// US-based LLM developers

Free project plan & cost estimate in 48 hours.

Senior LLM developers, based in the US, working your hours

LLM features, RAG search, and AI agents, built by US engineers who ship AI to production with evals and guardrails.

  • Interview engineers before you pay anything
  • 100% U.S.-based, working your hours
  • No brief or spec needed to get started

First 5 Dev Hours Free

Project plan. Roadmap. Cost & ROI estimation.

Real engineers. Real conversations.

Talk to an engineer. Not a salesperson.

Free · No commitment · Project-focused call

Most teams interview matched engineers within a week

Not the right fit? We bring in a replacement

Get your free project plan

Three quick steps. No brief needed.

Step 1 of 3

NextGen will never sell any data you give to us, we'll only reach out.

Free · No commitment · Reply within one business day

// teams we've worked with

FileFormsBread FinancialFinCEN AdvisorsFinovoraTaxNowSagemont Tax Services
“NextGen scaled us from 2 to 7 dedicated engineers in under a quarter. Enterprise-grade capacity, zero agency drag.”
Director of Engineering · FileForms

Sound familiar?

  • Hiring a senior LLM developer full-time is taking months.
  • Your LLM codebase has grown messy and every change breaks something else.
  • Offshore hand-offs and time-zone gaps turn one-day fixes into week-long threads.
  • You need someone senior enough to make decisions, not just close tickets.
Get matched engineers this week One call. Matched profiles. You pick who to interview.

What our LLM engineers build

RAG & agents

Search, assistants, and automation grounded in your data.

Rescue & upgrades

Existing LLM work stabilized, documented, and brought up to date.

Integrations

LLM connected cleanly to the rest of your systems.

How it works

  1. 01

    Pick a time

    Book a 30-minute project call directly in our calendar.

  2. 02

    Talk through the problem

    Tell us what needs building, what's stuck and what success looks like. No spec needed.

  3. 03

    Your plan in 48 hours

    Get your project plan, roadmap, cost and ROI estimates. The plan is yours to keep.

  4. 04

    First 5 dev hours free

    Agree the scope with our team. Decide whether to continue before any paid work begins.

Common questions

Will this turn into a sales pitch?

No. The call is about your project: what needs building, what's stuck, and whether we have the right engineers. If we're not a fit, we'll say so.

What do I get for free?

A project plan, roadmap, cost estimate and ROI estimate within 48 hours of your project call. Your first 5 development hours are free, too. We agree the scope and any paid work with you before proceeding.

Do I need a spec or brief?

No. Tell us the problem in plain words and we'll help shape the scope with you.

Are the engineers really in the U.S.?

Yes. Every engineer lives and works in the United States. No offshore hand-offs, and that's in the contract.

What our clients say

FileForms client review
"NextGen scaled us from 2 to 7 dedicated engineers in under a quarter. Enterprise-grade capacity, zero agency drag."
Director of Engineering · FileForms
Sagemont Tax Services client review
"Their R&D tax credit workflow platform paid for itself in the first filing season."
VP, Product · Sagemont Tax Services
TaxNow client review
"AI-native from day one. Our IRS transcript pipeline runs 24/7 without a human in the loop."
Founder · TaxNow
Bremar & Armstrong client review
"Property tax appeals used to take weeks. Their comp analysis tooling turned it into hours."
Managing Partner · Bremar & Armstrong
Star Health client review
"The AI intake agent handles our tier-1 patient calls with a hand-off cleaner than our old call center."
Head of Operations · Star Health
SEM Restaurant Group client review
"POS, inventory, ordering — all unified. We finally have one source of truth across every location."
COO · SEM Restaurant Group
Trademark Waste Solutions client review
"The procurement platform paid for itself in the first quarter of use."
Director of Operations · Trademark Waste Solutions
PlayerTrader client review
"They shipped our matching engine in 6 weeks. Our old team would've taken 6 months."
CTO · PlayerTrader
Guidant Global client review
"Enterprise-grade delivery without the enterprise-agency price tag."
Program Director · Guidant Global
PM Insights client review
"Their team plugged into our sprint on day one. Zero ramp time."
Head of Engineering · PM Insights
FileForms client review
"NextGen scaled us from 2 to 7 dedicated engineers in under a quarter. Enterprise-grade capacity, zero agency drag."
Director of Engineering · FileForms
Sagemont Tax Services client review
"Their R&D tax credit workflow platform paid for itself in the first filing season."
VP, Product · Sagemont Tax Services
TaxNow client review
"AI-native from day one. Our IRS transcript pipeline runs 24/7 without a human in the loop."
Founder · TaxNow
Bremar & Armstrong client review
"Property tax appeals used to take weeks. Their comp analysis tooling turned it into hours."
Managing Partner · Bremar & Armstrong
Star Health client review
"The AI intake agent handles our tier-1 patient calls with a hand-off cleaner than our old call center."
Head of Operations · Star Health
SEM Restaurant Group client review
"POS, inventory, ordering — all unified. We finally have one source of truth across every location."
COO · SEM Restaurant Group
Trademark Waste Solutions client review
"The procurement platform paid for itself in the first quarter of use."
Director of Operations · Trademark Waste Solutions
PlayerTrader client review
"They shipped our matching engine in 6 weeks. Our old team would've taken 6 months."
CTO · PlayerTrader
Guidant Global client review
"Enterprise-grade delivery without the enterprise-agency price tag."
Program Director · Guidant Global
PM Insights client review
"Their team plugged into our sprint on day one. Zero ramp time."
Head of Engineering · PM Insights
// trusted by
FileForms
Bread Financial
FinCEN Advisors
Finovora
TaxNow
Sagemont Tax Services
Guidant Global
Bremar & Armstrong Property Tax Consultants
Inventive Advisors
PM Insights
S. Rice Group
Star Health
SEM Restaurant Group
Trademark Waste Solutions
Lee Cohen
PlayerTrader
Perrrign AI
Blackhat
BeatBallot
Boosted Earnings
Torchlight 250
Canary
Billing Geeks
ReLi Med Solutions
Green Leaf Wellness
// partners & platforms
AWS Partner
Google Cloud Partner
Microsoft
Vanta Partner
Sanity Partner
Nanonets
// certifications & recognition
DesignRush — Top Software Development Company 2025
SAM Certified — Strategic Contracting Solutions
MBE Certified — Minority Business Enterprise
Powered by U.S. Small Business Administration
U.S. Commercial Service — U.S. Department of Commerce, International Trade Administration
// conferences & events
The AI Summit New York
New York Restaurant Show
NYSCC Suppliers' Day
Texworld New York City
Curve New York

You can hire senior US-based LLM developers from NextGen Coding Company to build retrieval-augmented generation systems, document assistants, and tool-calling applications. A project might use Python, FastAPI, OpenAI or Anthropic APIs, LangGraph, and PostgreSQL with pgvector. The engineering challenge is not just prompting: it is retrieving the right context, validating outputs, controlling tool access, and measuring failures before release.

Define representative questions, acceptable answers, response-time limits, and data-access boundaries before selecting a model or orchestration framework. Your engineer works from the US, follows your hours, and joins standups to keep application and evaluation work connected. NDA and full IP assignment are signed before code access. Book a 15-minute call to discuss your prototype, deployment requirements, and evaluation gaps.

// faq

Frequently asked questions

Should we use RAG or fine-tuning for an internal LLM assistant?
RAG usually fits questions grounded in changing internal documents, especially when users need citations and permission-aware retrieval. Fine-tuning can help with consistent behavior, formatting, or specialized patterns, but is not a reliable substitute for current source material. Start with an evaluation set, then determine whether failures come from retrieval, instructions, or model capability.
How do LLM developers reduce hallucinations in production?
No implementation can guarantee hallucination-free answers. Developers can improve grounding with better retrieval, source citations, structured outputs, and explicit abstention rules. Evaluation should separate retrieval failures from unsupported generation and include unanswerable questions. Schema validation checks output structure, not truth, so factual claims still need comparison against trusted source material.
Do we need LangChain or LangGraph to build an LLM application?
Not necessarily. A straightforward assistant may only need a model SDK, retrieval code, and ordinary application services. LangGraph can help when workflows require explicit state, branching, checkpoints, or human approval. Choose a framework when its abstractions solve a concrete orchestration problem, and avoid adding dependencies that make debugging model calls harder.
How can we protect private data in a RAG application?
Enforce authorization during retrieval, not just in the chat interface. Keep document permissions attached to indexed content and test for cross-user information exposure. Review model-provider retention settings, logging, secret handling, and tool permissions. Treat retrieved documents as untrusted input, and require application-side checks before any model-requested action reaches a sensitive system.
What should an LLM developer evaluate before we launch?
Build a representative test set covering correct answers, missing evidence, conflicting documents, prompt injection, and tool failures. Track retrieval relevance, groundedness, task completion, and latency separately. Tools such as LangSmith or Phoenix can support tracing and evaluation, but domain reviewers still need clear rubrics. Repeat evaluations when prompts, models, or indexed content change.
Are your developers really based in the US?
Yes. Every engineer lives and works in the United States. No offshore subcontracting and no hand-offs to another team. That's written into the contract.
How fast can someone start?
Most teams interview matched engineers within a week of the first call. Start dates depend on your interview process.

Related reading

Related hiring pages: · all stacks
// let's build something

Start your project request

Tell us what you're building — engineering capacity, AI, QA, cloud, or a fixed-scope software engagement. Our NYC team responds within one business day.

New York City, USAContact form
// what to expect
  • Response within 1 business day
  • 30-minute discovery conversation
  • Recommended engagement model & pricing
  • NYC-focused — in-person available
Start Project Request

Inbound sales only. All form information is encrypted in transit.