Technology
4 Seasons runs construction work on its own software. One system holds each job's requirements, price, materials, qualified labor, schedule and proof, from the first photo to the final payment.
Each function below is marked with what runs today and what is in development. The examples are produced by the same code that prices and runs real jobs, using sample requests. They are marked as demonstrations and describe no real customer or job.
01
A request arrives as photos, a short video, a description, or a room scan from the phone app. The software reads it into a Work Spec, a structured description of the job with its scope lines, quantities, the parts each line needs, the checks that will prove it was done, and the questions that would narrow the price. Every line records which photo or sentence it came from and how sure the read is.
Who decides
The software only fixes a price when its read is calibrated above a set confidence. Below that it asks for another photo or prices a visit first. Kitchens, structural findings and signs of hidden damage always go to a visit with a person.
Work Spec compiled from a sample request
Example
ws_example0000000001 · 4s.work/v2 · rev 1 · 30307
Replace a tank water heater and 1 more
Licensed technician (plumbing license) · read 86% sure · fixed price
Replace a tank water heater
$2,195
Place a leak sensor
$79
Total
$2,274
Evidence photo and transcript · 4 parts · held 24 h
02
Listed repairs are priced from a published price list. Remodels are priced from a package price book on the room's size, and the price becomes fixed once the room is measured. When the scope is uncertain, the estimate is a range, and the software lists what moves it and which question would narrow it most.
Who decides
An estimator reviews every non-standard remodel and sets the final price. In the Estimator, a model reads the inputs into scope and never sets a number; quantities, rates and prices come from the price book and are shown with their source.
Price range for a sample request
Example
Price range · 2 lines
$455 to $640
Expected $495. Low is the 5th percentile, high the 95th.
What moves it
Unsafe wiring in the box that has to be corrected (4% chance)
± $450
Whether this is needed: Replace an outlet with a GFCI (45% sure)
± $310
A seized shut-off valve that has to be replaced (12% chance)
± $185
Whether this is needed: Fix a running toilet (55% sure)
± $145
First questions, by how much each narrows the range
Is this the work: Fix a running toilet?
$76
Do the shut-off valves under it turn easily and look clean, with no green or white crust?
$38
Is this the work: Replace an outlet with a GFCI?
$34
03
Start dates come from crew calendars, so a date offered online is one a crew can keep. Each Work Spec carries the order its steps must happen in, including cure times, licensed sign-offs and inspection lead times, and the earliest day each step can start. Work is offered only to crews and pros whose recorded skills and licenses cover every line.
Who decides
A crew or pro accepts or declines each offer. Staff assign anything the matching cannot fill.
Step order of the sample Work Spec
Example
ws_example0000000001 · 2 working days · critical path 3 steps
Replace a tank water heater
Licensed sign-off: Replace a tank water heater
Place a leak sensor
Inspection: final plumbing
04
Every priced job has a bill of materials, generated from the bathroom's configuration or from each repair's parts list, with quantities from the measurements and the step each part is first needed at. The purchasing software drafts supplier orders, holds each one until the latest day it still arrives in time, and compares sources on their landed cost and arrival date.
Who decides
A person approves every overseas order, and the cash check refuses one that would take the balance below its floor. Orders to local branches without an account on file are placed by staff.
Parts by step for a sample bathroom
Example
B02-1221111 · G23-P01-E07-S01 · F07 · 30309
20 parts in 11 totes
Hall bath, 8 × 6 ft, built 1984
01 · Protect the home and demo
1 parts
02 · Plumbing rough-in (licensed)
1 parts
03 · Electrical rough-in (licensed)
3 parts
04 · Backer board and waterproofing
2 parts
05 · Shower or tub and walls
3 parts
06 · Floor
1 parts
07 · Paint
1 parts
08 · Vanity, toilet, glass and storage
5 parts
09 · Plumbing trim-out (licensed)
1 parts
10 · Electrical trim-out (licensed)
1 parts
11 · Clean, punch list and walkthrough
1 parts
05
The crew app shows each job as a sequence of steps, with the parts for each step and the photos each step needs before it counts as done. The homeowner can follow arrival and progress. When a crew finds something unexpected, such as hidden damage, it is recorded as an exception with priced options for the homeowner to choose from.
Who decides
The homeowner decides any change to scope or price. The crew lead decides how the work is done within the written standard for each step.
Crew steps for a sample bathroom
Example
B02-1221111 · G23-P01-E07-S01 · F07 · 5 days · crew of 3 · 27 photos · 2 inspections
Protect the home and demo
Plumbing rough-in (licensed)
Electrical rough-in (licensed)
Rough-in inspection
Drywall and patch
Backer board and waterproofing
Shower or tub and walls
Floor
Paint
Vanity, toilet, glass and storage
Plumbing trim-out (licensed)
Electrical trim-out (licensed)
Clean, punch list and walkthrough
06
Each step has written acceptance checks, and each check names the proof it takes, which is a photo, a video, a measurement against a range, or a device reading. Photos are hashed when they arrive, so any later change to a file would show. Gas, water pressure and electrical work is signed off by the licensed pro. The system is built to seal a signed Work Record of each job, listing every step, its proof, who did it and how it was judged.
Who decides
People accept the work. The software flags a photo that does not show its check, and reviewers decide. Safety work is never approved automatically.
Acceptance checks of a sample line
Example
ws_example0000000001 · s1 · water-heater-replace
Replace a tank water heater
7 acceptance checks from the written standard
The old heater in place and its rating label
photo
The new heater, its pan, relief pipe and connections
photo
The new rating label, serial readable
photo
Relief valve piped to a safe place
photo
No leaks at the connections after 10 minutes
photo
Hot water at the farthest faucet
photo
Gas venting, clearances and the seismic or expansion items per local code
photo
Hot water at the farthest tap at the set temperature
110 to 125 °F
The functions above sit in a larger operating model. Information passes from each layer to the next, and the outcomes of finished work return to planning. Each layer is marked with what runs today.
01
Homeowners, property managers and business customers.
Homeowners in metro Atlanta request work online with photos, video or a description, or book a listed repair at a fixed price. Programs for property managers and businesses are being built.
Passes on, A request with its photos, video frames, words, address and any measurements
02
Requests turned into scopes, pricing, materials and procedures.
The spec compiler reads the request into scope lines from the catalog, with quantities, parts, labor by skill and license, the order of steps, the acceptance checks and a price or a price range.
Passes on, A Work Spec with scope, quantities, parts, required skills and licenses, step order, checks and price
03
Qualified professionals and trained workers assigned to appropriate work.
Each scope line names the skills and licenses it requires, and work is offered only to crews and pros who hold them. Our own crews do the work today. The independent network and the Academy are being built.
Passes on, An assignment with the crew, the arrival window, the steps and the proof each step needs
04
Materials sourced, standardized and prepared.
Each job's bill of materials becomes draft supplier orders, timed to arrive before the step that needs each part and compared on landed cost and arrival date.
Passes on, Parts for each step, ordered to arrive before that step starts
05
Work executed through coordinated field operations.
Crews work from the crew app, step by step, with the parts and the required photos for each step. Unexpected conditions are recorded as exceptions with priced options.
Passes on, Proof for each step, with photos hashed on arrival, readings and the parts installed
06
Completion evidence, inspections and warranty records.
Each step's proof is checked against its written acceptance checks and reviewed by people. Permits and inspections are tracked against the steps they cover, and the warranty is recorded against the home. Sealing a signed Work Record for every job is in development.
Passes on, A Verified Work Record with each step's proof, verdict, executor, license, materials, permits and inspections
07
Outcomes inform future planning, labor estimates, materials selection and procedures.
Cost per verified outcome is measured for each kind of job from the ledger. Finished visits calibrate how photo reads are trusted. Learning production rates and waste from closed jobs is in development.
Returns to planning,
Project Engineering, Workforce, Procurement
Finished work updates the numbers planning runs on. Photo reads are calibrated against what visits found, production rates and waste can move toward what closed jobs took, each pro's verified record feeds matching, and supplier on-time rates are measured from receipts. Learned numbers move only inside set limits and after a minimum number of records.
Each job produces a Verified Work Record in the format 4s.work-record/v1. It lists every step, who did it and under which license, the SHA-256 hash of every proof file, the verdict and the rule version it ran under, the materials with lots and purchase orders, installed equipment with serial numbers, change orders, permits and inspections, and whether each step's pay was released.
The record is serialized in a canonical form, with keys sorted at every level and no whitespace. Its content hash is the SHA-256 of that form, and an Ed25519 signature covers the hash together with the record's id, sequence, time and the reason it was sealed. A changed field fails the hash, and a re-hashed edit fails the signature.
Pay amounts, material costs, the homeowner's contact details and photo locations are left out, so a homeowner can share the record with a buyer, an inspector or an insurer. Anyone can check a record at the public verify endpoint or offline with the published key.
Canonical form and content hash, computed with the production functions
Example
As recorded
pass{"outcome":"Shower valve set to depth","proof":[{"sha256":"75947f179f156f5411eeaab75e233f6899b2f50cc99e975f176d39b8757a3040","shot":"valve-depth"}],"ref":"step:example-1","verdict":{"by":"person","result":"pass"}}sha256:a34ffbf768ceceacce4b67bc234e097bd84a7edaef71c05e91ee897c1e4e3714
One word changed
fail{"outcome":"Shower valve set to depth","proof":[{"sha256":"75947f179f156f5411eeaab75e233f6899b2f50cc99e975f176d39b8757a3040","shot":"valve-depth"}],"ref":"step:example-1","verdict":{"by":"person","result":"fail"}}sha256:39c779fa1e2f21875e238fa10e0c594523973a6444984d9dbda1aa4f512fbc50
Every rate, threshold, window and fee the workflows use is a named, typed setting in one registry, with its unit, its allowed range and its starting value. Code reads each setting at run time rather than carrying the number as a constant.
Some settings are learned from our own records once there are enough of them, shrunk toward the prior so a few records cannot swing them. The rest are set by the owner, with a reason, and every change is audited with its old and new value.
A few switches are owner-only, such as whether live settlement money moves and which pricing model customers see. The values themselves are internal and are not published.