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Software Engineer, Tokens and Prompt Structures

Anthropic· AI Research & Engineering
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Hybrid (San Francisco, CA), Hybrid (New York City, NY)$320k - $405kFull-timePosted 4w ago

About the role

Software Engineer on the Encodings Infra team responsible for maintaining libraries that encode text and multimodal data for Claude, shaping prompt structures, and enabling production-ready experimentation and deployment across pretraining, finetuning, and API layers.

Responsibilities

  • Maintain and improve the encoding libraries used by engineers and researchers across Anthropic
  • Run experiments to determine the optimal way to feed structured data into Claude without confusing it
  • Design data structures and abstractions that shield most of the organization from the details of how encoded data works while enabling “power users”
  • Adapt the encoding libraries to support new research directions as they emerge, and make sure that we can ship these research ideas to production
  • Optimize encoding performance across the systems that depend on these libraries

Qualifications

  • 5+ years of software engineering experience, with meaningful time spent maintaining libraries, SDKs, or developer-facing APIs
  • Familiarity with ML terminology and LLM architecture — enough understanding to work with researchers and interpret experiment results
  • Experience carrying out complex refactors in large codebases
  • Strong communication skills and ability to work closely with researchers and engineers to understand needs
  • Results-oriented with flexibility and impact
  • Willingness to take on tasks outside the job description
  • Care about societal impacts of work

Skills

Required:Encoding libraries maintenancePrompt structuringSystems design for data encoding

Benefits

  • Competitive compensation and benefits
  • Optional equity donation matching
  • Generous vacation and parental leave
  • Flexible working hours
  • Office space for collaboration
  • Visa sponsorship available (with caveats)
Last updated Sep 23, 2026. Interested? Apply on the company site.

About Anthropic

building reliable, interpretable, and steerable AI systems

Anthropic is an AI safety and research company that's working to build reliable, interpretable, and steerable AI systems.

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