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  3. Test Ad Injection Locally in Flask

How-to guide

How to Test Ad Injection Locally in Flask

This guide shows how to test ad injection locally in a Flask app, the goal being to run injection against a local/non-SSL server during development. It builds on the Monetzly gRPC service (no Python SDK exists for this stack), so the approach is specific to how Flask produces and streams responses.

Overview

You can develop ad injection for a Flask app locally before going to production. Point the SDK at a local ad-server address and turn SSL off; everything else — the injection call, session context, fallback — behaves the same as production.

This lets you verify that your Flask stream flows through injection and reaches the client correctly without needing production credentials wired up.

Flask apps are usually built for simple LLM web apps, chat endpoints, and prototype APIs, so test ad injection locally typically comes up while a user is mid-conversation, the moment where monetization has to be additive rather than disruptive.

How this works on Flask

Same as FastAPI: no Python SDK, so integrate via the shipped tps_alter.proto gRPC service (generate stubs, drive ProcessStream) or a Node sidecar. In Flask, stream the injected tokens back with a generator response. Confirm the non-JS auth handshake before publishing.

Since Flask is a Python stack with no official SDK, this task runs through the shipped tps_alter.proto gRPC service (or a Node sidecar); the auth handshake for a direct client is still TODO_VERIFY.

Steps

  1. Set the server address to your local host (e.g. localhost:8080) and disable SSL.
  2. Run your Flask app and send a test prompt through the injection path.
  3. Confirm tokens stream to the client, then switch to your production host and SSL for release.

Integration snippet

TODO_VERIFY: Flask uses the gRPC proto path, confirm the auth handshake with Monetzly before relying on this in production.
# Generate stubs once from tps_alter.proto (shipped in @monetzly/server-sdk):
#   python -m grpc_tools.protoc -I. --python_out=. --grpc_python_out=. tps_alter.proto
# Then drive TPSAlterService.ProcessStream: StartRequest -> TokenRequest* -> StopRequest,
# reading back injected TokenResponses. See the FastAPI page for the full bidi loop.
# In Flask, yield the injected tokens from a streaming Response.
# TODO_VERIFY: auth handshake (API key placement) for a direct gRPC client.

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