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REST → GraphQL

REST to GraphQL Migration

Introducing GraphQL alongside your REST API rather than instead of it, with query scope limits and resolver performance handled before clients arrive.

35+
GraphQL Schemas
0
Breaking Changes
Scope Review First
Typical Timeline
Bounded
Query Scope
GraphQL schema code on a monitor
Overview

GraphQL solves over-fetching and introduces new problems

The case for GraphQL is real. Mobile clients stop making six calls to render one screen, front-end teams stop waiting for custom endpoints, and the schema becomes documentation that cannot go stale. Those are genuine wins.

What comes with it is a different failure surface. A single query can request arbitrary depth, which is a denial-of-service vector unless bounded. Naive resolvers turn one query into hundreds of database round trips. And unlike REST, you cannot see from an access log what a request actually scope.

So we introduce GraphQL alongside REST, with depth limiting, scope analysis, dataloader batching and per-operation tracing from the first schema rather than after the first outage.

Teams that start here often pair it with API integration, web app development and mobile app development.

REST tells you what a request scope from the URL. GraphQL does not, which is why scope analysis and tracing have to exist before the first client ships.

API architecture diagram on a screen
The Problem

Where GraphQL adoptions go wrong

Four problems that appear once real clients start querying.

N+1 Resolvers

A list query resolves each item separately, turning one request into hundreds of database calls under load.

Unbounded Queries

No depth or complexity limit, so a deeply nested query becomes an availability incident from a single client.

Schema Mirrors Database

Types map one to one onto tables, so the API exposes storage decisions and becomes hard to evolve.

No Per-Operation Visibility

Everything is one POST endpoint, so monitoring cannot tell which query is slow or expensive.

What's Included

What a GraphQL migration covers

A schema clients can rely on, with the operational safety it needs.

Schema Design

Types modelled on domain concepts rather than tables, with nullability and pagination decided deliberately.

Incremental Adoption

GraphQL runs alongside REST, often resolving through existing services, so nothing has to be rewritten to start.

Dataloader Batching

Per-request batching and caching so list queries make one database round trip per relationship rather than one per item.

Scope Controls

Depth limiting, complexity scoring and persisted queries, so no single request can threaten availability.

Per-Operation Observability

Tracing and metrics by operation name, so slow and expensive queries are identifiable in production.

Client Migration

Front-end and mobile clients moved query by query, with REST retired only once traffic shows nothing calls it.

Our Process

From schema design to client migration

GraphQL added alongside REST, never instead of it.

01
Audit

Existing endpoints, client call patterns and the screens that currently need multiple round trips are catalogued.

02
Schema Design

Domain-modelled types, pagination and error semantics agreed with client teams before implementation.

03
Gateway

GraphQL layer deployed alongside REST with batching, depth limits and tracing from the first resolver.

04
Client Migration

Screens moved one at a time, measuring round trips and payload size against the REST baseline.

05
REST Retirement

Endpoints retired only when traffic confirms no client depends on them.

Tech Stack

The stack behind our GraphQL layers

Schema-first, with performance guarded from day one.

01
Server

Schema-first implementations with typed resolvers generated from the schema.

Apollo ServerGraphQL YogaPothosCode Generation
02
Performance

Batching and caching per request, because the N+1 problem is the default without them.

DataLoaderQuery PlanningResponse CachingPersisted Queries
03
Safety

Bounded scope per request, so one client cannot take the API down.

Depth LimitingComplexity AnalysisRate LimitingAllowlists
04
Observability

Metrics and traces by operation name rather than by endpoint.

Apollo StudioOpenTelemetrySlow Query LogsGrafana
In The Field

What this looks like in production

Marketplace · Mobile API Consolidation

Six requests per screen down to one

A marketplace mobile app made six REST calls to render its main listing screen. On poor connections the screen took several seconds to populate and partial failures produced half-rendered states that were difficult to reason about.

We introduced GraphQL alongside the existing API, resolving through the same services. The listing screen became a single query. The first load test then immediately exposed an N+1: one query was producing four hundred database calls.

Dataloader batching brought that to nine. Depth limiting and complexity scoring went in before any client shipped, which meant the migration never produced an availability incident.

6 → 1
Requests per screen
400 → 9
Database calls per query
0
Breaking changes to REST
Why Tech Team 4U

GraphQL introduced without a rewrite

The schema goes in alongside REST and resolves through your existing services, so adoption is incremental and REST retires only when nothing calls it.

Strangler Fig, Not Big Bang

We move one slice at a time behind a router, with both systems live, so every step is small and every step is reversible.

Weekly Transparency

A working demo and a written note every Friday covering what shipped, what slipped and what it means for the date. No status theatre.

Staged, Not Risky

Nothing goes live in one jump. We run in parallel or behind a flag until the numbers say it is safe to switch over.

35+
GraphQL Schemas
10+
Years Engineering
0
Breaking Changes
Bounded
Query Scope