Week 1 · FDE Mindset & Toolkit · about 3 minutes
What you will be able to do
Decide whether a change belongs in the core product or in one client's integration layer.
The idea
Dev is the product your company ships to every client. Delta is the code you write for one client: the adapter to their mainframe, their login, their odd schema. The words come from Palantir, where they name the people: Devs build the product, and Deltas are the forward deployed engineers who write this client code.
Keep the line hard. Client logic inside Dev turns every engagement into a fork, and forks never get upgrades. Delta talks to Dev only through its public API and configuration.
When you write the same Delta for a third client, that is a product gap. Take it upstream so it becomes a Dev feature.
# Lives outside the product repo.
from forge_sdk import Client, Transaction # Dev: public API only
def sync_ledger(rows: list[dict], forge: Client) -> int:
txns = [
Transaction(account=r["ACCT_NO"], amount=r["AMT_CENTS"] / 100)
for r in rows
]
return forge.transactions.upsert(txns)If the product needs a client's name in its code, the code is in the wrong layer.
Key takeaways
- Dev ships to every client, is configured, and is never forked.
- Delta holds one client's adapters, auth and pipelines, built on Dev's public API.
- Writing the same Delta a third time? Take it upstream as a feature.
Part of the Forward Deployed Engineer roadmap. New to the role? Start with what a Forward Deployed Engineer does.