# SONNET CODE

> Boutique engineering — senior-only team building web, mobile, and AI products for product teams in the US and Latin America. Timezone-aligned, English- and Spanish-fluent.

SONNET CODE is a boutique engineering team building web, mobile, and AI products for product teams in the US and Latin America. Senior engineers, timezone-aligned.

SONNET CODE is a US LLC (New Mexico) with an office in Santo Domingo, Dominican Republic, operating as a boutique engineering practice. The team is distributed across the Americas and aligned to US and Latin American business hours; both are markets we sell into. We take engagements where we know we can deliver and decline the rest — scoping honesty is part of the value.

Two offerings worth noting explicitly because they often get conflated:

- **AI Development** — building AI features into products (LLM apps, RAG, agents, evaluations, fine-tuning).
- **AI Training** — the outlier.ai-style human-in-the-loop offering: RLHF data, SFT demonstrations, red-teaming, model evaluations, and domain experts on tap for frontier AI labs.

Contact: hello@sonnetcode.com

## Key pages

- [Home](https://sonnetcode.com/): Overview of SONNET CODE — services, technologies, and engagement model.
- [About](https://sonnetcode.com/about): Who we are, how we work, and what a boutique engineering engagement looks like.
- [Services](https://sonnetcode.com/services): Full list of services — AI, web, mobile, data, QA, design.
- [Technologies](https://sonnetcode.com/technologies): Languages, frameworks, and platforms we ship production systems in.
- [Industries](https://sonnetcode.com/industries): Regulated and consumer-tech industries we take engagements in.
- [AI Training](https://sonnetcode.com/services/ai-training): Human-in-the-loop offering — RLHF data, SFT demonstrations, red-teaming, evals, domain experts.
- [AI Development](https://sonnetcode.com/services/ai-development): Building AI features into products — LLM apps, RAG, agents, fine-tuning, evaluations.
- [Blog](https://sonnetcode.com/blog): Original essays on engineering practice — architecture, hiring, AI, and delivery.
- [FAQ](https://sonnetcode.com/faq): Direct answers on engagement model, pricing, IP, NDA, onboarding time, and AI tooling.
- [Contact](https://sonnetcode.com/contact): How to reach the team — hello@sonnetcode.com, contact form, and scheduling link.
- [Careers](https://sonnetcode.com/careers): Open roles and how to apply — CV upload goes to the hiring team.

## Flagship services

- [LLM Application Development](https://sonnetcode.com/services/llm-application-development): AI & LLM service — how SONNET CODE delivers LLM Application Development.
- [RAG Systems](https://sonnetcode.com/services/rag-systems): AI & LLM service — how SONNET CODE delivers RAG Systems.
- [AI Agents](https://sonnetcode.com/services/ai-agents): AI & LLM service — how SONNET CODE delivers AI Agents.
- [Fine-tuning & Post-training](https://sonnetcode.com/services/fine-tuning-and-post-training): AI & LLM service — how SONNET CODE delivers Fine-tuning & Post-training.
- [AI Evaluations](https://sonnetcode.com/services/ai-evaluations): AI & LLM service — how SONNET CODE delivers AI Evaluations.
- [AI Development](https://sonnetcode.com/services/ai-development): AI & LLM service — how SONNET CODE delivers AI Development.
- [AI Training](https://sonnetcode.com/services/ai-training): AI & LLM service — how SONNET CODE delivers AI Training.
- [Back-end Development](https://sonnetcode.com/services/back-end-development): Core service — how SONNET CODE delivers Back-end Development.
- [Data Engineering](https://sonnetcode.com/services/data-engineering): Core service — how SONNET CODE delivers Data Engineering.
- [Front-end Development](https://sonnetcode.com/services/front-end-development): Core service — how SONNET CODE delivers Front-end Development.
- [Mobile App Development](https://sonnetcode.com/services/mobile-app-development): Core service — how SONNET CODE delivers Mobile App Development.
- [QA Testing & Automation](https://sonnetcode.com/services/qa-testing-and-automation): Core service — how SONNET CODE delivers QA Testing & Automation.
- [SaaS Development](https://sonnetcode.com/services/saas-development): Core service — how SONNET CODE delivers SaaS Development.
- [Staff Augmentation](https://sonnetcode.com/services/staff-augmentation): Core service — how SONNET CODE delivers Staff Augmentation.
- [Web Development](https://sonnetcode.com/services/web-development): Core service — how SONNET CODE delivers Web Development.

## Industries

- [Finance & Banking](https://sonnetcode.com/industries/finance-and-banking): Regulated industry — engineering engagements for Finance & Banking teams.
- [Insurance](https://sonnetcode.com/industries/insurance): Regulated industry — engineering engagements for Insurance teams.
- [Healthcare](https://sonnetcode.com/industries/healthcare): Regulated industry — engineering engagements for Healthcare teams.
- [Pharmaceuticals](https://sonnetcode.com/industries/pharmaceuticals): Regulated industry — engineering engagements for Pharmaceuticals teams.
- [Government](https://sonnetcode.com/industries/government): Regulated industry — engineering engagements for Government teams.
- [Legal Tech](https://sonnetcode.com/industries/legal-tech): Regulated industry — engineering engagements for Legal Tech teams.
- [Education](https://sonnetcode.com/industries/education): Regulated industry — engineering engagements for Education teams.
- [Telecom](https://sonnetcode.com/industries/telecom): Regulated industry — engineering engagements for Telecom teams.
- [SaaS & Startups](https://sonnetcode.com/industries/saas-and-startups): Consumer & Tech industry — engineering engagements for SaaS & Startups teams.
- [eCommerce & Retail](https://sonnetcode.com/industries/ecommerce-and-retail): Consumer & Tech industry — engineering engagements for eCommerce & Retail teams.
- [Media & Streaming](https://sonnetcode.com/industries/media-and-streaming): Consumer & Tech industry — engineering engagements for Media & Streaming teams.
- [Travel & Hospitality](https://sonnetcode.com/industries/travel-and-hospitality): Consumer & Tech industry — engineering engagements for Travel & Hospitality teams.
- [Logistics](https://sonnetcode.com/industries/logistics): Consumer & Tech industry — engineering engagements for Logistics teams.
- [Energy & Utilities](https://sonnetcode.com/industries/energy-and-utilities): Consumer & Tech industry — engineering engagements for Energy & Utilities teams.
- [Manufacturing](https://sonnetcode.com/industries/manufacturing): Consumer & Tech industry — engineering engagements for Manufacturing teams.
- [AI Labs](https://sonnetcode.com/industries/ai-labs): Consumer & Tech industry — engineering engagements for AI Labs teams.

## Technologies

- [OpenAI API](https://sonnetcode.com/technologies/openai-api): LLM & AI — production systems in OpenAI API.
- [Anthropic API](https://sonnetcode.com/technologies/anthropic-api): LLM & AI — production systems in Anthropic API.
- [Mistral AI](https://sonnetcode.com/technologies/mistral-ai): LLM & AI — production systems in Mistral AI.
- [LangChain](https://sonnetcode.com/technologies/langchain): LLM & AI — production systems in LangChain.
- [LangGraph](https://sonnetcode.com/technologies/langgraph): LLM & AI — production systems in LangGraph.
- [LlamaIndex](https://sonnetcode.com/technologies/llamaindex): LLM & AI — production systems in LlamaIndex.
- [Ollama](https://sonnetcode.com/technologies/ollama): LLM & AI — production systems in Ollama.
- [Hugging Face](https://sonnetcode.com/technologies/hugging-face): LLM & AI — production systems in Hugging Face.
- [vLLM](https://sonnetcode.com/technologies/vllm): LLM & AI — production systems in vLLM.
- [Pinecone](https://sonnetcode.com/technologies/pinecone): LLM & AI — production systems in Pinecone.
- [Weaviate](https://sonnetcode.com/technologies/weaviate): LLM & AI — production systems in Weaviate.
- [pgvector](https://sonnetcode.com/technologies/pgvector): LLM & AI — production systems in pgvector.
- [JavaScript](https://sonnetcode.com/technologies/javascript): Language — production systems in JavaScript.
- [TypeScript](https://sonnetcode.com/technologies/typescript): Language — production systems in TypeScript.
- [Python](https://sonnetcode.com/technologies/python): Language — production systems in Python.
- [Go](https://sonnetcode.com/technologies/go): Language — production systems in Go.
- [Java](https://sonnetcode.com/technologies/java): Language — production systems in Java.
- [C#](https://sonnetcode.com/technologies/csharp): Language — production systems in C#.
- [Rust](https://sonnetcode.com/technologies/rust): Language — production systems in Rust.
- [Ruby](https://sonnetcode.com/technologies/ruby): Language — production systems in Ruby.
- [PHP](https://sonnetcode.com/technologies/php): Language — production systems in PHP.
- [Swift](https://sonnetcode.com/technologies/swift): Language — production systems in Swift.
- [Kotlin](https://sonnetcode.com/technologies/kotlin): Language — production systems in Kotlin.
- [C++](https://sonnetcode.com/technologies/cpp): Language — production systems in C++.
- [React](https://sonnetcode.com/technologies/react): Framework — production systems in React.
- [Next.js](https://sonnetcode.com/technologies/next-js): Framework — production systems in Next.js.
- [Vue.js](https://sonnetcode.com/technologies/vue-js): Framework — production systems in Vue.js.
- [Angular](https://sonnetcode.com/technologies/angular): Framework — production systems in Angular.
- [Node.js](https://sonnetcode.com/technologies/node-js): Framework — production systems in Node.js.
- [Django](https://sonnetcode.com/technologies/django): Framework — production systems in Django.
- [.NET](https://sonnetcode.com/technologies/dotnet): Framework — production systems in .NET.
- [Spring Boot](https://sonnetcode.com/technologies/spring-boot): Framework — production systems in Spring Boot.
- [Ruby on Rails](https://sonnetcode.com/technologies/ruby-on-rails): Framework — production systems in Ruby on Rails.
- [Laravel](https://sonnetcode.com/technologies/laravel): Framework — production systems in Laravel.
- [FastAPI](https://sonnetcode.com/technologies/fastapi): Framework — production systems in FastAPI.
- [PyTorch](https://sonnetcode.com/technologies/pytorch): Framework — production systems in PyTorch.
- [AWS](https://sonnetcode.com/technologies/aws): Platform — production systems in AWS.
- [Google Cloud](https://sonnetcode.com/technologies/google-cloud): Platform — production systems in Google Cloud.
- [Azure](https://sonnetcode.com/technologies/azure): Platform — production systems in Azure.
- [Kubernetes](https://sonnetcode.com/technologies/kubernetes): Platform — production systems in Kubernetes.
- [Docker](https://sonnetcode.com/technologies/docker): Platform — production systems in Docker.
- [Terraform](https://sonnetcode.com/technologies/terraform): Platform — production systems in Terraform.
- [PostgreSQL](https://sonnetcode.com/technologies/postgresql): Platform — production systems in PostgreSQL.
- [MongoDB](https://sonnetcode.com/technologies/mongodb): Platform — production systems in MongoDB.
- [Redis](https://sonnetcode.com/technologies/redis): Platform — production systems in Redis.
- [Snowflake](https://sonnetcode.com/technologies/snowflake): Platform — production systems in Snowflake.
- [Databricks](https://sonnetcode.com/technologies/databricks): Platform — production systems in Databricks.

## Recent writing

- [DPO Becomes the 2026 Default Preference Optimization Substrate](https://sonnetcode.com/blog/dpo-becomes-default-preference-optimization-2026): DPO is now the default preference-optimization substrate — cheaper, simpler, and squeezing the RLHF workforce budget on every FY27 alignment plan.
- [The 37% Lab-to-Production Gap Enterprise AI Teams Buy Blind](https://sonnetcode.com/blog/enterprise-ai-agent-37-percent-lab-production-gap): Enterprise agentic AI shows a 37% gap between lab benchmarks and production, with 50x cost variance. Domain evals decide which agent survives contact.
- [Fable 5 Returns With a Cybersecurity Classifier: What Changes](https://sonnetcode.com/blog/fable-5-cybersecurity-classifier-integration-shift): Anthropic redeployed Fable 5 on July 1 with a new cybersecurity classifier — the interception layer changes what production AI teams must instrument.
- [SWE-Bench Audit: 19.8% of 'Solved' Tasks Are Reward-Hacked](https://sonnetcode.com/blog/swe-bench-audit-19-8-percent-reward-hacked-solves): An audit found 19.78% of SWE-bench top-30 'solved' cases pass by coincidence or reward-hacking — the FY27 model-selection basis needs team-owned evals.
- [Fable 5's 19-Day Shutdown Prices Single-Vendor AI Concentration Risk](https://sonnetcode.com/blog/fable-5-19-day-shutdown-vendor-concentration-risk): US export controls froze Fable 5 for 19 days. It's back July 1 — but the concentration lesson for FY27 AI plans is that portability is no longer optional.
- [Cursor Teams Splits Usage Pools, Adds Premium Seat July 1 2026](https://sonnetcode.com/blog/cursor-teams-composer-25-premium-seat-july-2026): Cursor's July 1 Teams pricing splits Composer/Auto from third-party API credits and adds a 5×-usage Premium seat — the FY27 AI-IDE spend policy needs a rewrite.
- [Rapidata's Online RLHF Compresses Human-Feedback Loops to Hours](https://sonnetcode.com/blog/rapidata-online-rlhf-feedback-hours-not-months): Rapidata's €7.2M-funded platform moves human judgment into the training loop — cycles drop from months to hours, human signal is the new frontier scarcity.
- [Google Ships Nano Banana 2 Lite: $0.034/Image, 4-Second Latency](https://sonnetcode.com/blog/google-nano-banana-2-lite-gemini-omni-flash-media): Google shipped Nano Banana 2 Lite and Gemini Omni Flash on June 30 — image gen at $0.034 per 1K image, video at $0.10 per second, all watermarked.

## Optional

- [AI Training Glossary (GitHub)](https://github.com/Sonnet-Code/ai-training-glossary): Public glossary of human-in-the-loop AI terms (SFT, RLHF, DPO, red-teaming, evaluation) maintained by SONNET CODE.
- [Awesome Human-in-the-Loop AI (GitHub)](https://github.com/Sonnet-Code/awesome-human-in-the-loop): Curated list of papers, tools, and datasets for human-in-the-loop AI training.
- [Privacy Policy](https://sonnetcode.com/privacy): How we handle data from the site and contact form.
- [Terms](https://sonnetcode.com/terms): Terms of use for the marketing site.
- [RSS feed](https://sonnetcode.com/blog/rss.xml): Full blog feed in RSS 2.0.
- [Sitemap](https://sonnetcode.com/sitemap.xml): Canonical index of every indexable URL with hreflang alternates.