Close Tech Stack

Sales CRM with built-in calling, messaging, and AI coaching for small-business teams

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

Close is a self-contained sales platform (CRM + VoIP + automation + reporting) targeting small businesses that want speed over feature bloat. The tech stack — Python/Flask on AWS with PostgreSQL, MongoDB, Elasticsearch, and Redis — supports real-time communication via Twilio, WebSockets, and WebRTC. Active projects center on AI feature rollout (call assistant, task automation) and API scalability (GraphQL/REST), while internal pain points surface a company wrestling with email/calendar sync at scale and rebuilding systems around AI — indicating a shift from traditional CRM toward AI-augmented workflows.

Tech Stack 41 technologies

Core StackPython Flask MongoDB PostgreSQL Elasticsearch Redis AWS AWS RDS Docker Kubernetes Terraform Ansible GitHub Twilio GraphQL Figma Zoom React React Native Vite Playwright AWS EKS AWS MSK ElastiCache WebSockets WebRTC REST API Vitest React Testing Library Chromatic+10 more

What Close Is Building

◆Challenges

Implementing new ai features
Improving performance and scalability of api
Syncing millions of sales emails and calendar events
Friction reduction
Time-to-value acceleration
Customer growth
Fraudulent low-effort applications
Optimizing engineering hiring
Rebuilding internal systems around ai
Slow sales and marketing workflows

▲Active Projects

New user-facing features
Ai features to turbocharge customers’ daily tasks
Improving performance and scalability of graphql and rest api
Onboarding flows
A/b tests
Pricing and packaging experiments
Technical sourcing engine
React-custom-scroller
Use-infinite-scroll
Ai-powered call assistant

Hiring Activity

Accelerating10 roles · 6 in 30d

Department

Engineering

Marketing

Support

Design

Seniority

Senior

Junior

Lead

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About Close

Close sells a CRM platform purpose-built for inside sales teams and small businesses. The product integrates calling (via Twilio), email, and calendar sync with deal management, automation, and reporting in a single interface. The company is bootstrapped and profitable, remote-first, and based in San Francisco. With ~100+ employees across engineering, marketing, support, and design, Close prioritizes asynchronous work and deep focus. Recent hiring velocity is accelerating across engineering and marketing roles, with active projects focused on AI-powered features, API performance, and onboarding friction reduction.

HeadquartersSan Francisco, California

Company Size51–200 employees

Founded2013

Hiring MarketsUnited States

Frequently Asked Questions

What tech stack does Close use?

Python, Flask, PostgreSQL, MongoDB, Elasticsearch, Redis, AWS (EKS, MSK, RDS, ElastiCache), Docker, Kubernetes, Terraform, Ansible, GraphQL, REST API, React, React Native, Twilio for VoIP, and WebRTC for communication.

What is Close working on?

AI-powered features (call assistant, task automation), GraphQL/REST API performance and scalability, user onboarding flows, pricing experiments, and a technical sourcing engine. Internal priorities include syncing millions of sales emails/calendar events and reducing time-to-value.