RAG applicationdevelopment services for products that answer from your own documents, and show each user only what they may see.

A retrieval pipeline is not a product. We build the application around it: sign-in, per-user access to documents, an answer screen with sources people can open, admin tools for your content team, and web and mobile clients your users will keep using.
Discuss your RAG application

Retrieval gives you an answer. The application decides if anyone trusts it.

A RAG project can stall even when it already returns decent answers in a notebook. What is missing is the software around them: who is allowed to see which document, how a user checks where an answer came from, what happens when a file is replaced or deleted, how the tool behaves on a slow connection, and what each question costs you. That is ordinary product engineering applied to an unusual backend, and it is often the larger share of the work.

Where RAG applications break after the demo

01

Answers leak restricted documents

The index holds everything, and the search ignores who is asking. An intern's question gets answered from a board memo or another customer's contract.
02

No way to check an answer

The app prints a paragraph without sources. Users cannot open the page it came from, so they either trust it blindly or stop using it.
03

The index shows last month's content

A policy was updated or a file deleted, but the old version still feeds answers because nothing re-syncs the index when sources change.
04

A chat box where a workflow was needed

Support agents needed a draft reply inside the ticket. They got a separate chat tab, so they copy and paste between two windows.
05

A long wait on a blank screen

The answer arrives all at once after a long wait. Without streaming, progress states and a way to cancel, the tool feels broken even when it is right.
06

Nobody can see what users ask

There are no logs of questions, sources used, ratings or cost per request, so the team cannot tell which answers fail or why the bill grew.

Four kinds of RAG application we build

The retrieval core is similar in all four. The screens, permissions and integrations are what differ, and they define the scope.

Internal knowledge search

  • One search box over wiki, drives and tickets
  • Results limited to what the employee can open
  • Answers with links to the exact source page

Support copilot

  • Draft replies inside the agent's ticket view
  • Sources from manuals and resolved tickets
  • The agent edits and sends, not the model

Document Q&A in your SaaS

  • Each customer asks about their own files
  • Tenant data separated in the index
  • Usage tracked per account for billing

Field and mobile assistants

  • Manuals and procedures on iOS and Android
  • Short answers built for a small screen
  • Clear behavior on weak connections

Signs you need a RAG application, not another prototype

If two or three of these describe your situation, the retrieval idea is proven and the product work is what remains.

1

The pilot lives in a notebook or a shared demo link

It works for the people who built it and has no sign-in, no roles and no place in your product.

2

Security review stopped the rollout

Your security or legal team asked how document access is enforced, and the honest answer was that it is not.

3

Customers ask for Q&A inside your SaaS

They want to ask questions about their own data in your product, with each tenant's content kept apart.

4

People search several systems for one answer

The wiki, the drive, the ticket system and chat history each hold a part, and employees ask a colleague instead.

5

Support repeats the same lookups

Agents dig through manuals and past tickets for every reply, and new hires take a long time to learn where things are.

6

Your team knows the model side only

You have someone who can tune retrieval, but nobody to build the front end, mobile client, permissions and admin tools.

What we build

RAG software development, from the answer screen to the admin panel

Answer and search interface

Streaming answers, cited passages you can open in the original document, follow-up questions, filters and a plain search mode for when users want a list.

Sign-in and document permissions

Single sign-on, roles and per-document access rules applied at retrieval time, so restricted text does not reach the model for a user who cannot see it.

Multi-tenant document Q&A

For SaaS products: each customer's content is indexed and queried within its own boundary, with per-tenant settings and usage limits.

Source connectors and sync

Imports from your wiki, file storage, ticket system or database, with scheduled or event-based updates so edits and deletions reach the index.

Admin and content tools

Screens where your team adds or removes sources, sees indexing status, reviews flagged answers and edits the instructions the assistant follows.

Web and mobile clients

A React or Next.js web app and iOS and Android apps on the same API, or the feature embedded into the product you already have.

Feedback and review flows

Thumbs up and down, a reason field and a queue where an expert corrects weak answers. That feedback becomes the test set for later changes.

Usage, quality and cost dashboards

Questions asked, unanswered topics, ratings, response time and model spend per user or account, visible to you without asking an engineer.

What a finished RAG application includes

A list you can use to compare proposals. If a vendor's scope skips one of these, ask who builds it.

Access control

Sign-in through your identity provider

Permissions copied from the source systems

Access filter applied during retrieval, not after generation

Audit log of who asked what

Answer experience

Streaming text with a visible progress state

Citations that open the source at the right place

A clear "not found in your documents" reply

Conversation history per user

Content lifecycle

New and changed files indexed automatically

Deleted files removed from answers

Indexing status and errors shown to admins

Re-index without downtime when the setup changes

Operations

Logs of questions, sources and answers

Cost per request and per account

A test set of questions run before each release

Rate limits and spending caps

Technologies behind a RAG application

The application layer runs on a familiar web stack. The vector store, the orchestration library and the model provider are chosen with you for each project: for example pgvector inside PostgreSQL versus a dedicated vector database, a library such as LangChain or LlamaIndex versus plain code, a hosted model versus one you run yourself.

Python
FastAPI
PostgreSQL
TypeScript
React
Next.js
AWS
Docker
Who is this for

For teams that need RAG as a working product

SaaS and product companies

You want document Q&A or an assistant as a feature of your product, with tenant separation and usage you can bill for.

Mid-size companies

Your knowledge sits in several systems and employees lose time finding it. You need one internal tool with your access rules.

Founders

Your product idea is an assistant over a specific body of content, and you need a first version real users can sign in to.

Teams with a working pilot

Retrieval quality is acceptable and the pilot now needs an interface, permissions, monitoring and a release process.

What do you need built?

An internal search tool

One place to ask across wiki, drives and tickets.

A support copilot

Draft replies with sources in the agent's workspace.

Q&A inside our SaaS

Customers ask questions about their own data.

A mobile assistant

Manuals and procedures for people away from a desk.

A product around our pilot

UI, sign-in and permissions for an existing pipeline.

Permissions done properly

Access rules enforced in a tool that is already live.

How a RAG application gets built

01

Users, sources and access rules

We list who will ask, which systems hold the content, how permissions work there today, and write down sample questions with the answers you expect.

02

Clickable prototype on real documents

A thin version with a sample of your content, so you can judge answer quality and the screen design before the full build is scoped.

03

Application build

Interface, sign-in, permission filter, connectors and admin tools, delivered in sprints with a demo at the end of each one.

04

Pilot with a small group

A limited set of users works with it on real tasks. We read the logs and ratings with you and fix what they show.

05

Rollout and monitoring

Release to everyone, with dashboards for usage, quality and cost and a set of test questions that runs before each change.

06

Next sources and features

More content sources, new clients or workflow integrations, added in the order your usage data suggests.

How we work

Choose how to start

Discovery Sprint

most popular

2-week fixed-price start

Fixed price. The build is quoted after it.

For teams that have the content and the idea, and need a scoped plan and a price before committing to a build.

Users, sources and permission model mapped

Prototype on a sample of your documents

Screen designs for the main flows

Architecture and model options with trade-offs

Estimate and release plan for the first version

Start with discovery

Dedicated product team

Backend, front-end, mobile and QA on your application

Monthly, team-based.

For a RAG application that is in development or live and needs steady releases next to your own roadmap.

Python and web engineers, mobile when needed

QA for the app and for answer quality

A demo at the end of every sprint

Usage and cost reviewed with you regularly

Team size adjusted as the scope changes

Discuss your team

AI products we've built and rescued

Data MANAGEMENT & payroll

AI Payroll Platform (NDA)

Europe

An AI-powered payroll validation platform that extracts data from salary slips, verifies payroll calculations, and automates reporting and approval workflows for HR and finance teams

Before
→
after
↓
Manual payroll validation
↑
17% fewer salary calculation errors
↓
Complex PDF extraction
↑
AI-powered PDF data extraction
↓
Manual approval workflows
↑
Automated payroll validation and reporting workflows
↓
 Limited processing scalability
↑
Scalable platform for payroll processing
AI Commerce PlatformE

QLode

USA
Europe

An AI-powered fashion commerce platform that helps retailers deliver personalized shopping experiences through virtual styling, AI recommendations, image search, and intelligent product discovery.

Before
→
after
↓
AI search didn't scale
↑
AI-based recommendation engine developed
↓
Scalable infrastructure needed
↑
Image & text search implemented
↓
Complex retailer integrations
↑
Multi-retailer integration architecture built
↓
Product discovery wasn't production-ready
↑
High-performance backend for AI-driven flows
AI CONSUMER APPS

AI Mobile Editors

Global
4M+
DOWNLOADS COMBINED
Before
→
after
↓
Existing  codebase required stabilization
↑
Both apps stayed instore
↓
AI features broken or misleading
↑
AI rebuilt to production quality
↓
App Store compliance at risk
↑
App Store compliance restored
↓
Reviews declining fast
↑
Product stabilized 

What clients say about working with Gilzor

Verified reviews from Clutch. The products differ, the way we work is the same.

“They were incredibly fast and efficient at scoping the project and then delivered within very tight deadlines.”
Clement Nevoret CEO, Pointblank GmbH Mobile app development · $10,000 to $49,999 Verified review on Clutch
“I was impressed with how quickly we got a stable and well-designed product.”
Natalia Burakova Senior Product Manager, Impala Studios Mobile app development and support · $200,000 to $999,999 Verified review on Clutch
“The team met all commitments, aligning with our company's objectives.”
Verified client Individual entrepreneur, IT company Mobile app, API and UX/UI design · $50,000 to $199,999 Verified review on Clutch

The people you will talk to

Art Scherbakov
Art ScherbakovCo-Founder
Andrew Laminsky
Andrew LaminskyCTOLinkedIn
Yuri Rudenya
Yuri RudenyaHead of Mobile Development at GilzorLinkedIn
Alena Timofeeva
Alena TimofeevaProduct Marketing LeadLinkedIn

Make the most of the experienced team

We are a global team of
creative
and
strategic thinkers
who specialize in building custom digital products
from scratch. Our main goal is to
deliver high-quality solutions
that meet our clients' needs.
We are a global team of
creative
and
strategic thinkers
who specialize
in building custom digital products
from scratch. Our main goal is to
deliver high-quality solutions
that
meet our clients' needs.
Learn more
85%
recurring customers
12M
the biggest fundraising round by one startup
X3 MRR
growth of partner's business in 5 mos
2 weeks
for project start
5+ years
av. partnership duration with SMBs and product companies

Why Gilzor

We are a product development company that builds AI features, not a research lab. For a RAG application that matters, because most of the work is the product around the model.

What we bring

Web, mobile and backend in one team

The same team builds the API, the web app and the iOS and Android clients, so the AI feature is not handed between vendors.

AI work on real documents

On an AI payroll platform we built PDF data extraction from salary slips with automated validation, and salary calculation errors dropped by 17%.

Search experience

For QLode, an AI fashion commerce product, we built image and text search and a recommendation engine on a high-performance backend.

Products shipped

70+ products launched for startups, SMBs and product companies.

Clients who return

85% of our clients come back with new work. We are rated 5.0 on Clutch from 5 verified reviews.

What makes us different

Permissions before polish

We settle who can see what at the start, because it shapes the index and is costly to add later.

Every answer shows its source

Citations are part of the first prototype, not a later feature.

Your accounts, your code

The repository, cloud account, index and model provider keys belong to you from day one.

Plain advice on scope

If plain search or a simple FAQ would solve the problem, we tell you before you pay for a build.

Overlap with US hours

Our team in Poland shares part of the US working day for calls, demos and reviews.

What our clients
frequently ask

What do your RAG application development services include?

The whole application: the user interface, sign-in and permissions, connectors to your content sources, the retrieval and generation backend, admin tools, logging and dashboards, and web and mobile clients. You can also hire us for the application layer only, if your team already has a retrieval pipeline it is happy with.

How is a RAG application different from a RAG pipeline?

The pipeline turns a question and a set of documents into an answer. The application is everything a user and an administrator touch: screens, accounts, access rules, content management, history, feedback and monitoring. A pipeline can be tested by an engineer in a notebook. An application can be given to all your employees or customers.

How do you make sure users only get answers from documents they are allowed to see?

Each indexed passage carries the access rules of its source document, and the search is filtered by the signed-in user's identity before anything is sent to the model. We sync those rules from the source systems so a change in access there reaches the index. Filtering after the answer is generated is not enough, because the restricted text has already shaped the reply.

Can you add RAG to our existing web or mobile app instead of building a new one?

Yes. We add an API and embed the feature in your current front end, using your existing sign-in and roles. If the main task is connecting RAG to existing systems and data, our RAG implementation page describes that work in more detail.

Which models and vector databases do you use?

We choose them with you during discovery, based on your data location rules, expected volume and budget. Typical decisions are a hosted model versus a self-hosted one, and a vector extension in your existing PostgreSQL versus a separate vector database. We keep the model and the store behind an interface in the code so either can be replaced later.

How long does RAG application development take?

It depends mostly on the number of content sources, how complex the permissions are and how many clients you need, and less on the retrieval itself. A 2-week Discovery Sprint ends with a prototype on your documents, a scope and a timeline for the first release. Projects can start in about two weeks.

How is a RAG application priced?

The Discovery Sprint is a fixed price. After it, the first version is usually quoted as a fixed price for the agreed scope, and ongoing work is billed monthly for a dedicated team. Model and hosting costs are paid by you directly to the providers, and we estimate them per request during discovery.

What happens when the application cannot find an answer?

It is designed to say so. When retrieval returns nothing relevant, the app tells the user the answer was not found in the available documents and can suggest related sources or a person to ask. Those unanswered questions are logged, which gives your content team a list of what is missing.

No sales pitch

Tell us about your RAG application

Who will use it, where the content lives today and what access rules apply. We'll reply with a suggested scope, the open questions and a rough estimate.

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