Do you replace REST with GraphQL?

Rarely all at once. Most engagements wrap the existing REST services with a GraphQL layer first, then migrate the backends behind it in increments that each carry a rollback.

When is federation the wrong answer?

When one team owns the whole graph. Federation pays off when several teams need to ship parts of the schema independently. Below that, a single gateway with clear module boundaries is simpler and faster.

Can a GraphQL API satisfy a HIPAA or PCI audit trail?

Yes, when request tracing is designed in: every operation logged with the caller, the fields it touched and the data it resolved, stored where the auditor can read it. It does not appear by itself. It is part of the architecture.

Which stack do you work with?

Apollo Federation, Apollo Client and GraphQL Mesh at the gateway; gqlgen and entgo on Go; Hasura, Prisma and Strapi on Node; PostgreSQL and Redis underneath. The design comes first, the stack follows the team.

GraphQL Architecture and Federation

One API over many systems

Most companies do not need GraphQL because it is fashionable. They need it because they have several backends, several clients and one team that is tired of writing the same aggregation code three times. A well-designed graph gives every consumer exactly the data it asks for, keeps the contract in one place, and turns a dozen REST endpoints into a schema the whole company can read.

I design that graph: the schema and its naming rules, where the boundaries between teams fall, how queries stay fast under load, and how every request leaves a trail that an auditor can follow.

What I design

Schema-first contract. The schema is the API. Types, queries and mutations are written and reviewed before any resolver exists, so validation and documentation come for free.
Federation boundaries. Entity ownership, subgraph responsibilities and gateway configuration, so several teams can ship their part of the graph without a coordination meeting.
Query performance. N+1 elimination with DataLoader-style batching, caching where it is safe, and query cost limits where it is not.
Real-time delivery. Subscriptions for dashboards, notifications and collaborative screens, with a clear answer to "what happens when the connection drops".
Request tracing. Audit-ready logging across the graph: who asked, what was resolved, from which system.
Incremental adoption. A GraphQL layer over the REST APIs you already have, so the migration underneath can happen one service at a time.

A federated gateway over seven legacy systems

A healthcare platform had seven legacy systems and eight-second data retrieval on the screens that mattered. Replacing the systems was a multi-year, multi-million rewrite nobody wanted to fund. I designed a federated GraphQL gateway that wrapped all seven without changing them, gave the product teams one query language, and moved the slow aggregation into resolvers that batched and cached correctly.

8 s to 400 ms per query, seven systems behind one API

The same approach, applied to a mobile product, cut the app's API calls by 80 percent: one query per screen instead of a chain of REST calls.

What you receive

Schema design document. Your API surface with type definitions, query and mutation contracts and naming conventions.
C4 architecture diagrams. System context, container and component views showing where GraphQL sits in your stack.
Query optimization report. N+1 analysis, batching recommendations and a caching strategy with the performance gain you can expect from each.
Federation blueprint. Service boundaries, entity ownership and gateway configuration, when federation is warranted.
Implementation roadmap. Prioritized steps with effort estimates, so your team knows what to build and in which order.

How it runs

A free 30-minute call to understand the system and the constraint you are fighting. Then one to two weeks of review and design, a written scope up front, and a walkthrough of the deliverables with your team. If you want implementation support afterwards, I work with a small network of senior engineers I have shipped with for years and stay involved as the technical lead. The engagement can also stay purely advisory.