Jobs in United States

Backend Api Engineer in United States

534 active opportunities · Updated October 2026

Explore current backend api engineer jobs across United States. Filter by work mode, employment type, experience, department, date posted and distance.

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📍 San Francisco, California, United States· Full-time
✓ Quality checkedCompany trend -80.2%

About the Team API Enterprise Controls is part of the API Infrastructure organization and owns the platform capabilities that help developers, startups, and enterprises adopt the OpenAI API securely and confidently. We build the systems underneath our APIs and developer platform across authentication and identity, service accounts and key management, secure networking, compliance, auditability, observability, and operational controls. Our users are developers and teams running critical applications on OpenAI, and we partner closely with Product, go-to-market, security, and infrastructure teams to turn their most important needs into reliable, intuitive platform capabilities. About the Role We are looking for an exceptional backend software engineer to help define and ship the enterprise capabilities our API Platform needs to scale.; this is a product-engineering role grounded in deep backend systems. You will work across databases, streaming systems, request routing, authentication, and developer-facing APIs while bringing strong product judgment, developer empathy, and attention to the small details that make a platform easier to understand, trust, and operate. You will lead large cross-functional initiatives, work closely with Product and go-to-market teams, engage directly with sophisticated users, and carry ambiguous needs from discovery through design, launch, and iteration. In this role, you will: Own backend product capabilities end to end across authentication and identity, service accounts and key controls, secure networking, compliance, observability, and operational workflows. Partner with Product, go-to-market, security, infrastructure teams, and sophisticated customers to identify needs, shape the roadmap, and lead large cross-functional projects from design through launch. Design developer-facing APIs, system behavior, configuration, error handling, safe defaults, auditing, and notifications with exceptional care for the details that define a great dev

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📍 San Francisco, California, United States· Full-time
✓ Quality checkedCompany trend -80.2%

About the Team API Agents builds the shared agent harness, tools, and infrastructure that turn OpenAI’s frontier models into systems that can reliably complete real work. We carry the capabilities behind Codex into a much broader set of products and workflows across software engineering, research, finance, healthcare, enterprise operations, and more. Our work spans search and connected context, computer use, memory, delegation and multi-agent coordination, and safe execution. Sitting at the intersection of Research, Codex, infrastructure, and applied product teams, we build reusable agent capabilities that compound across the ecosystem. About the Role We are looking for an experienced backend software engineer to build the core systems behind the next generation of agents. You will design reliable services and abstractions that help agents find the right context, use tools and computers, retain knowledge, coordinate over long-running workflows, and take action safely. The role combines deep backend and infrastructure work with strong product judgment, with opportunities to work across agent runtimes, orchestration, search, execution environments, identity and permissions, observability, and evaluations. This is software and systems engineering rather than model training: success comes from strong backend fundamentals, high agency, and the ability to turn fast-moving research capabilities into dependable production primitives. In this role, you will: Design, build, and operate the shared agent harness and backend infrastructure that power long-running, high-value workflows across OpenAI and third-party products. Build reusable capabilities across search and connected context, computer use, memory, tool execution, delegation, subagents, and multi-agent orchestration. Establish the foundations agents need to operate safely in production, including secure execution environments, identity and permissions, observability, evaluations, reliability, and cost and latency effi

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📍 San Francisco, California, United States· Full-time
✓ Quality checkedCompany trend -80.2%

About the Team OpenAI’s API Multicloud team is responsible for extending OpenAI’s API platform into strategic cloud environments, starting with AWS . The team’s mission is to distribute OpenAI’s API broadly and safely by enabling key API technologies in cloud-native environments, in close partnership with Amazon and internal teams across Codex, Research, Safety Systems, and Applied. The team is focused on bringing core developer and enterprise capabilities into cloud-native environments, including cloud-hosted Codex, model customization / post-training as a service, and new stateful runtime environments for agentic workloads. This work sits at the intersection of production ML systems, developer platforms, model behavior, and large-scale infrastructure. About the Role We’re looking for a backend engineer who can quickly understand OpenAI’s models, products, and systems, then adapt first-party deployments for other cloud platforms. You’ll build backend services, APIs, SDK integrations, authentication flows, and cloud service infrastructure that let developers use OpenAI capabilities in the cloud environments where they already build. This role involves working across teams, sometimes embedded with partner product groups, to ship products quickly and across multiple platforms at the same time. It’s a strong fit for engineers who have built developer tools, especially AI-powered tools, communicate clearly across technical boundaries, and can shape architectures that support different deployment models; experience building cloud services is a strong plus. In this role, you will: Build backend and infrastructure systems that extend OpenAI’s API platform into cloud-native environments, like AWS. Design and ship cloud-contained products that allow customers to use OpenAI capabilities while keeping workloads and data within cloud environments. Help stand up cloud-hosted Codex experiences powered by the OpenAI Responses API. Build the infrastructure and runtime abstractions

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📍 San Francisco, California, United States· Full-time· Remote
✓ Quality checkedCompany trend -80.2%

About the Team OpenAI's mission is to ensure that artificial general intelligence (AGI) benefits all of humanity. The API Platform turns frontier research into reliable capabilities that developers use to build transformative products and services for people around the world. API Safety's goal is to ensure safe deployment of frontier models in the API. We design APIs and systems that help developers share usage context, understand safety events, and apply safeguards tailored to the risk profile of the applications they are building. This work is critical to our frontier model launches and partners closely with teams across API, Integrity, and Safety Research. About the Role We're looking for product-minded software engineers to join a team that is addressing emerging risks at the frontier of model development while building novel solutions for real-world AI deployment. The day-to-day work ranges from solving production challenges to designing new product experiences and safeguards. The right candidate is comfortable balancing tradeoffs across developer experience, latency, reliability, and risk. In this role, you will: Design and build dashboards and APIs for safety controls and customer-facing observability. Develop scalable systems that extend trusted safety capabilities to new use cases, customers, and deployment environments. Partner with Safety Research and Integrity to build safeguards that mitigate emerging risks. Be responsible for the availability, latency, and scalability of safeguards across high-volume API traffic. Own projects from technical design and implementation through launch and ongoing iteration, while raising the team’s engineering standards Your background might look something like: 7+ years of professional experience, excluding internships, in backend, infrastructure, platform, or product engineering roles. A track record of designing, building, and operating production backend services, developer-facing APIs, or distributed systems. Strong s

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📍 San Francisco Bay Area, California, United States· Full-time
✓ High-confidence listingCompany trend -100%

$135K – $300K/yr

Quick readStrong listing-quality and freshness signals

About Ema Ema is building the world’s leading Agentic AI platform to transform enterprise productivity. We enable organizations to delegate repetitive tasks to Ema, the Universal AI Employee, delivering 10x gains in workforce efficiency, across functions. Founded by former executives from Google, Coinbase, Flipkart, and Okta, our team includes engineers from premier tech companies and graduates of Stanford, MIT, UC Berkeley, CMU, and IITs. We are backed by industry leading investors including Accel, Naspers/Prosus, Section32, and angels like Sheryl Sandberg and Dustin Moskovitz. Headquartered in Silicon Valley and with offices in London, Bangalore and Vancouver, Ema is at the frontier of what Agentic AI can do in production — we ship real systems that run real business processes at scale. Who are you? We are seeking an experienced Enterprise Software Engineer to join the Ema team. As an Enterprise Software Engineer, you will be responsible for designing, developing, and maintaining our enterprise software applications. You will work with a cross-functional team of product managers, designers, and developers to deliver high-quality software solutions that meet the needs of our enterprise clients. The ideal candidate has experience building products across the stack and a firm understanding of web frameworks, APIs, databases, and multiple back-end languages. Most importantly, you are excited to be part of a mission-oriented, fast-paced, high-growth startup that can create a lasting impact. You will: Develop and maintain enterprise software applications, including API, data, application, and service development Write clean, efficient, and maintainable code by employing test-driven development process. Build scalable and reliable back-end systems using languages like Go and Python Develop and maintain APIs using REST or GraphQL Integrate multiple enterprise applications and services using a scalable framework like FastAPI Build and maintain data schema using PostgreSQL,

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📍 San Francisco Bay Area, California, United States· Full-time
✓ High-confidence listingCompany trend -100%

$135K – $200K/yr

Quick readStrong listing-quality and freshness signals

About Ema Ema is building the world’s leading Agentic AI platform to transform enterprise productivity. We enable organizations to delegate repetitive tasks to Ema, the Universal AI Employee, delivering 10x gains in workforce efficiency, across functions. Founded by former executives from Google, Coinbase, Flipkart, and Okta, our team includes engineers from premier tech companies and graduates of Stanford, MIT, UC Berkeley, CMU, and IITs. We are backed by industry leading investors including Accel, Naspers/Prosus, Section32, and angels like Sheryl Sandberg and Dustin Moskovitz. Headquartered in Silicon Valley and with offices in London, Bangalore and Vancouver, Ema is at the frontier of what Agentic AI can do in production — we ship real systems that run real business processes at scale. Who are you? We are seeking a Software Engineer to join the Ema team. You are passionate about designing and developing maintainable software applications. You are a creative problem solver who thrives in ambiguity and can make abstract problems concrete. Most importantly, you are excited to be part of a mission-oriented, fast-paced, high-growth startup that can create a lasting impact. You will: Develop and maintain enterprise software applications, including API, data, application, and service development Write clean, efficient, and maintainable code by employing a test-driven development process. Build scalable and reliable back-end systems using languages like Go and Python Develop and maintain APIs using REST and gRPC Build and maintain scalable and extensible data schemas using PostgreSQL, Clickhouse, etc. Contribute to front-end interfaces using HTML, CSS, and JavaScript frameworks such as React or Angular Ensure that applications are secure and adhere to industry best practices Continuously improve software development processes and practices Ideally, you'd have: Bachelor's degree in Computer Science or related field. At least 4 years of relevant work experience. Solid back

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📍 New York, NY, United States
✓ Quality checkedCompany trend +310%

Become a part of our caring community Most AI engineering jobs are a thin wrapper around a model API. This role is different. We build the platform that transforms millions of clinical documents into trusted, actionable data. Our systems use large language models (LLMs) to read medical records, extract structured facts, answer complex questions with citations back to the source document, and route ambiguous cases to human experts for review. Our users make decisions that impact real healthcare outcomes, so “good enough” is not good enough. Building AI systems that are accurate, reliable, auditable, and scalable is at the core of this role. As a Senior AI Applied Engineer, you will design, build, deploy, and operate production AI systems used at scale within one of the largest health insurers in the United States. You will own solutions end-to-end, from user experience and APIs to model orchestration, evaluation frameworks, infrastructure, and production operations. Why Join Us Build production AI systems where LLMs are in the critical path, not just demos or proofs of concept. Work on extraction, retrieval, agentic workflows, and human-review systems that process real healthcare data at scale. Own projects end-to-end across frontend, backend, AI orchestration, infrastructure, deployment, and operations. Solve challenging problems around accuracy, explainability, traceability, and reliability in regulated environments. Ship quickly in a small, high-impact team that embraces AI-assisted development and rigorous quality standards. Build systems that continuously improve through expert feedback, evaluations, and human-in-the-loop workflows. Key Responsibilities Design, develop, and deploy full-stack AI-powered application

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📍 Atlanta, Georgia, United States· Full-time
✓ High-confidence listing

From $139.7K/yr

Quick readStrong listing-quality and freshness signals

Strength in Trust OneTrust’s mission is to enable innovation through the responsible use of data and AI. We believe that ensuring data is trusted shouldn’t slow teams down—it should accelerate what’s possible. This led us to develop the first technology platform for responsible data use in 2016. Today, with AI representing the latest and most impactful expansion of data yet, OneTrust is once again redefining what responsible innovation looks like. OneTrust, the AI‑Ready Governance Platform™, unifies regulatory intelligence, automation, and connected governance workflows so businesses can continue to move at the speed of AI while ensuring good governance to prevent data misuse at scale. Trusted by thousands of organizations worldwide, OneTrust is shaping the future where trusted data becomes a transformative force for business and society. The Challenge We’re looking for a Staff Software Engineer with a passion for solving problems to join our agile AI Governance team at OneTrust. Staff Software Engineers are responsible for developing, contributing to decisions related to design and architecture of new frontend and/or backend features while supporting existing development efforts for our industry-leading platform. Your Mission Development Support development of Java microservices/Libraries while integrating with Jira, Jira Service Management, Slack, Microsoft Teams, SaaS providers, and AI solutions such as Claude Code, ChatGPT/Codex, and Cursor for OneTrust’s AI Governance product. It will involve the designing, development, and unit testing of applications deployed to MS Azure with cloud application architecture using Core Java, REST, and the Spring ecosystem. Contribute to the design of reusable integration patterns, API contracts, authentication, error handling, and data translation across external systems. Help evolve the AI Governance registry and integration ca

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📍 San Francisco, California, United States· Full-time
✓ Quality checkedCompany trend -80.2%

About the Team OpenAI's research training infrastructure powers how our frontier models are trained and evaluated. The Simulation team sits at the intersection between the agentic harness that powers OpenAI's products and the research infrastructure where GPT-next is trained, ensuring that our model's training environment is as realistic as possible. This team owns the integration layer that connects our production harness capabilities into the training stack. The work is highly cross-functional and high leverage: researchers depend on it to run experiments and evaluations reliably as well as to develop the next generation of harness capabilities. Failures in this surface can materially affect training velocity and correctness. About the Role We're looking for a Principal Software Engineer to lead the architecture and evolution of the Simulation Platform. You'll own a critical interface between research and engineering, building the systems, APIs, and operational patterns that let researchers use agentic coding infrastructure safely and effectively in training environments. This role is ideal for a senior backend or infrastructure engineer with strong technical judgment, product sense for highly technical users, and the ability to drive execution across multiple teams. The highest-leverage work is building robust infrastructure that supports and accelerates research without compromising engineering quality. In this role, you will Design, build, and evolve the integration between the Codex harness that powers OpenAI's products and research training infrastructure used for training GPT-next Build a platform for our LLMs to train and be evaluated in simulated environments that mimic their deployment setting as closely as possible, on every axis: agentic harness, compute substrate, timing, tools, data sources, humans in the loop, and more Own major integration surfaces end-to-end, from architecture and API design through rollout, operations, and long-term maintenance Bu

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📍 San Francisco, California, United States· Full-time
✓ Quality checkedCompany trend -80.2%

About the Team The Cloud Agents team builds product infrastructure for long-running agents in the cloud: orchestration, sandboxing and isolation, secure environment connectivity, secrets and identity, observability, reliability, and cost controls. These agents securely connect to diverse developer and customer environments and use tools to accomplish goals. We partner closely with product, research, and infrastructure teams to turn agentic capabilities into dependable platforms for OpenAI products and developers building on OpenAI. About the Role We are looking for an experienced software engineer to help build and scale our cloud agent platform. You will design and operate systems for orchestrating agents at scale. You will work closely with product engineers on ChatGPT, API, and Codex to define the right abstractions and enable them to ship products quickly. Strong backend or infrastructure experience is important; experience with Python, Rust, distributed systems, cloud infrastructure, or product platforms is especially helpful. In this role, you will: Design and scale the orchestration, sandboxing and storage systems that run agentic workloads for Codex, ChatGPT, and the OpenAI API. Partner with product engineers to build a platform that enables them to ship quickly and turn feedback into robust abstractions. Improve reliability, security, performance, and cost efficiency for long-running agents. Deploy services that can operate across different environments and clouds. Your background might look something like: 9+ years of professional engineering experience, excluding internships, in relevant roles at technology and product-driven companies. Experience leading large-scale backend, platform, or infrastructure projects from ambiguous problem statements to production systems. Proficiency in one or more backend languages such as Python, Go, Rust, TypeScript, or similar, and the ability to move across service, platform, and product boundaries. Strong understanding

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📍 Dallas 8000 Frankford Road, United States
✓ Quality checkedCompany trend +340.2%

We’re building a world of health around every individual — shaping a more connected, convenient and compassionate health experience. At CVS Health®, you’ll be surrounded by passionate colleagues who care deeply, innovate with purpose, hold ourselves accountable and prioritize safety and quality in everything we do. Join us and be part of something bigger – helping to simplify health care one person, one family and one community at a time. Position Summary We are seeking a highly experienced Principal / Director-level Full-Stack Software Development Engineer to join our Digital Caremark organization and lead the architecture, design, and delivery of next-generation digital solutions. This role spans AI-enabled applications, scalable digital platforms, and enterprise integrations that power critical healthcare and pharmacy experiences. This is a senior technical leadership role for a hands-on engineer who can operate across the full stack—from intuitive front-end applications to resilient backend services—while setting architectural direction, influencing engineering standards, and mentoring teams. The ideal candidate combines deep technical expertise, platform thinking, and strong collaboration skills to build secure, scalable, API-first solutions in a highly regulated environment. Key Responsibilities: Architecture & System Design • Define and drive architecture for large-scale distributed systems and digital platforms • Lead design reviews and set architecture standards and best practices • Champion API-first, microservices, and event-driven architecture patterns • Ensure systems meet scalability, reliability, security, and compliance requirements • Balance performance, cost, and speed in technical decision-making Fu

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📍 New York, New York, United States· Full-time
✓ High-confidence listingCompany trend -100%

$225K – $300K/yr

Quick readStrong listing-quality and freshness signals

Salary range: $225k - $300k | Equity: 0.15% - 0.35% | In-Person: NYC About Datalab Datalab trains models that read documents reliably at scale. The world's most important information is trapped in PDFs, scans, and files that can't easily be parsed, and getting it out correctly matters. From frontier AI labs processing training data to Fortune 500s like Siemens extracting decades of engineering records, Datalab is where businesses turn to when extraction has to be right. We’re at an 8-figure run rate with a team of 7. Anthropic is a customer. And we have hundreds more across FAANG, frontier AI labs, healthcare, finance, government, and legal. Our tools, Chandra, Surya, Marker, and Lift, have 70,000+ GitHub stars and broad developer mindshare. We're backed by founding members of OpenAI, FAIR, and Hugging Face. Role Overview We’re looking for a fullstack engineer who wants to build the interfaces, tools, and infrastructure that help developers and enterprises use our models. You’ll work across the stack to shape how people interact with OCR, extraction, and document-understanding systems. That includes building core inference workflows, creating intuitive UI for complex parsing tasks, and improving the developer experience across our open-source repos and API. This is a high-ownership role that blends engineering, product thinking, and community engagement. You will work closely with the founders and the rest of the team to ship features, improve performance, and make our technology accessible to a global community of builders. As a small and fast-moving team, roles are fluid. You should enjoy working across backend, frontend, performance, and user-facing surfaces. Your work will directly influence how teams evaluate and deploy our models. Day to day, you will: Ship features to our open source repos, API, and internal tooling. Design and build frontend features that make document parsing more interactive and understandable. Optimize inference performance and improve th

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📍 San Francisco, California, United States· Full-time
✓ Quality checkedCompany trend -80.2%

About the Team The Plugin Developer Platform team builds the APIs, SDKs, and tools that let people extend ChatGPT and Codex. We work on plugins, connectors, the Model Context Protocol (MCP), and interactive apps. We want anyone to be able to turn a useful workflow into a plugin, share it, and have other people use it. A plugin can package instructions and skills with connections to the tools and data it needs. Our work covers plugin creation and publishing, the systems that run plugins across our products, and open standards that developers can build on. About the Role We’re looking for platform-minded engineers who know what it takes to build a platform developers want to use. You’ll work across developer-facing interfaces, APIs, and backend systems. You’ll own features from the first developer conversation through implementation and release. You’ll talk directly with developers, partners, and the open-source community. Their experience will inform the APIs and abstractions you design, the problems you prioritize, and the tradeoffs you make. This role is based in San Francisco. We use a hybrid work model of 3 days in the office per week and offer relocation assistance to new employees. What You’ll Do Design and ship APIs, SDKs, and services that developers use to extend ChatGPT and Codex. Make plugins easier to create, test, publish, update, and share. Improve compatibility and consistency across ChatGPT and Codex, including interactive app experiences. Contribute to MCP and other open standards, bringing practical developer needs into their design. Work with developers and partners to understand recurring problems and improve the platform, tooling, and documentation. Work with Product, Research, Security, and Trust & Safety on permissions, compatibility, and safe, reliable execution. You Might Thrive Here If You Have built software that other developers use. Your experience might include an open-source project, an API or SDK, a developer platform, internal too

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📍 Foster City, California, United States· Full-time
✓ Quality checkedCompany trend -85.9%

Replit is the agentic software creation platform that enables anyone to build applications using natural language. With millions of users worldwide, Replit is democratizing software development by removing traditional barriers to application creation. Replit is a software creation platform that enables anyone to build applications using natural language. With millions of users worldwide, Replit helps more people build and ship software. About the Team Product Platform builds and owns the shared foundations the rest of Replit is built on: backend infrastructure, connectors, product primitives, and the frontend platform. When these foundations are solid, every other team moves faster. This role goes deep on the frontend platform: the architecture and platform layer behind every core product surface. The work is high-leverage and horizontal, and gives you exposure across the whole of engineering. We are a small, collaborative team that values curiosity and clear thinking over pedigree, and we care more about how you reason and build than the route you took to get here. If you like making other engineers faster, you will fit in here. About The Role As a Product Engineer focusing on the frontend platform , you will own the frontend architecture behind core product experiences: application frameworks, the API and data layer, testing infrastructure, and client performance. The goal is simple: product teams ship quickly and reliably on what you build. The team’s work is guided by a few simple questions: Is our core frontend architecture (frameworks, state, routing, SSR/CSR) sound, consistent, and easy to build on? Is our API and data layer reliable and ergonomic, with clear contracts, sensible error handling, and effective caching? Are user-facing surfaces fast and well-instrumented, with testing infrastructure that keeps them safe to change? Is the codebase easy to navigate, change, and extend, including for AI coding agents? You’ll partner closely with engineering, produc

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📍 San Francisco, California, United States· Full-time
✓ Quality checkedCompany trend -80.2%

About the Team The Codex Web Layer team provides the web-based systems and user experiences for Codex across the entire stack, from the Electron-like application framework that powers the application, to the user-facing in-app browser. About the Role In this role, you will be responsible for designing and implementing infrastructure and features end-to-end for the Codex desktop client application. You will help define what it means to be a hybrid agentic/interactive web browser. The team embodies “full stack” development from the lowest-level OS integration to the highest-level interaction design. This role is based in San Francisco. We use a hybrid work model of 3 days in the office per week and offer relocation assistance to new employees. In this role you will: Partner closely with product and design to conceive, design, and build features for Codex web browsing features on macOS and Windows. This role will focus mostly on the backend C++ layer and Chromium, but many features cross the full stack including some TypeScript. Partner with the wider Codex team to deliver a high-performance, stable, and secure application platform for client development. This includes API design and implementation (mostly in C++) and the infrastructure that supports deploying it (in Python, TypeScript, and agentic skills). Work with a small, experienced team of engineers on this critical and rapidly growing product. You might thrive in this role if you: Have significant experience building technically complex features end-to-end. Are a strong C++ developer, especially with experience in browser environments like Chromium and Electron. Since this role is more backend focused, general knowledge of web development and TypeScript is helpful but not required. Thrive in a fast-paced, ambiguous environment. Communicate clearly and concisely across many different roles in the organization. Are self-directed, identifying important work and executing it end-to-end. About OpenAI OpenAI is an AI

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