krea.ai | Senior Backend Engineer | San Francisco, CA | ONSITE | https://www.krea.ai

krea does AI research & builds AI tools for image generation, video generation, node-based workflows, LoRA training, and more. Small, mostly in-person team with a view of Alcatraz from the office window. Our users range from hobbyists all the way to professional designers at Apple or architects at firms behind The World Trade Center or Burj Khalifa.

We're looking for senior backend engineers. You'd work across our SvelteKit app (Postgres, Redis, Docker, ClickHouse), Python ML inference on GPU clusters, and k8s clusters across multiple cloud and GPU providers.

Some recent projects:

- building canary deploys with cookie-sticky traffic splitting - implementing durable execution for long-running workflows - designing our public API with OpenAPI docs auto-generated from Zod schemas - implementing enterprise-grade authentication, authorization, and permissions - optimizing ML inference for our hosted image generation models

We care way more about first-principles and core engineering skills rather than specific shenanigans around programming languages or particular tooling—knowing a lot about old UNIX principles is a plus though.

You should be comfortable owning things end-to-end. Experience with GPU infra is a plus. Many of us have some kind of creative background, it helps when building tools for creatives but is not a requirement by any means.

To apply, email d+hn@krea.ai (use the +hn suffix to make sure your email is prioritized!)

FusionAuth | Senior Java Engineer, Technical Support Engineer, Account Executive , Solutions Engineer | Varies between REMOTE (in USA, also in Europe but only for the account exec/solutions engineer positions) and ONSITE in Denver, CO, USA, details in each job desc | Salary ranges listed on job req, but for the Senior Java Engineer it is 140k-180k

At FusionAuth, our mission is to make authentication and authorization simple and secure for every developer building web and mobile applications. We want devs to stop worrying about auth and focus on building something awesome. We also recently acquired a fine-grained authorization company ( https://fusionauth.io/blog/fusionauth-acquires-permify ) and are going to be building in that area as well.

There are a lot of companies in the auth space, but we feel like we have something special:

* a unique deployment model (self-host on-prem or in your cloud or run in our cloud)

* A well designed API first approach; one customer compared our APIs to petrichor

* a mature product (the code base is nine+ years old and we've found and fixed a lot of the sharp edges around core login use cases; but don't worry, there are plenty more features to add)

* our CTO is the founder and still writes code

* a full featured free-as-in-beer version which makes the sales cycle easier; prospects often come in having prototyped an integration already

Our core software is commercial. We open source much of our supporting infrastructure. Technologies and standards that you will work with: modern Java, PostgreSQL, Docker, Kubernetes, MySQL, OAuth, SAML, OIDC.

Learn more, including about benefits and salaries, and apply here: https://fusionauth.io/careers/ ( Click/tap the 'View open positions' orange button. )

We're actively hiring, lots of positions. WEX is an international Fintech company. Most positions are being recruited as on-site roles, must be located near or willing to relocate to one of our locations. It's been a good company to work for, I've been there 7 years.

https://careers.wexinc.com/us/en/

Espresso AI | Staff Engineers | NYC ONSITE | Full Tim

We use ML to make data warehouses and spark jobs more efficient. We're hiring staff ML engineers to train models that can understand how much compute a job needs, how it scales to larger machines, whether a machine can run more jobs, and so on; and staff infra engineers to take those models and deploy them on real-world production systems.

If this sounds cool, please email me an intro and a resume: ben [at] espresso [dot] ai

THINKalpha | Senior Frontend Engineer | Remote | Full Time

We're building alphaLENS (https://alphalens.io), a suite of tools for professional market research and trading. Public registration opens in days. You can see our company at https://thinkalpha.io.

Stack: Svelte (migrating from React/Redux), MVVM architecture with signal primitives, class-based models with IoC for cross-platform targeting (web + Electron, mobile later). Heavy emphasis on testing and performance.

Looking for: Someone who thinks about problems in detail. You should be comfortable with OOP in JS, understand reactive primitives at a deeper level than hooks, and be able to operate autonomously on a small team.

If this is you, please reach out to me with your resume and a brief intro: jason [at] thinkalpha [dot] io

Workmind | Senior Backend Engineer | Bangkok, TH | Remote | Full Time

Workmind is a startup that builds AI-powered automation software for franchises and multi-location businesses, and we are growing quickly.

We are hiring 1 - 2 new backend developers to help build new features on our product. We're a small engineering team based in Southeast Asia, and we're looking for engineers with a track record of excellence who can hit the ground running.

View the full job description and application instructions here: https://workmind.cloud/jobs/backend-dev/

Kroo | Product and Integrations SWEs | NYC, Hybrid | Full-Time | $110k - $200k + equity + health benefits

Kroo is building the knowledge platform for construction, an industry that deeply needs more technology solutions. We’ve built a platform that our 30+ enterprise customers use to operate and maintain data connectors, warehousing, and knowledge graphs specific to the nuances of the construction industry (think on-premises systems, archaic APIs, etc.). Our customers, data professionals in the construction industry, use our software to build reporting and run analytics for billions of dollars of jobs.

We're looking for full-stack Product Engineers with 3+ YOE and Integrations Engineers with 1+ YOE. We are a venture-backed, pre-seed stage company with an experienced and hungry team. We’re backed by leading investors in the space and based in Midtown NYC (hybrid). If you’re looking to build in an industry that desperately needs data and AI solutions, apply here!

https://jobs.gusto.com/boards/kroo-70b14610-ea9c-4478-9fc8-5...

Lago | Europe+US | Remote or Hybrid | Full-time |

Open-source usage-based billing (Customers include CoreWeave, Groq, PayPal). YC & FirstMark backed.

Hiring across teams: https://getlago.com/hiring

xAI | London, UK | ONSITE | Full-time | https://x.ai

Our London team is hiring two key roles:

Backend Engineer

Build and scale high-performance production systems powering grok.com and the xAI API. Strong Rust (or C++) required — distributed systems experience a big plus.

→ https://job-boards.greenhouse.io/xai/jobs/4991448007

Developer Experience Engineer

Make the xAI API the ultimate playground for builders and hackers. Craft world-class docs/examples/tools, and engage the dev community. Strong TypeScript full-stack + proven open-source/DevRel experience required.

→ https://job-boards.greenhouse.io/xai/jobs/4985451007

Small, high-ownership team. Competitive comp, meaningful equity, full benefits. Visa sponsorship available. High-agency builders excited about frontier AI — apply above!

CodSpeed | Multiple Positions | On-site (Paris) / Remote (Europe) | Full-time | https://codspeed.io

We’re building the continuous performance optimization platform. We help engineering teams catch performance regressions before they ship, with sub-1% measurement variance. We’re already trusted by teams at Cloudflare, Vercel, Mozilla, Pydantic, and Astral (Ruff, uv).

We’re a small, deeply technical team looking for engineers who want real ownership and the chance to ship end-to-end. Competitive salary, stock options, generous PTO.

Senior Systems Engineer: CPU simulation tooling, language runtime internals (CPython, V8), kernel I/O emulation. C/C++/Rust/Zig.

Senior Full-stack Engineer: React/Next.js, Node.js/TypeScript/GraphQL, GitHub/GitLab integrations, Rust data pipelines.

Senior/Lead AI Engineer: Agent layer, eval methodology, context pipelines, model selection. Python/FastAPI.

Graphic/UI Designer: Visual identity and product experience for a developer tool.

More details at https://careers.codspeed.io. Apply at careers@codspeed.io

AllSpice.io | Remote (US time zones) | Senior / Principal Engineers | Full-time

Think of github but for hardware design. (PCB and Schematics design). Our mission is to bring the same modern workflows that revolutionized software: version control, automation, and collaboration to the hardware world. We are also introducing AI to hardware design!

We work on:

• Parsing complex ECAD formats (Cadence, Altium, etc.).

• Schematic/PCB diffs (not just text).

• Hardware CI pipelines (BOM, DRC, PLM integrations).

• AI-assisted design reviews.

• Scaling a Git-based platform for non-software engineers.

Stack: Go, Python, Rust, Vue/TypeScript, Postgres, AWS, Docker, Terraform (Gitea-based core)

-----------------------------------

Open roles:

• Principal Engineer (Parsing)

• Senior Infra Engineer (Infra)

Looking for engineers who like deep systems problems and high ownership.

Apply: https://www.allspice.io/careers

SF Sauna -- SF Bay Area

Electrical / Power Systems Engineer - Build a battery-integrated sauna heater

Paid contract role, $80 - 150/hr, 15–25 hr initial scope

This is a multi-kW DC system problem (battery pack, resistive heater, contactor, safety logic). The constraint is reaching sauna temps without relying on a 240V wall connection.

We currently generate ~$5k MRR renting saunas in the SF Bay (sfsaunarental.com). We've validated pain-point and demand.

If there’s mutual interest and the prototype goes well, this could extend into deeper collaboration or a more dedicated role.

To apply, email zach (at) sf-sauna (dot) com and include:

A short description of the EE project you're most proud of building from scratch A link (GitHub, project photos, writeup, resume, etc)

Visit sf-sauna.com for more info about the problem space.

Heard | Senior Software Engineer (Full-Stack) | Seattle | HYBRID | Full-time

We just crossed $11M ARR and 5,000 customers -- all therapists and mental health providers who trust us to run their financial back office: bookkeeping, taxes, payroll. Now we're building AI-powered CFO for therapists -- a layer on top of our ledger. Think proactive financial guidance, automated transaction classification, reconciliation, and agentic workflows that collapse hours of bookkeeping.

Stack: TypeScript, Node/Express, React, Postgres, AWS, lots of third-party integrations. You'll work across automation, AI product, and growth depending on what matters most. Apply: https://jobs.lever.co/heard/8d51e41d-b9c5-45fd-b9bc-f2a1c7f0...

Tangled | Distributed systems / Generalist Engineers (Go, Nix) | REMOTE (Global)

Tangled is the next-generation social coding platform. We offer git repository hosting, stacked PRs, Nix-based CI and more. We just raised our €3.8M ($4.5M) seed round[0] to build foundational infrastructure for the future of open source.

Some of the things we're working on:

* a fully revamped CI (spindle v2!) built on micro VMs to allow for faster builds and more choice of build environments

* protocol-level improvements across the board that’ll unlock nifty things like repo migrations across knots, organizations, and more!

* a customizable “mission control” dashboard for your active PRs, issues, and anything else you might want to track

* a migration tool to help you move off GitHub

* all things search: code search, repo search, etc.

* platform and infrastructure performance improvements & more global presence

* Tangled CLI!

We're prioritizing hiring for CI infrastructure, so strong distributed systems experience, Go, Firecracker/virtualization, etc. are what we're looking for. If this sounds interesting, send us an email to team@!

[0]: https://blog.tangled.org/seed

Yuzu Health (yuzu.health, Series A) | Location: New York City (Flatiron) | ONSITE Pitch: Yuzu is not a wrapper, point solution, or integration on top of something. Our platform makes it easy for anyone to create their own health plan from scratch. That means our tech handles everything from the member/HR portals, claims adjudication, invoice automation, member support tools, to even printing and sending out ID cards.

Why: We're truly rebuilding health insurance from the ground up. We currently serve over 1,000 employers, and we're growing extremely fast (like over 10x last year fast)!

Investors: We're well funded with investors like General Catalyst, Chemistry, Anthropic, Lachy Groom, Neo and founders from startups you know like Notion, Brex, Deel, and Mercury.

Roles: We're hiring engineers for in-person work over here at Yuzu's HQ in Union Sq, Flatiron. Primary need is for Fullstack/Product Engineers but we're also looking for a Data Engineer and a Product Designer. Job board here - https://yuzu.health/careers You can check out our office in our recent MTV cribs office tour also - https://www.linkedin.com/feed/update/urn:li:activity:7398820...

I'm Kev, the recruiting lead. Reach out to me directly if interested on kev ( at ) yuzu ( dot ) health

Journalytic | UI Developer (React/TypeScript) | REMOTE (US time zones) | Full-time

Journalytic is an early-stage company building a mission-critical operating system for professional investment teams. We combine behavioral science, structured workflows, and well-crafted software to help hedge funds, family offices, and RIAs make better decisions every day.

We’re a remote team with hubs in Pennsylvania, California, and Seattle. This role is perfect for an engineer who relishes complex technical challenges in a fast-paced startup environment. You’ll be joining a team of passionate A+ players who will support you and challenge you to grow. You won’t be a small cog in a big machine. Your work will have a direct impact on how the world’s best investors operate.

For full details and to apply, visit https://jobs.journalytic.com

Charge Robotics | Multiple Roles | Full-time | Onsite | SF Bay Area

Hi HN! We’re a YC-backed, Series-A startup building robots that build large-scale solar farms.

Check out a video of our first system here! https://youtu.be/ZZ2fP1Y5Z2E

It turns out that construction companies literally can't build solar fast enough, so what we're doing is a crucial part of switching the grid over to renewable generation.

You’ll be a key contributor, helping bring our next generation of mobile solar factory to life.

Come work with us if you love:

* Fast-paced prototype development with software and hardware components

* Making a positive climate impact through your work

* Hacking on massive construction equipment!

Senior Robotics Software Engineer: https://jobs.ashbyhq.com/charge-robotics/b2aa347c-4738-4065-...

Senior Mechanical Engineer: https://jobs.ashbyhq.com/charge-robotics/19133a2e-f262-4f3d-...

Lots more: https://jobs.ashbyhq.com/charge-robotics

Immunera | Principal Machine Learning Engineer | NYC area (hybrid) | Full-time | immunera.ai

Hey! I’m Maxim, cofounder/CEO of Immunera.

We're building blood tests that use gene sequencing and machine learning to help patients with autoimmune disease. Immunera spun out of years of research at Stanford, and our technology has been published in Science and covered by The New York Times.

We're hiring a Principal Machine Learning Engineer to shape the core models and infrastructure that power our blood tests. We are partnering with hospitals to generate training data from real patients for our language models and other biological sequence models.

This is a senior engineering role with significant autonomy at an early-stage, venture-backed startup. We're looking for strong experience building and operating ML systems in production (Python, PyTorch/TensorFlow, cloud platforms). Prior biology or healthcare experience is NOT required; we care much more about your ability to reason about data, models, and systems.

Full JD: https://www.immunera.ai/jobs

Contact: maxim@immunera.ai (subject: “HN ML job”)

We have multiple openings for: QA Engineers, Go Engineers, Full Stack Typescript Engineers (Remote, Europe)

About us: We're a fast-growing, strategy-first software studio. We design, build, and launch products across many verticals. We're fully remote with flexible working hours. Learn more about our company culture at the apply links below!

* Please use "hackernews" as your referral source and I'll flag your CV for priority review with the hiring team! *

ROLE: Quality Assurance Engineer | REMOTE (Central/Eastern Europe) https://careers.gojilabs.com/32205

ROLE: Go Engineer | REMOTE (Central/Eastern Europe) https://careers.gojilabs.com/34031

ROLE: Full Stack Typescript Engineer | REMOTE (Central/Eastern Europe) https://careers.gojilabs.com/31725

New Lantern | https://newlantern.ai | Software engineers (frontend and backend product engineers) | Full time in San Francisco, CA (ONSITE)

New Lantern is building an AI radiology resident—think Cursor for radiologists. Our application integrates the three software tools radiologists use all day [1], together with AI, to create a platform that saves radiologists toil and lets them focus on reading images and finding disease.

We are a series A startup with ~15 engineers (~30 total staff), have live customers generating revenue, several years of runway, and are backed by Benchmark, Anthropic, and other great investors.

We're hiring for several engineering roles. You'll work directly with our founder/CEO, our staff radiologists, and our end users to build a product that radiologists rely on daily. You'll have real ownership and autonomy, and ship meaningful work frequently.

I'm Steve, New Lantern's Head of Engineering. If you're interested or want to learn more, shoot me a note at (my HN username)@newlantern.ai. I've already hired one engineer from HN this year!

[1] a radiology image archive & viewer, a medical report dictation system, and work management system