Do you build REST or GraphQL APIs?

Both. REST is our usual default because it is simple to document, cache and hand to partner developers. We use GraphQL when a product has many different clients that need to fetch varied shapes of data. We will recommend one after hearing how the API will be used.

Can you integrate Stripe or another payment provider?

Yes. We build checkout, subscriptions, refunds and webhook handling with Stripe and with other providers that have a documented API. Which provider is allowed or practical depends on your country and business type, so please confirm account eligibility with the provider early.

What happens if a webhook is delivered twice or arrives late?

The handler is written to cope with both. Each event is verified, recorded and processed once using its unique identifier, so duplicates are ignored. Late or out-of-order events are checked against current state before they change anything. Failures are retried and logged so nothing disappears silently.

Can you document an API that already exists?

Yes. We can read an existing backend, write an OpenAPI description, add missing tests around the main endpoints and produce reference documentation. This is often the first step before a larger modernization project, and the documentation helps any developer who joins later, whether from our team or yours.

Who owns the API code and the provider accounts?

You do. Repositories, keys and provider accounts such as payment, email or cloud services belong to your company. We work inside them with the access you grant, and you can revoke that access at any time. If we ever stop working together, nothing needs to be transferred because it never left your control.

Call now +1 (929) 450-3261

+1 (929) 450-3261 Chat on WhatsApp

Empty studio desk by a window with a laptop, notebook, pencil and coffee mug

API and integrations

API development and integration for your product

We design and build custom APIs, connect payment providers and third-party systems, and handle webhooks so your software talks to the tools your business uses.

Book a scoping session Chat on Telegram

Documented REST and webhook APIs
Payments, CRMs and third-party systems
You own the code and accounts

What does API development and integration cover?

There are two related jobs. API development means building the interface your own product exposes, for your web app, mobile app, partners or customers. Integration means connecting your software to someone else's API, such as a payment provider, an accounting tool, a CRM or a shipping service.

We build both. Typical work includes a REST or GraphQL backend, authentication and API keys, rate limiting, background jobs, webhook receivers and senders, and the glue code that keeps two systems consistent when one of them is slow or down.

How do we build a custom API?

We start with the contract, not the code. Before building, we write the endpoints, request and response shapes, error formats and authentication rules, and review them with you. Once that is agreed, the work follows a predictable path:

Design: an OpenAPI description or equivalent that your frontend and partner developers can read.
Build: a typed backend, usually in TypeScript with Node.js or NestJS, Go or Python, on PostgreSQL.
Test: automated tests for the main paths and the error cases.
Document: reference docs and examples so the next developer is not guessing.
Version: a versioning plan so you can change the API without breaking existing clients.

How do payments and webhooks work in practice?

Payment integrations such as Stripe are mostly about handling the awkward cases: a customer who closes the tab mid-payment, a card that fails on renewal, a refund, a dispute, or the same event arriving twice.

We build webhook handlers that verify the signature, store each event, process it once even if it is delivered repeatedly, and retry safely on failure. We keep card data on the provider's hosted pages where possible, which keeps your own systems out of the most sensitive scope.

For crypto payment gateways and stablecoin payouts, we integrate the provider you choose. Whether you may accept or send crypto depends on your country and business, and that is your responsibility to confirm with a lawyer. Related reading: our fintech work and SaaS builds.

A single integration is often part of a larger MVP sprint or product build. Standalone API work is scoped after we see which systems are involved and how good their documentation is. See pricing for the typical ranges. A written quote follows a scoping conversation, and payment is by milestone.

The code, API keys and provider accounts are yours. We work in your repositories and your provider accounts so you are never locked in.

What are the limits we should be honest about?

You depend on other companies' APIs. They can change, add limits, charge more or go down, and we cannot control that. We build retries, logging and alerts to reduce the impact, but an outage at a provider can still affect your product.

Poorly documented or unstable third-party APIs take longer than the estimate for a clean one, and we flag that during scoping. We do not give legal or compliance advice on payments or data handling.

Fixed-scope sprints
Dedicated pods
Four practice areas
Client owns the code

How it works

1

Message us on WhatsApp or Telegram

Describe the product, the users and your timeline.

2

We scope and quote

You get a plan, an architecture outline and a written price range.

3

We build in sprints

You see working software each sprint and launch with a tested release.

Questions about custom software builders in United States

Do you build REST or GraphQL APIs?: Both. REST is our usual default because it is simple to document, cache and hand to partner developers. We use GraphQL when a product has many different clients that need to fetch varied shapes of data. We will recommend one after hearing how the API will be used.
Can you integrate Stripe or another payment provider?: Yes. We build checkout, subscriptions, refunds and webhook handling with Stripe and with other providers that have a documented API. Which provider is allowed or practical depends on your country and business type, so please confirm account eligibility with the provider early.
What happens if a webhook is delivered twice or arrives late?: The handler is written to cope with both. Each event is verified, recorded and processed once using its unique identifier, so duplicates are ignored. Late or out-of-order events are checked against current state before they change anything. Failures are retried and logged so nothing disappears silently.
Can you document an API that already exists?: Yes. We can read an existing backend, write an OpenAPI description, add missing tests around the main endpoints and produce reference documentation. This is often the first step before a larger modernization project, and the documentation helps any developer who joins later, whether from our team or yours.
Who owns the API code and the provider accounts?: You do. Repositories, keys and provider accounts such as payment, email or cloud services belong to your company. We work inside them with the access you grant, and you can revoke that access at any time. If we ever stop working together, nothing needs to be transferred because it never left your control.

Ready to scope your software project?

Message us on WhatsApp or Telegram with the product, the users and your timeline.

Chat on WhatsApp Chat on Telegram