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Series · 7 parts Published July 20, 2026

Offer letter generator

A small system that turns an agreed offer into a letter from your own approved template: the terms come from a short form, the wording comes from the template, and anything that does not fit a template clause stops and asks. It never invents a term and never sends without a person reading it. Seven posts on the same system — one diagram at a time — with a cost breakdown and an engineering reference at the end.

  1. 01

    An offer letter generator on AWS for a few dollars a month

    The whole system on one page — a terms form, a clause matcher and a drafter — with one hard rule: it never writes contractual wording.

  2. 02

    How the agreed terms get captured

    A nine-field form, a note lane for the people who will never use a form, and the small set of fields that must never be inferred from anything at all.

  3. 03

    How a term finds its clause

    How nine fields map onto approved wording, why the clause library holds a small set of exact options rather than free values, and which variables are safe to substitute.

  4. 04

    How an unusual term stops the draft

    Why an unmatched term is a hard stop rather than a warning, what the request for new wording looks like, and how an approved clause enters the library permanently.

  5. 05

    How a sent offer is recorded

    What a sent offer keeps, how acceptance is recorded, the handover to onboarding, and the one report that says whether the clause library is keeping up with the business.

  6. 06

    What the offer letter generator costs

    About $1 a month. One Bedrock read per offer is the only line that grows; the queue, the table, the mail and the storage are rounding errors. Plus the three ways the bill could surprise you.

  7. 07

    Engineering reference: the offer letter generator architecture

    Same system, drawn purely for engineers. Service names, region, Lambda inventory, IAM scopes, the schemas and the exact model id.

What is an offer letter generator?
A small serverless system that fills your own approved offer template from a short form of agreed terms, flags anything the template does not cover, and puts a draft in front of a person to send. It never writes contractual wording of its own.
Does a model write the letter?
No. The wording is your template, approved by whoever approves such things. A model is used in exactly one place: reading a free-text note about what was agreed and turning it into form fields, which a person then checks.
What happens with an unusual term?
It stops. A term with no matching template clause — an unusual notice period, a bespoke bonus, a relocation arrangement — is flagged and the draft is marked as needing a clause somebody writes. The system never improvises contractual language.
Does it send the offer?
No. It produces a draft and tells the hiring manager it is ready. Sending an offer is a decision with legal weight, and the send button belongs to a person.
What does it cost to run?
A couple of dollars a month. Offer volume is low even in a business that is growing. See part six.
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