single platform. The tech stack is modern and API-first (Python, Flask, MongoDB, PostgreSQL, Elasticsearch, React, GraphQL, WebRTC), and active projects reveal a pivot toward AI: call assistants, drafting tools, and autonomous reply systems are all under development. The challenge they're facing—syncing millions of emails and calendar events at scale—suggests their customer base is growing faster than their infrastructure can comfortably handle.

Tech Stack 38 technologies

Core StackPython Flask MongoDB PostgreSQL Elasticsearch Redis AWS AWS RDS Docker Kubernetes Terraform Ansible Twilio GraphQL Zoom React React Native Vite Playwright Figma Storybook AWS EKS AWS MSK ElastiCache WebSockets WebRTC Vitest React Testing Library Chromatic Backbone.js+8 more

What Close Is Building

◆Challenges

Implementing new ai features
Improving performance and scalability of api
Syncing millions of sales emails and calendar events
Customer growth
Under-leveraged creative
Zero distribution beyond organic search
Small budget
Manual experimentation process
Slow variant production
Low visibility in llm search

▲Active Projects

New user-facing features
Ai features to turbocharge customers’ daily tasks
Improving performance and scalability of graphql and rest api
React-custom-scroller
Use-infinite-scroll
Ai-powered call assistant
Ai-powered drafting tools
Autonomous reply systems
Internal automation
Conversion-driven creative for website and paid channels

Hiring Activity

Accelerating9 roles · 4 in 30d

Department

Marketing

Engineering

Support

Product

Seniority

Senior

Junior

Staff

Company intelligence

Find more companies like Close by tech stack, pain points and active projects

Get started free

About Close

Close is a bootstrapped, profitable CRM platform for small-business sales teams. The product integrates deal tracking, VoIP calling (via Twilio), email automation, sales coaching, and reporting into one interface, with a design philosophy centered on speed and ease of use. Built by a 100+ person, fully remote team across the United States, Close serves inside-sales operations. Recent hiring has accelerated across marketing, engineering, support, and product roles, and current development priorities are weighted heavily toward AI-driven features (call assistants, email drafting, autonomous responses) alongside API performance improvements.

HeadquartersSan Francisco, California

Company Size51–200 employees

Founded2013

Hiring MarketsUnited States

Frequently Asked Questions

What tech stack does Close use?

Close uses Python and Flask for backend services, MongoDB and PostgreSQL for data storage, Elasticsearch for search, and React for frontend UI. Infrastructure runs on AWS (EKS, MSK, RDS), with Kubernetes and Terraform for orchestration. Communication layers use Twilio, WebRTC, and WebSockets.

What is Close working on?

Close is developing AI features including an AI-powered call assistant, AI drafting tools, and autonomous reply systems. Other priorities include improving GraphQL and REST API performance, building new user-facing features, and internal automation improvements.

Similar Companies in Software Development

Other companies in the same industry, closest in size

How this profile is built

Close's technology stack, projects, and hiring signals are inferred from public hiring and company data — career pages, public listings, and company web presence — then clustered and de-duplicated. Figures are estimates that refresh over time. Read our full methodology →

This is not an official vendor or customer list. It is a technology-adoption signal inferred from public data, intended for B2B research.