Supplier guide
You have a deadline. Here is the whole route, in order.
Registering as a supplier on eSourcing OS is free, takes a few minutes, and needs no card and no subscription. If you have arrived from a link on a Find a Tender notice, the buyer is running that competition on this platform, and everything you need to respond is here: the documents, the questions, the clarification channel and the submission itself.
The one thing worth knowing before you start is that email verification sits between registering and signing in, so register now rather than an hour before the deadline. Everything after that can be done in a single sitting.
If you are reading this at 4pm on deadline day
Register and verify first
You cannot sign in until you have clicked the link in the verification email. It is valid for twenty four hours and can be resent.
Open tender? Express interest.
On an open tender that click is what lets you start a bid at all. Without it there is no bid to submit.
Submit, then improve
A submitted bid can be amended and resubmitted while the tender is still open. A draft at the deadline is nothing.
Registration to submission
The sequence
Nothing here is optional except the clarification step, and skipping that one is usually a mistake. Read it once now and you will know what is coming before you hit it.
Register on the supplier portal
Complete the free supplier signup form: your name, email, company name, phone and address, whether you are an SME, a password, and the terms tick. Your Companies House number is optional but worth adding, because it is what matches you to any record a buyer has already created for your company. There is no card, no plan and no fee at any point.
Verify your email address
Registration ends on a "check your email" screen. You are not signed in yet. The verification link is valid for twenty four hours. If it has expired or the email has not arrived, request a new one from the same screen rather than registering a second time.
Sign in on the supplier portal itself
Supplier accounts sign in on the supplier portal address, not on the buyer side of the platform. If you land on the wrong one you will be sent across automatically. Use the link in the buyer email or the verification email and you will always arrive in the right place. Two factor authentication is optional and can be switched on later from your account.
Accept the invitation, if you were invited
An invitation email carries its own link that opens without signing in, showing the buyer, the reference, the title, the deadline and a masked version of the invited email address. Once signed in, press Accept. The invitation then binds to your company rather than to you personally, so colleagues at the same organisation can work on it too. Come back to the same link at any point; it is built to be re-entered after email verification interrupts the first attempt.
Open the opportunity and download the pack
Find it under Browse Tenders, searching on the title or the reference number from the notice. The tender page carries the description, the estimated value, the deadline, the commercial, technical and social value weightings, the buyer documents and the questions you will have to answer. Download the documents before you plan anything else, because the evaluation weightings tell you where the marks actually are.
Join the competition
On an open tender you must express interest before you can start a bid. It takes one click, it tells the buyer you are in, and you can withdraw it later provided you have not started a bid. On a restricted tender, accepting the invitation is what joins you. Neither is possible after the deadline has passed.
Ask your clarification questions early
Open a thread with a subject and a question, attaching up to ten files if you need to. Ask as soon as you spot the ambiguity rather than in the final week, because the answer may go out to every bidder and you want time to act on it.
Start the bid and draft your answers
Starting a bid creates a draft you can return to. The editor is tabbed: Questions, Social Value, Commercial and Documents. Answers save as you go, the price saves on its own, and a live word counter mirrors the limit the server will apply. Pressing start again reopens the same draft rather than creating a second one.
Upload your supporting documents
Files go straight to secure storage from the Documents tab, up to twenty five megabytes each, in the permitted file types. You can download your own uploads back to check you sent the right version, and delete and replace them for as long as the bid is still a draft.
Submit before the deadline
Submitting runs a final check: the deadline has not passed, every technical question is answered, every social value question is answered, a price is entered, and every word limit is respected. Anything outstanding is reported all at once rather than one problem at a time. When it passes, the status becomes submitted and the buyer is notified.
Invitations
What an invitation actually means
An invitation is an access grant, not a shortlisting decision and not an obligation. On a restricted competition it is the thing that makes the tender visible to you at all. On an open competition you do not need one.
The link in the invitation email carries its own token, so it opens without an account. Deliberately, it shows you very little: the buyer, the reference, the title, the deadline and a masked version of the invited address. No documents and no values are visible until you are signed in and have accepted, because until then the platform has no idea who is holding the link.
Accepting binds the invitation to your company, not to you. That is the detail worth understanding, because it is what lets a colleague pick the bid up when you are on leave. It also means an invitation cannot be moved to a different company once accepted, so if the buyer sent it to the wrong organisation, ask them to reissue it rather than forwarding it on.
Three ways you can be inside a restricted tender
Your supplier record is on the tender, your exact email address was invited, or your email address is on the same company domain as somebody who was invited. The third route is recorded when it is first used, so the buyer can see who from your organisation has access and remove it if they need to. If none of the three apply, the tender returns a not found page rather than a permission error.
Finding the opportunity
Search on the reference, not the title
Browse Tenders lists published opportunities across every buyer using the platform: the ones genuinely open to all, plus any restricted ones you have been invited to. Search matches the title or the reference, and the reference is the more reliable of the two, because titles get abbreviated in notices and reworded in emails. Each row tells you whether you are invited and whether you have already expressed interest.
Be clear about the scope, because it saves you looking for something that is not there. This platform publishes opportunities to Find a Tender; it does not collect opportunities from it. What you can see here are the competitions hosted here. It is not a UK wide opportunity feed, and there are no alerts or matching in the supplier portal. If that is what you are after, it is a different product and you can find it through the links in the portal sidebar.
Open the tender and read the weightings before you read anything else. The split between commercial, technical and social value is on the page, and it tells you where the marks are before you have committed a day to the wrong section. Every document you download is logged against the buyer’s audit trail, with which supplier took which file and when. That is equal treatment evidence rather than surveillance, and it works in your favour if a decision is ever questioned.
Clarifications
Ask early, and ask in writing
Clarifications live under Messages. You open a thread with a subject and a question, attach up to ten files if the question needs evidence, and the buyer replies in the same thread. Nothing important should happen by email alongside it.
A buyer can publish a thread, which broadcasts the question and answer to every supplier on that tender with your name replaced by “A supplier” and your attachments withheld. Expect that to happen to anything material. It is how equal treatment is maintained, and it is a reason to phrase the question so that publishing it does not reveal your approach.
After the enquiry deadline
The channel stays open
The messaging channel does not shut at the enquiry deadline, and it does not shut when the tender closes. It closes when the procurement is concluded. Whether you can post right now is shown on the page, with the reason if you cannot, so you are never typing into a box that is going to refuse you.
Reading is never switched off. The answers your bid was written against stay available to you after submission and after close, which matters if you are later reconciling what you were told against what you were scored on.
Preparing your response
Drafting, uploading, and the five checks at submission
Starting a bid creates a draft. You can leave it and come back, and pressing start again returns you to the same draft rather than making a second one. Once you submit, the draft locks: answers, price and document uploads are all refused while the bid sits in a submitted state.
The four tabs
Questions, Social Value, Commercial and Documents. Written answers save as you type them; the price is saved separately, so entering it is a deliberate act rather than something you can do by accident.
Word counts
A live counter mirrors the rule the server will apply. Limits are only enforced at submission, which means drafting long and cutting later never costs you work.
Files
Up to twenty five megabytes per file, in the permitted formats, uploaded straight to secure storage. You can download your own uploads back and replace them for as long as the bid is a draft.
What submission checks, in order
Everything outstanding is reported together, deliberately, so you are not sent back five times against a clock. When it passes, the status becomes submitted, the event is written to the buyer’s audit trail, and the tender owners get a notification and an email.
Changed your mind before the deadline? A submitted bid can be withdrawn, which tells the buyer, or amended, which reopens it as a draft for you to change and submit again. Both stop working once the deadline passes or the tender is no longer open, so if you amend at the last minute, leave time to press submit a second time. The safest pattern on a tight deadline is to submit something complete early and then amend and resubmit as you improve it.
After the deadline
What happens next, and when you hear
Evaluation happens on the buyer side. Bids are scored against the published criteria by named evaluators, scored question by question against the published criteria. You will not see any of that while it is happening, and silence during it is normal.
The outcome reaches you as a letter: award, unsuccessful, or disqualified. It arrives as a notification to every user at your company and as an email with the letter attached, and it carries your own commercial score, technical score and final score rather than a bare result. For above threshold procurements the buyer has to send those assessment summaries before an award can be made, under section 50 of the Procurement Act 2023, and an eight working day standstill period runs after the award before the contract can be confirmed. Weekends and bank holidays do not count towards it.
If you win and the buyer confirms the contract, you can see it in the portal with its dates, its value, its status and its KPIs. Be aware of the limit here: the supplier view of a contract is read only. There is no route for you to update a KPI figure, upload delivery evidence or submit an invoice, and the contracts page is reached from the buyer’s own notification rather than from the supplier navigation. Contract delivery reporting happens wherever your buyer already runs it.
Your company profile
Fill it in once
Company name and number, registered address and postcode, website, SME status, DUNS and VAT numbers, your PPON, your Central Digital Platform share code and your SSQ code. It takes ten minutes and it is the information buyers ask for repeatedly, so having it on file saves you time on the second bid and every one after it. Password changes and two factor authentication live on the same page.
Saving your share code works today. Automatic pulling of your details from the Central Digital Platform is not switched on yet, so nothing is filled in for you and nothing is verified against the register at this point. Save the code anyway and it will be ready when the pull arrives.
What the portal does not do
So you do not go looking
Before the tender exists
Market engagement is worth your time
Under Market Engagement you will find published pre-tender exercises: a buyer describing something they are thinking about buying and asking the market what is realistic. You can read the documents, download them, submit a response with up to ten files, and raise clarifications on the engagement itself.
This is the cheapest influence available to a supplier. A specification that reflects how the market actually delivers the service is written before the tender is published, not during it, and the suppliers who answered the engagement are the ones who shaped it. It also gives you weeks of notice on a competition that is going to appear with a short deadline attached.
Questions suppliers actually ask
Straight answers
Do I have to pay to register or to bid?
No. Supplier registration is free and bidding is free. There is no card, no subscription and no per tender fee at any stage, and there is no payment processing in the supplier portal at all. If you were expecting a charge because another portal charges one, there is nothing to look for here.
What happens if I miss the deadline?
You cannot submit. The deadline is enforced by the system, not by the buyer, and submission is refused once it passes. Expressing interest and starting a new bid are also refused after the deadline, and a bid left in draft is simply a bid that was never submitted. Aim to finalise a day early: the last hour before a public sector deadline is when file uploads and last minute rewrites go wrong.
Can I edit my bid after submitting?
Not directly, but you are not locked out either. While the tender is still open you can amend a submitted bid, which reopens it to draft so you can change it and submit again, or withdraw it entirely. Both are refused once the deadline has passed. If you amend, remember that it is the resubmission that counts, so leave enough time to press submit again.
I clicked the link on the Find a Tender notice and the page says not found. Why?
On a restricted tender, anyone who is not on the invitation list is shown a not found page rather than a locked page, so the existence of the competition is not confirmed to people outside it. The usual cause is being signed in with a different email address from the one the buyer invited. Sign in with the invited address, or use the link in the invitation email itself, which resolves without a session.
My colleague was invited, not me. Can I still get in?
Often, yes. Access is granted three ways: your supplier record is on the tender, your exact email address was invited, or your email is on the same company domain as an invited address. If you get in through the domain route the platform records it, so the buyer can see who from your organisation is taking part.
Will the buyer see my clarification question?
Yes, that is the point of asking through the portal. The buyer may also choose to publish the answer to every supplier on the tender, in which case your identity is replaced with "A supplier" and your attachments are not shared. You always see your own threads plus any thread the buyer has published.
The clarification deadline has passed. Can I still ask something?
The messaging channel stays open past the enquiry deadline and past the tender closing, and shuts only when the procurement is concluded. Whether you can post is shown on the page itself, with the reason if you cannot. Reading is never cut off, so the answers your bid was written against remain available to you afterwards.
Is there a word limit, and when is it checked?
Where the buyer has set one, yes. A live counter shows you where you are as you type, but the limit is only enforced when you submit, so drafting never throws away work you have not finished trimming. Every breach is reported in one go at submission rather than one at a time.
How big can my files be?
Twenty five megabytes per file, in the permitted formats, uploaded from the Documents tab of your bid. Up to ten files can be attached to a clarification message. Uploads and deletions are refused once the bid has been submitted, so make the document set final before you press submit.
How will I be told the outcome?
The buyer generates and sends an outcome letter: award, unsuccessful or disqualified. It arrives as a notification to every user at your company plus an email with the letter attached, and it carries your own commercial score, technical score and final score. For above threshold procurements the buyer must send those assessment summaries before an award can be made, and an eight working day standstill period follows the award.
Can I reuse answers from a previous bid?
Not inside the portal. There is no answer library or content reuse across bids here, so each submission is drafted from scratch or pasted in from wherever you keep your own material. Keep your own library of standard answers; it is the single biggest time saving available to a small bid team.
What is the Central Digital Platform share code field on my profile for?
You can store your share code, your PPON and your SSQ code on your company profile so a buyer has your verified references on file in one place. Pulling your details automatically from the Central Digital Platform is not switched on yet. Save the code now and it will be there when it is.
Stuck on a live deadline?
If something in the portal is not behaving and the clock is running, say so and tell us the tender reference. A question about the requirement itself belongs in the clarification thread, where the buyer can answer it and every bidder is treated the same.