Duolingo | Full-time | Multiple roles | $177K-$300K | NY and Pittsburgh | ONSITE

Our mission is to develop the best education in the world and make it universally accessible. Our culture is eng-driven, friendly, and very data-driven thanks to our large userbase. More info about working as an engineer at Duolingo here: https://www.youtube.com/watch?v=WThT8sufdBE

Tech stack: (frontends) Swift/Kotlin/TypeScript, (backend) Python/Kotlin/Postgres/Dynamo, (infra) AWS/k8s/Terraform.

We're always hiring for engineers. A few roles below:

Senior Engineering Manager, Monetization: https://careers.duolingo.com/jobs/8414653002

Senior Android Engineer: https://careers.duolingo.com/jobs/8217266002

Engineering Manager, Chess: https://careers.duolingo.com/jobs/8385137002

Senior iOS Software Engineer: https://careers.duolingo.com/jobs/8318257002

Base salary: $200K-300K for Senior Eng Manager, $177K-$240K for the others (+equity).

Perks: free lunch, 2-week winter break + 20 days of flexible time off.

Fullstory | Remote (US), Atlanta, London, Bogotá, Czechia | https://www.fullstory.com/

Fullstory provides privacy-preserving session replay and analytics for websites and mobile apps. Our session replays are nothing short of magical - they look almost like a video of the user's screen (with private details redacted) - and the combination with analytics creates eye-opening insights.

Remote (US):

* Senior Software Engineer, Android - $160~170k - Java, Rust, Kotlin, Compose Multiplatform - https://www.fullstory.com/careers/jobs/3be8b5f8-b05c-4221-b9...

* Senior Software Engineer, iOS - $160~170k - Objective-C, Swift, SwiftUI - https://www.fullstory.com/careers/jobs/1c9234a4-af67-428d-91...

Atlanta, USA (1 day per week in office):

* Software Engineer, Digital Experience Analytics - Go, TypeScript, GCP - https://www.fullstory.com/careers/jobs/a786962d-68c1-48fa-8b...

* Software Engineer, Subtext - AI agents, Go, TypeScript - https://www.fullstory.com/careers/jobs/073bfc41-0ac6-4e59-a5...

We have additional engineering and product design roles open in Colombia and Czechia as well as other roles in product management, sales, HR, support, and solutions in the US and UK. See the full list at https://www.fullstory.com/careers?ashby_jid=bce3fcba-6b80-43...

For US roles, you can expect regular raises & bonuses, equity, and benefits including: health insurance, 401k matching (Vanguard), annual learning stipend, unlimited PTO, parental leave, and more. I take about 4-5 weeks vacation a year, in addition to ~3 weeks worth of company holidays (federal holidays + the week of Christmas to New Years.)

Folks in other countries can also expect a strong benefits package, but I'm not as versed on the details.

Additionally, you get a 5-week sabbatical after 5 years of employment - I took mine about a year ago, and it was fantastic.

To apply, please submit your info on the website, and our recruiting team will get in touch with you. If you have questions, feel free to reply here or contact me directly. (I'm an engineer on the iOS team, but I'll do my best to answer questions.)

LiveKit | Remote | [Livekit.io](http://livekit.io/) | VoiceAI | webRTC | Real-time communications

LiveKit is defining a new paradigm for now applications are built by providing the framework and network infrastructure for voice, video, and physical AI.

Hiring:

>> Senior Software Engineer, Agent Platform: https://jobs.ashbyhq.com/livekit/f152aa9f-981c-4661-99d3-683...

>> Senior Software Engineer, Agents:https://jobs.ashbyhq.com/livekit/1757f49e-7e19-4c45-85f7-e46...

>> Senior SDK Engineer, Android:https://jobs.ashbyhq.com/livekit/62076f79-698c-426e-b4fa-8e1...

What we are looking for: Builders!!!!

>Passion for building something truly impactful

>>Remote company, first principles, global presence!

Co-founders:

Russ d'Sa, CEO and Cofounder: https://www.linkedin.com/in/russelldsa/

David Zhao, CTO and Cofounder:https://www.linkedin.com/in/davidzhao/

EnsoData | Mobile Engineer (React Native/Typescript) | Full-time | Hybrid (Madison, WI) or Remote (US)

EnsoData strives to make healthcare more accurate, efficient, and affordable through waveform artificial intelligence (AI) technology. Using AI and machine learning, our software analyzes billions of data points collected from sensors placed throughout the human body.

We are seeking a mobile engineer who is passionate about making healthcare better and has experience building React Native Typescript apps.

Looking for 5+ years full time experience working with a team building React Native Typescript apps for iOS and Android.

Actively hiring - please apply at https://apply.workable.com/ensodata/j/8E07E794DF/ - we would love to hear from you!

At CloudX (https://cloudx.io) we’re building a new supply-side advertising platform for mobile publishers. Yes, it's ads, and yes, there's AI involved, so stop reading here if that's not interesting to you.

It's a gnarly infra problem with huge scale, combined with an interesting product space that we think legitimately benefits from tasteful AI automation. We're doing cool things with Nitro Enclaves to prove that our auctions are fair. And our founding team have done this before with great success, first at MoPub (sold to Twitter) and MAX (sold to AppLovin).

We're hiring (all remote) for:

- Senior Fullstack Engineer https://jobs.gem.com/cloudx/am9icG9zdDogum5THF3fORqb1eEupFQx

- Senior Infrastructure Engineer https://jobs.gem.com/cloudx/am9icG9zdDo4vl4A1sEcc7sDQf8ZYiqR

- Senior Android SDK Engineer https://jobs.gem.com/cloudx/am9icG9zdDqPAWu1cxr3PmEuuTIdliI6

- Senior iOS SDK Engineer https://jobs.gem.com/cloudx/am9icG9zdDpOy3Qmt1fLsOu4gKwtwWTz

Our philosophy is to keep the team small, well-paid, and productive. We deploy every day and our monorepo CI suite takes about a minute to pass.

The best way to apply is directly through those jobs pages. I got so much direct email spam the last time I posted here, I'm afraid I have to ask you not to contact me directly about this role. If you're a real HN reader you're always welcome to contact me with any questions or concerns, but please do not just apply by sending me an email.

Any other hiring managers seeing an incredible amount of fake applicants?

SuperEgo Health | REMOTE | Multiple locations | INTERN

Mobile App Development & Design Engineer Intern (Cross-Platform iOS & Android)

Stipend ₹45,000 per month or equivalent (full-time internship/contract)

Duration: 3–6 months

SuperEgo Health is a healthcare product studio building consumer-facing products across healthcare, AI, and wellness.

We operate with small, senior teams and a strong bias toward shipping. We are hiring a Mobile App Development & Design Engineer Intern in South Asia and South-East Asia to design, build, and ship cross-platform iOS and Android applications used by real users. You should be comfortable with topics and discussions involving consumer healthcare related needs.

Required Skills & Qualifications:

- Strong experience with Flutter (React Native acceptable, Flutter preferred)

- Ability to design clean, usable mobile UI independently

- Solid understanding of mobile architecture and state management

- Experience consuming web and REST APIs

- Comfortable working with ambiguity and minimal specifications

- Strong ownership, independence, and execution speed

- Proficiency with Git and remote collaboration

- Clear written and spoken English

- Good design judgment and an eye for polished UI/UX

- (Optional) Access to BYOD for iOS development (Mac + iPhone/iPad for local builds and testing)

Please email the following to talent@superego.health:

- Résumé or LinkedIn profile

- (Optional) GitHub and/or app portfolio

- A short note describing a feature you built independently

This is a hands-on, high-ownership role. You will be expected to own features end-to-end—from idea and UI decisions to implementation, polish, and release. You will ship production features.

Expected 5–6 hours of availability with Pacific Time.

Core collaboration, planning, and reviews happen during PST hours

Radar Labs | Software Engineers (SRE, data platform, backend, full-stack, mobile) | Remote (US), NYC | Full Time | https://radar.com

- Radar is the geo-location dev tool

- Doing 1B+ API calls per day

- Our main languages are Rust and TypeScript, we also use mobile and offline pipeline languages (Python, Scala, and Terraform).

- We're based in NYC with our HQ in Union Square and remote friendly (US)

Interesting things we're working on:

- HorizonDB, our Geospatial database written in Rust

- Precise indoor location more accurate than iOS and Android leveraging Ultra-Wideband, other mobile sensors and ML.

- Extracting raw map data from satellite maps and the web leveraging ML and AI

- Anomaly detection to identify spoofed locations

- Mobile infrastructure that automatically configures itself optimizing battery-life and location accuracy for different use-cases over time

- Multi-Region AWS K8s deployment, 99.99%+ availability

- Frontend tools to visualize and debug location data at scale

Check out our jobs page here: https://radar.com/jobs#jobs If you have any questions, feel free to reply here or you can e-mail me at tim@radar.com

BitRipple | USA | Full Time | Remote - Prefer domestic USA but open to Non-Restricted Countries

We are hiring two Developer positions: - Senior Software Engineer: Network layer communication optimizations - Senior Software Engineer: GPU porting / RDMA / NCCL / NIXL layer development

We are a deep-tech company building the next generation network communication layer for AI, squeezing out GPU idle time during LLM training with accelerated RDMA communication across clusters. If you love deep systems work and high-performance networking, you will fit right in.

We also service many other networking related industries like mobility, satellite, aerospace, atmospheric optical, VPN, SD-WAN and defense.

- What you’ll do - Design and implement high-throughput, low-latency transport and flow-control logic (think TCP/QUIC/UDP, congestion control, pacing) but next level. Optimize end-to-end performance (CPU/GPU/IO), and ship results that move real workloads.

- What you bring - Proficient in C, C++, Rust Strong grasp of networking transport protocols & flow control concepts. Solid math foundation. You understand memory management, concurrency, throughput and efficiency at scale.

- Nice to have - Mobile (Android/iOS) development knowledge. GPU porting experience. NCCL / NIXL / DPDK integration experience. RDMA/RoCEv2/Infiniband/NVLink knowledge . FEC/erasure coding knowledge.

Interested? Send your resume to: work@bitripple.com You will be talking directly with: Mike Luby, CTO: https://www.linkedin.com/in/michaelluby/ or myself Scott Brown, CEO: https://www.linkedin.com/in/scott-k-brown/

Puma.tech | Remote-first with PST overlap | iOS/MacOS, Android, Ai/ML, Growth | https://puma.tech

Hi all, I’m Yuriy, founder of Puma.tech. Previously worked as software engineer & developer advocate at Cloudant (YC S08, Acq. by IBM), Meteor (YC S11), Parse (YC S11, Facebook/Meta), and explored AI/ML (computer vision for self-driving cars).

We have two products:

1. Puma Browser (iOS & Android) – browser with built in LLMs & Wallets. Private by design.

2. PumaAI app for Mac – ChatGPT/Atlas, but with ability to pick different model providers and fall-back to local-first ones for data privacy.

Open Roles: Eng (iOS/MacOS, Android, Ai/ML, Browser Extensions), Based Social Media Intern; Internships: Eng, Design, Growth

We’ve raised a few rounds from some of the best builders in crypto and ai:

Protocol Labs (YC S14), Chris Larsen (Ripple), Anatoly Yakovenko (Solana), Illia Polosukhin (NEAR Protocol), Sridhar Ramaswamy (Snowflake CEO, Neeva, Greylock), Jason Warner (poolside.ai, ex-GitHub CTO), Don Ho (Orange DAO, Quantstamp W18), Evil Rabbit (Vercel), John Phamous (SF Compute) and other amazing builders.

How to Apply: email careers+hn [at] puma.tech with your GitHub, a note on what you're most proud of building and what you'd like to build next.

Thank you!

AREO | Remote (EU) | Full-Time | Equity | Roles: [Engineering Manager (Ruby on Rails), Lead Product Engineer (Ruby on Rails), Senior Android Developer]

My name is Marius and I am the CTO at AREO (https://goareo.com/).

AREO, founded in January 2023 by a team with 20+ years of combined experience in retail and startups, is a young startup specializing in developing innovative solutions for supermarkets and grocery retail stores. Our cutting-edge B2B SaaS platform optimizes workflows for employees by providing real-time access to inventory, product information, and customer inquiries. We serve large supermarket chains in Germany and across the EU.

About a year ago we brought a backend developer on board through "HN - Who is hiring" and are now seeking a Lead Product Engineer / Engineering Manager and a Senior Android Developer with a minimum of 8 years of experience (preferably in startups) as we just closed another 1M+ ARR contract with a major retail chain and are growing quickly.

For the Product Engineer / Engineering Manager (but not the Android Developer) role professional knowledge of German is highly preferred.

If you're passionate about building innovative retail products from scratch, these roles are for you.

Backend Stack: Ruby / Rails (8.x), StimulusJS / Hotwire / Turbo, AlpineJS, Postgres, Docker, DigitalOcean, OpenAPI, LLMs

Mobile Stack: Kotlin, Room, Jetpack Compose, Hilt Perks: Fully remote roles (Europe), work where you are most productive, sizeable equity in a rapidly growing company, flat hierarchies, no-ego work environment, work in a lean but highly experienced team

Apply here: marius[at]goareo.com and mention “HN - Who is hiring?” and the role you are applying for in the subject.

MixRank (YC S11) | Software Engineers | 100% REMOTE (Global) | Full-Time MixRank processes petabytes of data every month from web crawling. We have hundreds of customers using our data products including Google, Amazon, Facebook, Intel, and Adobe, across industries including Finance, Recruiting, Sales, Marketing, and Security. We’re a fully-remote company with a global footprint in over 20 countries. We're growing, profitable, employee-owned, no dependence on outside funding. Applicants from all geographies and backgrounds are welcome. We are looking for passionate individuals for whom programming is not just a job but it’s something they love to do. We're obsessed with computers, programming, big data, databases, compilers, hardware, math, data science, and the internet. Does this sound like you? Please apply to join our team.

Our code base is very friendly to new contributors. You'll have a fully-functional development environment within hours (fully automated) and be pushing commits on your first day. Deployments to production happen multiple times per day and finish in less than 2 minutes. Effectively all of our codebase is written in Python, Rust, SQL, Javascript/TypeScript, and Nix. The core technologies you'll need familiarity with to be productive are Python, PostgreSQL, Linux, and Git.

We operate at a larger scale than typical startups. We operate two datacenters with high performance servers we've built that are capable of dealing with the volumes of data we process. We've implemented our own distributed file system. We do full-scale web crawls. We download and perform static analysis on the entire universe of Android APKs and iOS IPAs that are published. Unlike a typical startup where you'll spend half of your time in meetings, and the other half fixing bugs from Jira tickets— at MixRank you'll get to challenge yourself with difficult technical problems that will help you to grow as an individual.

We're hiring continuously for the positions below— they aren't singular positions that will close once filled. Our philosophy on hiring is that the candidate is more important than the position. For each new member of the team, we design a custom role and responsibilities that are specialized to their interests. Other companies will come up with a long list of specific requirements for a position with the expectation that you'll exactly replace someone from the team, or that you'll be the perfect tetris piece that satisfies the job requirements decided by a committee. MixRank is more pragmatic: we'll first get excited about having a unique individual on the team, then we'll figure out the best way to accommodate their specific talents.

-- Junior Software Engineer - Remote (Global), Full-Time

We're looking for remote junior engineers that have 0-3 years of professional experience in software, and 5+ years of curiosity exploring computers, programming, and technical hobby projects. This is an open-ended entry role with mentorship and diverse opportunities to work on all areas of our product: databases, distributed systems, infrastructure and tooling, data analysis, machine learning, frontend/backend web development, APIs, data mining, data modeling, and more. To stand out, please highlight what makes you unique: passion for computing, curiosity and side projects, work ethic, niche research, etc.

Ideally you've already graduated, but if you still have one or more years left of school, please feel free to apply anyway, and if you're the right fit for the team we'll figure out a way to accommodate your schedule. https://www.ycombinator.com/companies/mixrank/jobs/Fnwsojk-j... --

Software Engineer - Remote (Global), Full-Time

We're hiring generalist software engineers to work on web applications, data mining, machine learning/data science, data transformation/ETL, data modeling, database scaling, infrastructure, devops, and more. We'll cater the role to whatever subset of these areas match your interests.

Beneficial experience includes PostgreSQL, Python, Rust, Linux, TypeScript, Nix, frontend/backend web development, and data mining.

https://www.ycombinator.com/companies/mixrank/jobs/RXQspen-s...

--

I’m Kiran, Chief of Staff (CoS) at MixRank, a fully remote data startup building go-to-market intelligence. We’re US-incorporated but hire globally, and we’re bringing on new teammates to join a fast-moving team with real ownership and impact.

Sesame | Full-time | SF/NYC/Bellevue | On-site | https://www.sesame.com/

Sesame believes in a future where computers are lifelike - with the ability to see, hear, and collaborate with us in ways that feel natural and human. With this vision, we're designing a new kind of computer, focused on making voice personal agents part of our daily lives. More details from Sequoia: https://www.sequoiacap.com/article/partnering-with-sesame-a-...

Our team brings together founders from Oculus and Ubiquity6, alongside proven leaders from Meta, Google, and Apple, with deep expertise spanning hardware and software.

Open Roles: https://jobs.ashbyhq.com/sesame

- ML Engineers

- Product Designers

- Product Managers

- iOS & Android Engineers

- ML Model Serving Engineer

- Embedded OS Architect

- Mechanical Engineer, Product Design

- Embedded Engineers

- Electrical Engineer

- Audio Systems Engineer

Pushscroll | Full-Stack Mobile Engineer (KMP) | REMOTE (GMT-3 to GMT+4)

We make people do push-ups before they can scroll addictive apps. Our dream is to help replace doomscrolling with exercise, which we verify through camera pose detection.

500k+ downloads, bootstrapped and profitable, very quickly growing.

Looking for someone strong in Kotlin Multiplatform + Compose Multiplatform + Swift/SwiftUI who works independently, uses AI to ship fast, and can implement a pixel-perfect Figma design.

Bonus: Supabase, Amplitude, native Android/iOS knowledge (e.g., Screen Time).

Small team, work directly with founders, long-term role. We’ve got big plans to make Pushscroll the app of the year, and there are a lot of challenging problems to get there.

Reach out: contact@pushscroll.com

Charted Sea | Senior Product & Platform Engineer | REMOTE | Full-time Location: Hong Kong https://chartedsea.com/about

Charted Sea is a small, bootstrapped SaaS company helping customers scrape very complex platforms such as Shopee (a major e-commerce platform in Southeast Asia). We focus on hard technical problems (anti-bot, browser automation, fingerprinting, captcha solving).

We are hiring a senior engineer to take ownership of our core platform: scraper orchestrator, billing & payments, customer dashboard, and parts of our AI-based captcha tooling. This is a hands-on role with real ownership: architectural decisions, setting standards, and gradually mentoring other engineers. The role is very full-stack (infra, backend, frontend).

Stack includes TypeScript (most backend & web), Rust (new backend services, migration in progress), Go (Android scraper), PyTorch (captcha solvers), PostgreSQL, Redis, GitHub Actions, Ansible, Ubuntu Linux, bare-metal Hetzner servers.

We are profitable, demand is growing fast, and engineering bandwidth is the main bottleneck. Team is small (3 engineers), fully remote, mostly async (we expect ~4h overlap with UTC+8).

Compensation: $80k–$120k USD base (depending on experience) + monthly bonus tied to company revenue (10% of net revenue shared with employees).

Apply by emailing marc.plouhinec@chartedsea.com with a short intro and CV/GitHub. I'm the founder and will personally read and reply.