OFREP Protocol

Flipswitch natively implements the OpenFeature Remote Evaluation Protocol (OFREP), so any language with an OpenFeature SDK and OFREP provider works directly — no custom integration needed.

Browse the full OpenFeature ecosystem for available SDKs and providers.

OFREP providers use polling for flag updates. For real-time SSE streaming, use an official Flipswitch SDK where available.

Supported Languages

.NET

ASP.NET, server-side

Rust

Tokio, Axum, server-side

Swift

iOS, macOS

PHP

Laravel, server-side

Ruby

Rails, server-side

Any language with an OpenFeature SDK and OFREP provider can connect to Flipswitch. If your language isn't listed above, check the OpenFeature ecosystem or use the direct HTTP API below.

Direct OFREP API

You can also call the OFREP endpoints directly via HTTP — useful for scripting, testing, or languages without an OFREP provider yet.

Single Flag Evaluation

curl -X POST https://api.flipswitch.io/ofrep/v1/evaluate/flags/dark-mode \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "context": {
      "targetingKey": "user-123",
      "email": "user@example.com"
    }
  }'

Response:

{
  "key": "dark-mode",
  "value": true,
  "variant": "enabled",
  "reason": "TARGETING_MATCH"
}

Bulk Evaluation

curl -X POST https://api.flipswitch.io/ofrep/v1/evaluate/flags \
  -H "X-API-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"context": {"targetingKey": "user-123"}}'

Response:

{
  "flags": [
    {"key": "dark-mode", "value": true, "variant": "enabled", "reason": "TARGETING_MATCH"},
    {"key": "max-items", "value": 50, "variant": "high", "reason": "DEFAULT"}
  ]
}

ETag Support

Use ETags for efficient caching:

# First request returns ETag header
curl -X POST https://api.flipswitch.io/ofrep/v1/evaluate/flags \
  -H "X-API-Key: YOUR_API_KEY" \
  -d '{"context": {"targetingKey": "user-123"}}'
# Response includes: ETag: "abc123"

# Subsequent requests with If-None-Match
curl -X POST https://api.flipswitch.io/ofrep/v1/evaluate/flags \
  -H "X-API-Key: YOUR_API_KEY" \
  -H 'If-None-Match: "abc123"' \
  -d '{"context": {"targetingKey": "user-123"}}'
# Returns 304 Not Modified if unchanged

All Supported Languages

Language	OpenFeature SDK	OFREP Provider
.NET	dotnet-sdk	dotnet-sdk-contrib
Rust	rust-sdk	rust-sdk-contrib
Swift	swift-sdk	ofrep-swift-client-provider
PHP	php-sdk	php-sdk-contrib
Ruby	ruby-sdk	ruby-sdk-contrib

For the latest SDKs and providers, see the OpenFeature ecosystem and the OFREP protocol spec.