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    Feature Flags & Config

    Ship dark. Flags live in Postgres as the source of truth and in Redis for sub-millisecond evaluation at the edge of every request. Percentage rollouts, user targeting, and a kill switch that does not require a deploy. This is how you survive a bad release on a Friday.

    1K – 1Musers supported
    $40 – $400/month infrastructure

    Architecture Diagram

    Interactive — hover over any node to see its role and description.

    AdminFlag ConsoleEnd UserAppPostgreSQLSource of truthRedisSnapshotPublisherUserFrontendAPIDatabaseCacheQueue

    Use Cases

    Gradual rollout of a new checkout or AI feature
    Per-tenant feature packs on a SaaS plan
    Kill switch for a failing LLM provider
    Simple A/B tests without a full analytics suite
    Config (limits, banners) without redeploying

    Technology Stack

    frontend

    React hooksNext.js

    backend

    Node.js / Laravel middleware

    database

    PostgreSQLRedis

    infrastructure

    ElastiCacheadmin UI

    Scalability Roadmap

    Stage 1One app users· Redis + table

    A flags table and a Redis key. Ship it in a week.

    Stage 2Several services users· Pub/Sub snapshot

    All services subscribe. In-process cache with short TTL backup.

    Stage 3Many tenants users· Segmented rules

    Rules by plan, tenant, and %. Evaluation stays O(flags) not O(users).

    Stage 4Global users· Regional Redis snapshots

    Postgres primary for writes. Redis snapshot per region. Kill switch replicates first.

    Cost Breakdown

    Development Cost

    $4,000 – $12,000 (2–6 weeks)

    Infrastructure Cost

    $40 – $400/month

    Maintenance Cost

    $400 – $1,200/month unless you later move to LaunchDarkly-class SaaS

    Security Considerations

    Only admins mutate flags; every change is audited
    Server-side evaluation for security-sensitive flags
    Client-exposed flags contain no secrets

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    Startup MVP Stack

    Launch-ready MVP in 6 weeks — modern, scalable, production-ready

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    Global Multi-Region SaaS

    Pin users to a region, keep Redis local, replicate the DB

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