Find open senior backend engineering roles at technology companies in the United States, including fully remote US roles. Each finding must be ONE job posting for ONE role, hosted either on the employer's own careers domain or on an applicant tracking system. Accept job-boards.greenhouse.io, boards.greenhouse.io, jobs.lever.co, jobs.ashbyhq.com, myworkdayjobs.com, smartrecruiters.com, apply.workable.com, jobs.jobvite.com, careers.icims.com, darwinbox.in, keka.com, zohorecruit.com, or a company's own /careers/, /jobs/ or /join/ path that carries a role identifier in the URL. MUST-HAVES, every one of them checkable from the posting itself: the role is based in the United States, or is explicitly remote within it; the title is Senior Software Engineer, Senior Backend Engineer, Software Engineer III, Senior Platform Engineer or Member of Technical Staff, OR the posting names an internal level of Google L5, Meta E5, Amazon SDE III or equivalent, OR the requirements ask for 5 or more years of backend experience; The posting must still be open. Reject anything showing 'closed', 'filled', 'position no longer available', 'no longer accepting applications', or a deadline that has passed. The posting must have been published or last updated within the last 21 days. If the page carries no date at all, say so in the summary and rank it below an otherwise identical dated posting rather than assuming it is fresh. Name the primary language and datastore when the posting does (Go, Rust, Java, Kotlin, Python, TypeScript, Postgres, Kafka, Kubernetes). The following RAISE the value of a finding and are NOT requirements: a published compensation band, a named tech stack, the team size, the reporting line, and whether the role is onsite, hybrid or remote. Say which of them are present. Never reject a posting for omitting them: most postings omit compensation, and treating that as disqualifying rejects almost everything. DO NOT SEND: entry-level, new-grad or SDE-II roles; Staff, Senior Staff, Principal or Distinguished roles; engineering-manager, director or architect-without-coding roles; or frontend, mobile, QA, support and solutions-engineering roles. REJECT these domains outright, they are never the employer: naukri.com, instahyre.com, foundit.in, monsterindia.com, hirist.tech, cutshort.io, glassdoor, indeed, ziprecruiter, simplyhired, jooble, talent.com, adzuna, reed.co.uk, totaljobs, cv-library, stepstone, xing, jobs-radar.com, itreferraljobs.in, educativ.net, digitalxnode.com, and any page whose title reads 'ROLE at COMPANY | SITENAME'. Also skip search and category pages (any URL carrying q=, query=, keyword=, search=, page= or offset=, or a path ending at /jobs, /careers, /vacancies or /openings with no role identifier), recruiter and staffing agency pages, LinkedIn profiles of people who already hold the role, 'we are hiring' social posts, salary guides, interview-prep articles, and course or bootcamp adverts. Lead with the company, the exact title, the location or remote policy, and the stack.