Direct answer
Start now, the purchase order will follow: start, but start limited.
The client is in a hurry, procurement is slow, and your contact says the sentence every freelancer hears before the trouble starts: start now, the purchase order will follow. Sometimes it does. Sometimes the PO dies in an approval queue, the contact moves teams, and the work you did on a promise gets repriced as a favor. The answer is not to refuse and lose the job, and it is not to start wide open. It is to start limited: the instruction in writing, a cap on the start, a date for the PO decision, and a record of every step. Here is the pattern, step by step.
Updated October 26, 2026.
The risk: work started on a promise is work priced by the client later
A purchase order is not paperwork for its own sake. It is the moment the client company, not just your contact, commits to the job at a price. Work done before that moment runs on one person's word, and one person's word has a half-life: people change roles, budgets freeze, and the person who said start is rarely the person who later asks why an invoice exists for a job with no order number. None of that makes your contact dishonest. It makes the promise fragile, and fragile promises need structure, not trust falls. The structure below takes one short reply to set up and never insults the client, because it reads as professionalism, not suspicion.
Step 1. Get the start instruction in writing, with a name on it
Before the first hour, get one written instruction: who is asking you to start, what exactly to start, and that the PO is in process. An email or a message thread is enough. You are not asking for a contract; you are asking for the sentence your contact already said out loud to exist where both of you can point at it later. If the contact will not write it down, that is your answer about the promise, and the start waits. Note the name and the role: an instruction from the person who will own the delivery carries weight that a relayed instruction from someone else's meeting does not.
Step 2. Cap the start: scope, hours, and a PO decision date
Agree the limited start in the same thread: the first stage only, a cap in hours or days, and the date by which the PO decision lands. "I will start stage one, capped at ten hours, and we will check on the PO together on Friday" is a complete limited start. The cap does two jobs. It bounds your exposure if the PO dies, and it creates a natural decision moment where the client either converts the start into an order or watches the work pause, which concentrates minds in procurement wonderfully. Work past the cap without an order is a new decision, never a drift.
Step 3. Receipt every step from the first hour
From hour one, keep the record you would want if this is disputed in six months: the instruction, the work as it runs, and the delivery states. When the work runs through Zambo, every call carries a verifiable receipt under AER-1, published as IETF Internet-Draft draft-zambo-aer1-26, so what was done, when, and what it produced is checkable by anyone you hand the record to. A receipt proves the saved result was not changed since it was saved. It does not prove the answer was right, and it does not replace the written instruction; together, the instruction says the work was ordered and the receipts say the work happened. That pair is the whole defense. New users get 20 free calls per day, then they upgrade when the job needs more.
Step 4. At the cap, stop or convert
When the cap arrives, the limited start ends, cleanly, one of two ways. The PO lands and the work continues under the order, with the early hours folded in as stage one. Or there is no PO yet, and the work pauses while the client decides, stated plainly and without drama: "Stage one is complete at the cap we set. I will hold here until the PO lands, then continue the same day." Pausing at a cap you both agreed is not a threat; it is the agreement working as designed. The clients worth keeping respect it, because it is the same discipline they would want from anyone spending their budget.
Step 5. If the PO never comes, invoice against the accepted record
Sometimes the PO dies: the project is cancelled, the budget is pulled, the sponsor leaves. Work done inside a written, capped start instruction is still ordered work, and it is billed as such: the instruction, the record of what was delivered inside the cap, and the invoice for exactly that scope, sent together. Send the sequence, not an accusation. Most authorization disputes are memory disputes, and a dated record ends them faster than any argument about who said what in a call. If the client refuses to pay for work their named contact ordered in writing and they received, that refusal is information about the next job, and it arrived at the cost of one capped stage instead of the whole project.
Copy-paste: the reply that starts the work and protects it
Happy to start right away. So we are both covered while procurement runs: I will start stage one today, capped at [hours] hours, and receipt the work as it runs so you can see exactly what is done. Can you confirm this thread as the start instruction, and tell me the date the PO decision lands? At the cap I will pause and check in; the moment the PO arrives I continue the same day.
What a record does not settle
A verifiable receipt proves the saved result was not changed since it was saved; it does not create a purchase order, does not bind a company whose own rules require one, and cannot make a client pay. The written start instruction, the cap you both saw, the decision date, and the dated record of the work are what the conversation stands on. This page is general information, not legal advice.
Frequently asked questions
Client says start now, the purchase order will follow. Should I start before the PO arrives?
Start, but start limited. Get the start instruction in writing, from a named person, with the scope, a cap on hours or days, and the date the purchase order decision lands. Receipt every step from the first hour. If the PO arrives, the early work folds into the order. If it never arrives, the written instruction and the dated record of the work are what you invoice against, and they are the difference between a payable bill and an argument about a favor.
The PO never arrived and the client says the work was never authorized. What do I do?
Send the sequence, not an accusation: the named person's start instruction, the capped scope you both saw, the dated record of the work delivered inside that cap, and the invoice for exactly that work. Authorization disputes are usually memory disputes, and a written instruction plus a checkable work record ends most of them. Pause any further work until a decider confirms, in writing, how the next stage gets ordered.
Will asking for the instruction in writing make me look difficult?
No. It reads as the way professionals start urgent work, and it protects your contact as much as you: if their own management later asks who authorized the start, the thread answers for them too. The difficult version is the dispute six months later, when the promise is a memory and the invoice is real. One short reply now is the cheapest goodwill either of you will ever buy.