What we do

Custom APIs & Integration

We build the connective tissue of your business: robust, well-documented APIs and integrations that let your systems, partners, and tools talk to each other reliably. From payment gateways to CRMs, we make disparate services behave as one. Whether you need a public API for your own product, a private integration between internal tools, or a one-time data migration, we make it documented, versioned, and reliable enough to build a business on.

Six systems connected by routed lines into a central hub, illustrating custom API development and system integration services.

Custom API development and system integration services

We build the connective tissue: documented REST and GraphQL APIs, and the integrations that make separate systems behave as one. Payment gateways, CRMs, ERPs, and the legacy system integration nobody else wants to open. If it has an API we connect it; if it does not, we build the bridge.

Who we build for

Businesses running disconnected tools

Orders live in one system, invoices in another, and a person retypes between them every day. That person is the integration, and they should not have to be.

Products that need a public API

Your customers or partners want to build against you. That needs versioning, auth, rate limits and documentation, not an endpoint bolted on.

Teams stuck behind a legacy platform

The old system cannot be replaced yet but it can be wrapped. An integration layer buys you time and a migration path.

What every engagement includes

  • A fixed price for the whole build, agreed after scoping and before any code
  • Weekly demos, so progress is something you see rather than something you are told
  • Senior engineers who own the outcome from first call to production
  • Applications built to WCAG 2.1 AA accessibility standards
  • Bilingual or multilingual delivery on request
  • Full source code, assets and IP transferred to you on final payment
NEXT.JSREACTREACT NATIVETYPESCRIPTTAILWINDNODE.JSPYTHONGODJANGOFASTAPIGRAPHQLREST APISPOSTGRESQLSUPABASEPRISMAREDISKAFKALLMS & RAGPINECONECLAUDEAWSGCPAZUREDOCKERKUBERNETESTERRAFORMCI/CDSTRIPE

The stack we use for this

Node.jsPythonGraphQLRESTPostgreSQLRedisKafkaWebhooks
05Pricing

One flat rate. No surprises.

Every engagement is scoped up front at a fixed price. No hourly billing, no scope-creep invoices. You know the number before we start.

From first call to production

A clear, four-step path with a fixed price agreed before we start. No surprises, no open-ended invoices.

  1. 01

    Discover

    Scope, goals, constraints. A fixed plan and price.

  2. 02

    Design

    Architecture and UX before production code.

  3. 03

    Build

    Senior engineers, weekly demos, no surprises.

  4. 04

    Ship and Scale

    Launch, monitor, and grow with you.

What clients say about working with us

5.0 average across 14 client reviews

Select an engagement

Full-stack web application

Canada

Engagement
$10,000
Duration
2 months
Maurizio and his team were great to deal with! Answered all questions and explained everything in detail and always had recommendations to help keep the progress of the build on track.
Client, Canada

Full-stack web application

Business client, Sweden

Engagement
$10,000
Duration
7 weeks
Client
Returning
Awesome job, we are very pleased with the result…
Returning business client, Sweden

Booking and invoicing platform

Business client, Canada

Engagement
$5,000-$10,000
Duration
7 months

A booking and invoicing application, built over a seven-month engagement.

We hired L3 to build our booking and invoicing application, and the experience exceeded expectations from start to finish. Their customer service and attention to detail were outstanding, and they were quick to resolve any issues that came up along the way. Everything works flawlessly now. Highly recommend them to anyone looking for a reliable development partner.
Business client, Canada

Full-stack web application

United Kingdom

Engagement
$5,000-$10,000
Duration
2 months
It was better than I could have imagined. I would highly recommend them. It was one of the best working experiences I have had.
Client, United Kingdom

Full-stack web application

United States

Engagement
$5,000-$10,000
Duration
3 weeks
The experience working with Level 3 was top notch. Excellent communication during the entire project. I highly recommend this team.
Client, United States

Full-stack web application

United Kingdom

Engagement
$2,500-$5,000
Duration
4 weeks
We spoke with a number of providers before selecting LevelThree Co, and from the outset Maurizio and his team stood out for how quickly they understood our requirements. They grasped the scope and intent of the project almost immediately and proposed a solution that was well thought through, technically sound, and fairly priced.
Client, United Kingdom

Full-stack web application

United States

Engagement
$2,500-$5,000
Duration
4 weeks
The attention to detail and the care they put into their work is rare when you work with someone you don't have a previous relationship with, and the LevelThree team are exceptional. Maurizio gave his personal time, attention and care to my project, including once calling me at 4am his time because he was working so hard on the project.
Client, United States

Full-stack web application

Australia

Engagement
$2,500-$5,000
Duration
2 weeks
Client
Returning
Can't speak highly enough of Maurizio, his team, and the work that was delivered. This is my second and largest order with them and somehow they managed to go above and beyond the already impeccable standard they've previously set.
Returning client, Australia

Full-stack web application

Saudi Arabia

Engagement
$2,500-$5,000
Duration
8 weeks
This is an exceptional service and a wonderful journey. All my expectations were met and above…
Client, Saudi Arabia

Full-stack web application

United States

Engagement
$2,500-$5,000
Duration
4 months
Client
Returning
This was by far the experience it needed to be. I would work with Level 3 for every project I have now and in the future. We walked through time together to create something amazing!
Returning client, United States

Full-stack web application

Serbia

Engagement
$1,000-$2,500
Duration
4 days
Went above and beyond to complete the work! Understood the assignment instantly, overdelivered on a very short deadline and even added some awesome features that were outside of the scope of work.
Client, Serbia

Full-stack web application

United States

Engagement
$1,000-$2,500
Duration
3 weeks
Absolutely outstanding experience. The work was delivered quickly and with impressive attention to detail. Communication was clear throughout the entire project, and every request was handled with professionalism and skill. The final result exceeded my expectations and made the whole process effortless on my end.
Client, United States

Website design and build

Real estate, United States

Engagement
$1,000-$2,500
Duration
2 weeks
The team at Level Three has exceeded my expectations! They took the time to understand my specific needs and preferences, and designed an incredibly gorgeous website for my real estate firm. They went the extra mile to ensure I had a seamless and positive experience.
Business client, United States

Pricing calculator web application

Home services, United States

Engagement
$400-$600
Duration
3 weeks

A pricing web application built from the client's own Excel cost model, porting complex logarithmic formulas into JavaScript so quotes could be generated for different home types and square footages.

Maurizio went above and beyond, adding extra features that made the app work and look even better than I expected. Because of the complex math behind my original calculator, we had to make a few revisions to get everything translating correctly from Excel to JavaScript. Maurizio and his team worked with me patiently to fine-tune the calculations until it was perfect.
Business client, United States

Common questions

Can you integrate with our existing systems, CRM, or payment provider?

Yes. Integration is core to what we do: payment gateways like Stripe, CRMs like Salesforce and HubSpot, and custom REST and GraphQL APIs that make your tools behave as one system. If it has an API, we connect it; if it does not, we build the bridge.

Who owns the code and intellectual property?

You do. On final payment, all source code, assets, and IP transfer to you with a clean handover and documentation. No lock-in.

How much does custom software development cost?

We work on a flat rate, not by the hour. After a short scoping call we give you one fixed price for the entire build, with clear deliverables and milestones, so you know the full cost before we write a line of code. No hourly meters, no surprise overages. The figure depends on scope, and scoping is free.

Start with a free discovery call. Transparent, flat-rate, delivered.

Ready to build something great?