High-performance Rust gateway bridging gRPC to GraphQL with Apollo Federation v2.

Transform gRPC microservices into a unified GraphQL API. Zero GraphQL code required.

🚀 Performance at a Glance

Performance Rankings (Rust):
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
1. grpc_graphql_gateway    ████████████████████ 112,000 req/s 🚀
2. async-graphql (Actix)   █████████░░░░░░░░░░░  45,000 req/s
3. Juniper (Actix)         ████████░░░░░░░░░░░░  39,000 req/s

Data Efficiency Mode (GBP Ultra + Parallel):
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
JSON Payload (1GB)             ████████████████████ 100%
GBP Ultra (9MB)                ▏                    0.9% ⚡ (1,749 MB/s)

Compression by Data Pattern:
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Highly Repetitive (orgs/perms) ▏                    1%  (99% reduction)
Moderately Repetitive (enums)  █████                25% (75% reduction)
Unique/Varied (logs)           ██████████           50% (50% reduction)

✨ Features

Category	Capabilities
Core	Schema generation, Queries/Mutations/Subscriptions, WebSocket, File uploads
Live Queries	@live directive, Real-time updates, Invalidation triggers, WebSocket push
Federation	Apollo Federation v2, Entity resolution, DataLoader batching, No N+1
Production	Health checks, Prometheus, OpenTelemetry, Rate limiting, Circuit breaker
Security	Query depth/complexity limits, Introspection control, Query whitelisting
Performance	SIMD JSON, Sharded Cache, Response caching (Redis), APQ, Request collapsing
Connectors	REST APIs, OpenAPI integration, Multi-descriptor stitching

📦 Quick Start

[dependencies]
grpc_graphql_gateway = "0.5.5"
tokio = { version = "1", features = ["full"] }

use grpc_graphql_gateway::{Gateway, GrpcClient};

const DESCRIPTORS: &[u8] = include_bytes!(concat!(env!("OUT_DIR"), "/descriptor.bin"));

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    Gateway::builder()
        .with_descriptor_set_bytes(DESCRIPTORS)
        .add_grpc_client("service", GrpcClient::builder("http://localhost:50051").connect_lazy()?)
        .build()?
        .serve("0.0.0.0:8888")
        .await
}

Endpoints: http://localhost:8888/graphql | ws://localhost:8888/graphql/ws | ws://localhost:8888/graphql/live

🌐 Federation

Gateway::builder()
    .enable_federation()
    .with_entity_resolver(Arc::new(resolver))
    .build()?;

🎯 Apollo Router + Live Queries

The GBP Router provides a high-performance federation router with built-in live query support:

# router.yaml
server:
  listen: "0.0.0.0:4000"
  workers: 16

subgraphs:
  - name: users
    url: "http://localhost:4002/graphql"
  - name: products
    url: "http://localhost:4003/graphql"

rate_limit:
  global_rps: 100000
  per_ip_rps: 1000

# Circuit Breaker Configuration
circuit_breaker:
  failure_threshold: 10      # Open after 10 failures
  recovery_timeout: 30000    # Wait 30s (in ms) before retry
  half_open_max_requests: 5  # Allow 5 test requests

cargo run --bin router router.yaml

Features:

• ✅ Live Queries via WebSocket - ws://localhost:4000/graphql/live
• ✅ 99% Bandwidth Reduction - GBP compression for subgraph communication
• ✅ 150K+ RPS - Sharded cache + SIMD JSON parsing
• ✅ DDoS Protection - Two-tier rate limiting (global + per-IP)
• ✅ Real-time Updates - @live directive support
• ✅ APQ Support - Automatic Persisted Queries
• ✅ Request Collapsing - Deduplicate identical in-flight requests

Live Query Example:

const ws = new WebSocket('ws://localhost:4000/graphql/live', 'graphql-transport-ws');

ws.send(JSON.stringify({
  type: 'subscribe',
  id: '1',
  payload: {
    query: 'query @live { users { id name } }'
  }
}));

✅ Configuration Validation

You can validate your router.yaml without starting the server, useful for CI/CD pipelines:

cargo run --bin router -- --check router.yaml
# Output:
# 🔍 Validating configuration: router.yaml
# ✅ Configuration is valid!
#    - Subgraphs: 3
#    - Listen:    0.0.0.0:4000

🔧 Production Config

Gateway::builder()
    .enable_health_checks()           // /health, /ready
    .enable_metrics()                 // /metrics (Prometheus)
    .enable_tracing()                 // OpenTelemetry
    .with_query_depth_limit(10)       // DoS protection
    .with_query_complexity_limit(100)
    .with_response_cache(CacheConfig::default())
    .with_circuit_breaker(CircuitBreakerConfig::default())
    .build()?;

⚡ Live Queries

Real-time updates with the @live directive + 4 advanced optimization features:

# Connect to ws://localhost:8888/graphql/live

# Basic live query
query @live {
  users {
    id name status
  }
}

# Advanced: Filtered live query (50-90% bandwidth reduction)
query @live {
  users(status: ONLINE) {
    users { id name }
  }
}

Advanced Features

1. Filtered Queries - Server-side filtering: users(status: ONLINE) @live
2. Field-Level Invalidation - Track exactly which fields changed
3. Batch Invalidation - Merge rapid updates (70-95% fewer requests)
4. Client Caching Hints - Smart cache directives based on data volatility

Result: Up to 99% bandwidth reduction in optimal scenarios!

Configure in your proto:

rpc GetUser(GetUserRequest) returns (User) {
  option (graphql.schema) = { type: QUERY, name: "user" };
  option (graphql.live_query) = {
    enabled: true
    strategy: INVALIDATION
    triggers: ["User.update", "User.delete"]
    throttle_ms: 100  // Enables batching
  };
}

Trigger updates from mutations:

// After mutation, invalidate affected queries
LIVE_QUERY_STORE.invalidate(InvalidationEvent::new("User", "update"));

📚 Examples

cargo run --example greeter      # Basic queries/mutations/subscriptions
cargo run --example federation   # 3 federated subgraphs
cargo run --example live_query   # Live queries with @live directive

📦 Client SDKs

Official high-performance decoders for GBP:

• TypeScript/JavaScript: @protocol-lattice/graphql-binary-protocol

npm i @protocol-lattice/graphql-binary-protocol

import { GbpDecoder } from '@protocol-lattice/graphql-binary-protocol';
const decoder = new GbpDecoder();
const decompressed = decoder.decodeLz4(new Uint8Array(data));

🔗 Links

📖 Full Documentation • 📦 Crates.io • 💻 GitHub

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