[free pilot open to UK contractors, apply here]
KnockJoin the free pilot
[free pilot · UK contractors]

You did the work. Getting paid shouldn't be a second job.

Knock chases your unpaid invoices for you. Polite reminders go out on your behalf, replies come straight to you, and nothing is sent until you have approved it.

For small UK contractors who invoice other businesses.

drafting reminderawaiting approval

from: [owner name] via Knock

reply-to: you · copied: you

to: Sam, Greenway Property Services

re: invoice 1042 · £2,180.00 · 7 days overdue

Hi Sam, following up on invoice 1042 for £2,180.00, now 7 days overdue. Could you confirm a payment date this week? Thanks, [owner name]

[nothing is sent until you approve]
[due date]

Due

Invoice reaches its payment date

[day 1]

Friendly reminder

You approve, we send

[day 7]

Follow-up

Asks for a payment date

[day 14]

Final reminder

Clear and firm, still polite

[paid]

Reminders stop

The moment it is paid

[one invoice, from due date to paid. example: invoice 1042, £2,180.00, Greenway Property Services]

[why we exist]

Late payment costs small firms more than the money. Chasing gets put off, and the invoice gets older. Knock takes that job off you.

You did the work and sent the invoice.

The due date passed and nothing came back.

Most contractors would rather be on a job than writing a third email to a customer who has gone quiet.

£12,357

owed in late payments to the average UK small business, according to Hiscox

14

late payments a year, on average

~3 weeks

a typical late payment is settled after the due date

[source: Hiscox research, reported by ByteStart, 23 February 2026]

How it works

  1. [1]

    Send us your unpaid invoices

    Forward them or upload a list once a week. No new software to learn.

  2. [2]

    We draft the reminders

    Each message is written in your voice, with the invoice number, amount and due date.

  3. [3]

    You approve

    Read each one, edit it or skip it. Nothing goes out until you say so.

  4. [4]

    We send and track

    Reminders go out on schedule on your behalf. Replies come straight to you, and you are copied on every one.

  5. [5]

    It stops when you are paid

    Mark an invoice as paid and the reminders stop straight away.

The three reminders

[example messages. written fresh for each owner and customer]

[invoice 1042]

from [owner name] via Knock · to Greenway Property Services

Hi Sam, a quick note that invoice 1042 for £2,180.00 was due on 14 October. If it's already on its way, thank you. If not, could you let us know when we can expect it? Many thanks, [owner name]

Friendly reminder

[day 1]

A light check-in. Assumes it's on its way.

[7 days overdue]

from [owner name] via Knock · to Greenway Property Services

Hi Sam, following up on invoice 1042 for £2,180.00, now 7 days overdue. Could you confirm a payment date this week? Thanks, [owner name]

Follow-up

[day 7]

Direct. Asks for a date.

[14 days overdue]

from [owner name] via Knock · to Greenway Property Services

Hi Sam, invoice 1042 for £2,180.00 is now 14 days overdue and we haven't heard back. Please arrange payment by 4 November or call me on [phone] so we can sort it out. Thanks, [owner name]

Final reminder

[day 14]

Clear and firm. Still polite.

What you stay in control of

  • You approve every message before it is sent.
  • Replies go straight to you, and you are copied on every email.
  • You can pause or stop at any time.
  • Reminders stop as soon as an invoice is paid.

What we will never do

  • Contact anyone you haven't approved.
  • Send a message you haven't seen.
  • Threaten or harass your customers.
  • Sell or share your customers' details.

[your invoices]

See where every invoice stands

[example data. these are not real invoices]

knock.example / invoices

Good morning, [owner name]

[3 reminders need your approval]

Outstanding

£9,640

Overdue

£5,120

Awaiting approval

3

Paid this month

£6,300

invoicecustomeramountduestatus
1042Greenway Property Services£2,180.0014 OctFinal reminder due
1045Harlow & Reed Builders£1,640.0021 OctFollow-up sent
1047Marlowe Lettings£1,300.0028 OctAwaiting your approval
1049Northgate Facilities£4,520.0012 NovNot yet due
1038Kestrel Interiors£3,150.0030 SepPaid

[trust]

Why you can trust Knock

A registered UK company.
Knock is a trading name of Allheart Ltd, registered in England and Wales, company number 17507374. You can check us on Companies House.
A real person.
Run by Ansh Vora in London. Background in finance and venture, with an MSc from Queen Mary University of London.
LinkedIn
Plain terms.
The pilot is free. No contract. Leave whenever you like.
Your data.
We only use the invoice details you send us to prepare the reminders you approve. We use an AI service to draft them and an email service to send them. We don't sell your data.
Early, and honest about it.
We are running a small pilot with a few contractors so we can get this right. We would rather prove it works than promise that it does.

[free pilot]

Join the free pilot

We are working with a small number of UK contractors. The pilot is free for 6 weeks. In return, we ask for honest feedback, and for your permission to share anonymised results.

[week 0]
We load your unpaid invoices and agree how you want to sound.
[weeks 1 to 6]
You approve, we send, replies come to you.
[week 3]
A short check-in call to adjust the messages.
[week 6]
We review what got paid and agree what happens next.

[faq]

Questions