---
title: 'Haskell Developer at Co–Star'
canonical: 'https://feeny.ai/job/haskell-developer-co-star-remote-dme63y8pa5wb'
type: 'job'
last_seen: '2026-09-09'
---

# Haskell Developer at Co–Star

- **Company:** Co–Star
- **Location:** Remote
- **Work type:** remote
- **Posted:** 2025-01-16
- **Last confirmed live:** 2026-09-09
- **Apply:** https://job-boards.greenhouse.io/costar/jobs/5421308004

## Job description

In the late 1960s, Bell Labs was grappling with a large project: an unwieldy operating system called Multics. It was too complex, too slow, and ultimately Bell withdrew. A small group of researchers, led by Ken Thompson and Dennis Ritchie, decided to start over—not with grand designs, but with simplicity at the core.

They aimed for function over perfection and were deliberate in their collaboration. Engineers shared ideas as rough drafts, circulated them early, and refined them through iteration.

From this came Unix. It wasn't about working harder or sacrificing more - it was about getting ideas out quickly and leveraging collective intelligence early in the process.

This is central to how we build at Co–Star: we start with simple solutions, share them early as written docs, and evolve them through real-world feedback.

At Co–Star you’ll help tens of millions of people connect with each other and themselves—through astrology—in real, meaningful ways. We’re looking for a backend engineer who values feedback, who is both fast and deliberate, and who creates systems that let small teams deliver outsized results.

## What you'll do

- Partner closely with product, design, and other engineers to deliver high-quality solutions that align with business priorities. You'll be a true collaborator who helps move the team forward as a unit.
- Break down complex problems to provide insight, technical guidance, and shape scope. You’ll weigh tradeoffs to find the best solution for the business and articulate those points in writing.
- Own delivery and move quickly. We’re looking for someone who eagerly seeks feedback and actively moves the ball forward - who genuinely enjoys getting their code into the world.

## What you'll bring

- 3-7 years of backend development experience. Knowledge of or excitement to learn Haskell.
- You love good documentation and testing. You know well-documented, tested code sets your future-self up for success.
- A sense of ownership over work end-to-end, accountability for results, and supportiveness for your team.
- You’re passionate and pragmatic when problem solving. You focus on outcomes and enjoy solving user problems.
- Strong technical judgment. You can articulate tradeoffs clearly, especially when working with incomplete information or in pre-decision situations.
- You make informed decisions that balance speed with quality and see around corners to anticipate potential challenges.
- Experience with cloud infrastructure (AWS) and databases (we use PostgreSQL).

## What we offer

- Fully covered $0 deductible healthcare + vision, dental, and therapy
- 401(k) + 5% matching
- Unlimited vacation + 2 week company-wide recharge at the end of each year
- Equipment budget
- 12 weeks 100% paid parental leave
- Readings with in-house astrologers
- A competitive total rewards package, including base salary, equity (stock options), and benefits. Our salary and equity ranges are highly competitive within the tech industry and are regularly updated using the most reliable compensation survey data. Offers are crafted based on a candidate’s experience, expertise, location, and internal equity relative to peers. Our target new hire base salary ranges for this role is $159,000-$205,000.

## About Co–Star

## Company Overview
- **One-liner**: Co–Star is a hyper-personalized astrology app that uses NASA data and AI to generate real-time horoscopes, birth charts, and social compatibility tools.
- **Entity Type**: Private (raised $21M in total funding)
- **Headquarters**: New York City, New York, USA
- **Founded**: 2017
- **Founders**: Not publicly listed on provided sources

## Core Business
- **Primary industry/industries**: Astrology, Mobile Apps, Artificial Intelligence, Social Networking
- **Target customers**: B2C; primarily Millennial and Gen Z consumers interested in astrology, self-reflection, and social connection
- **Mission or purpose statement**: "We’re hacking tech, culture, and consciousness to build new practices for self-reflection and deep connection." [costarastrology.com](https://www.costarastrology.com/about/)

## Products & Services
- **Co–Star App**: A hyper-personalized, social astrology app available on iOS. It uses NASA data to generate full birth charts and real-time horoscopes based on the complete positions of the planets, moon, and houses—not just the sun sign. Features include daily horoscopes, compatibility analysis with friends, and social features like top friends for the day and asynchronous messaging. [costarastrology.com](https://www.costarastrology.com/)
- **Email Horoscopes**: Users can sign up to receive daily horoscopes via email. [costarastrology.com](https://www.costarastrology.com/)
- **Natal Chart Tool**: Provides in-depth personality analysis based on the day, time, and place of birth, created in partnership with professional astrologers and AI. [costarastrology.com](https://www.costarastrology.com/natal-chart)

## Market Standing
- **Valuation/Market Cap**: Not disclosed (private company)
- **Key Metric**: Total funding of $21,000,000 raised from investors behind companies like Twitter, Discord, Snap, and Glossier. [greenhouse.io](https://job-boards.greenhouse.io/costar)
- **Notable Investors/Partners**: Backed by investors from companies like Glossier, Twitter, Discord, and Snap. [greenhouse.io](https://job-boards.greenhouse.io/costar) & [costarastrology.com](https://www.costarastrology.com/jobs)
- **Growth Signals**: Five years after launch, someone downloads Co–Star every 5 seconds. The app has been referenced by celebrities like Big Sean, Ariana Grande, and Kevin Durant. It has been Apple's "App of the Day" twice. [costarastrology.com](https://www.costarastrology.com/jobs)

## Competitive Advantages
- **Data Moat**: Uses NASA data and proprietary technology to generate accurate, real-time horoscopes based on the full birth chart (not just the sun sign), differentiating it from generic magazine horoscopes. [costarastrology.com](https://www.costarastrology.com/)
- **AI + Human Insight**: Combines state-of-the-art AI models like GPT-3 with insights from staff poets and professional astrologers to create "hyper-personalized" synthetic text. [costarastrology.com](https://www.costarastrology.com/jobs)
- **Strong Brand & Cultural Relevance**: Has built a distinctive, often-described-as brutally honest tone. The app is deeply integrated into pop culture, with high-profile celebrity endorsements and viral social sharing. [vanityfair.com](https://www.costarastrology.com/jobs)
- **Network Effects**: Social features (friend compatibility, messaging) create a sticky ecosystem that encourages daily engagement and organic growth.

## Strategic Focus
- **Building the Social Layer**: The company is actively building out social features like "top friends for the day," asynchronous messaging, and groups, developed in tandem with practicing group therapists to foster deeper connections. [greenhouse.io](https://job-boards.greenhouse.io/costar)
- **Scaling Reliability**: Focused on increasing app reliability as the user base grows. [greenhouse.io](https://job-boards.greenhouse.io/costar)
- **Developing New Models for Relationships**: Aiming to use technology and astrology to create new ways for humans to relate to themselves and each other. [costarastrology.com](https://www.costarastrology.com/jobs)

## Why Work Here
- **Culture**: Describes itself as "thoughtful, open and tight-knit." The culture emphasizes diversity, inclusion, and cross-functional collaboration—writers work directly with AI models, and designers collaborate with therapists. [costarastrology.com](https://www.costarastrology.com/jobs)
- **Remote/Hybrid Policy**: While based in NYC, the company is open to hiring remote candidates. However, many roles listed on Built In are described as "In-Office," suggesting a hybrid or in-person preference for some positions. [builtin.com](https://builtin.com/company/co-star-0)
- **Notable Perks**:
  - Fully covered $0 deductible healthcare (including therapy, vision, and dental)
  - 401(k) with 5% matching
  - Unlimited vacation + a 2-week company-wide recharge at the end of each year
  - 12 weeks of 100% paid parental leave
  - Equipment budget
  - In-house astrologer readings for all new employees [greenhouse.io](https://job-boards.greenhouse.io/costar)
- **Engineering Culture**: Engineers give presentations on communities they've been a part of. The company offers a $5,000 referral bonus for engineers, product managers, and data scientists. [costarastrology.com](https://www.costarastrology.com/jobs)
- **Hypothesis-Driven Experimentation**: The team uses data to inform decisions, ships MVPs fast, A/B tests everything, and interviews users to validate hypotheses. [costarastrology.com](https://www.costarastrology.com/jobs)

## Sources
1. [costarastrology.com - About Page](https://www.costarastrology.com/about/)
2. [costarastrology.com - Jobs Page](https://www.costarastrology.com/jobs)
3. [costarastrology.com - Homepage](https://www.costarastrology.com/)
4. [costarastrology.com - Natal Chart](https://www.costarastrology.com/natal-chart)
5. [greenhouse.io - Co–Star Careers](https://job-boards.greenhouse.io/costar)
6. [builtin.com - Co-Star Profile](https://builtin.com/company/co-star-0)

## Other roles at Co–Star

- [Junior Operations Associate](https://feeny.ai/job/junior-operations-associate-co-star-new-york-0v73btt3sn7j) — New York, NY
- [Social Media and Brand Creative](https://feeny.ai/job/social-media-and-brand-creative-co-star-remote-xafbv8efdad4)
- [Brand Designer](https://feeny.ai/job/brand-designer-co-star-remote-48075crdr0w8)
- [Writer](https://feeny.ai/job/writer-co-star-new-york-7tfg1gypx487) — New York, NY
- [Product Designer](https://feeny.ai/job/product-designer-co-star-new-york-np1rwe1vs3xj) — New York, NY / San Francisco, CA
- [Senior Product Designer](https://feeny.ai/job/senior-product-designer-co-star-new-york-k5cm8c76wgcq) — New York, NY / San Francisco, CA
- [Don't see your role?](https://feeny.ai/job/don-t-see-your-role-co-star-new-york-nwjj69gw1xes) — New York, NY