BuildAlert is a direct-mail engine for the trades: browse UK planning applications free, then send branded letters to homeowners for £2 a letter, printing and postage included. SiteLens turns the same live planning register into a daily, trade-classified lead feed with estimated value bands, from £0 or £39/mo. Two tools, two jobs, and this page helps you pick the right one.
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BuildAlert is built around outreach: it auto-fills a homeowner's name and address, then prints and posts a branded letter for £2 a letter. SiteLens is built to tell you which applications are worth chasing in the first place, classifying every new UK application by trade and project type before you spend a penny on contact.
SiteLens reads every new application and tags it by trade, project type and an estimated value band, then emails the matches to you each morning, filtered to your area. BuildAlert offers filters and automation for sending letters, but it does not classify applications by trade or estimate project value for you, so the qualifying judgement stays manual.
BuildAlert charges per piece sent, £2 a letter or £2.50 a postcard, with monthly credit packs from £50/mo for 25 letters up to £500/mo for 250. SiteLens is a flat £39/mo, or £29/mo billed annually, for unlimited application views and daily alerts, plus a free-forever tier with no card. The costs scale very differently as your volume grows.
Feature-for-feature, based on publicly available information.
| Feature | SiteLens | BuildAlert |
|---|---|---|
| Core function | Planning-application lead alerts & classification | Direct mail to planning applicants |
| Built for | Construction supply chain | Trades running letter outreach |
| Public, transparent pricing | ||
| Free forever tier | No (browsing is free; sending is paid) | |
| Starting price | £0 · Pro £29/mo billed annually | £2.00 per letter (or £50/mo for 25 letters) |
| Send branded letters to applicants | Yes (£2 per letter, postage included) | |
| AI classification by trade & project type | ||
| Plain-English brief + estimated value band | ||
| Daily alerts filtered to your trade & area | Filters & auto-send, not a daily trade digest | |
| Map-based search | Postcode & radius filtering | |
| Unlimited application views | Yes (on Pro) | Yes (browsing is free) |
| Contract | Monthly or annual | Pay-as-you-go or monthly, cancel anytime |
For a trade running direct-mail outreach, the two fit together. Use SiteLens to find and qualify the work, with every new application classified by trade and value and pushed to you each morning, then use BuildAlert as the mailing house to post a branded letter to the applicants worth contacting. One tells you what to chase; the other puts the letter in the post.
BuildAlert publishes its pricing. Browsing planning applications is free, and you pay when you send: £2.00 per letter or £2.50 per postcard, with printing and postage included. Monthly credit packs run from £50/mo for 25 letters up to £500/mo for 250, advertised as saving around 30% versus pay-as-you-go. SiteLens is £0 on the free tier and £39/mo for Pro, or £29/mo billed annually, with unlimited application views.
No. SiteLens monitors and classifies live UK planning applications as a lead feed, with daily alerts, value bands and a saved-leads pipeline. It has no direct-mail features at all. If posting letters to applicants is the job you want done, BuildAlert is built for exactly that and is the better fit, and the two can sit side by side.
They do different jobs. BuildAlert is an outreach tool: it turns an application you've chosen into a printed, posted letter for £2. SiteLens is a qualification tool: it classifies every new UK application by trade, project type and estimated value, then alerts you to the matches each morning so you know which leads are worth chasing before you spend on contact.
Pick BuildAlert if the job you want done is the mailing itself. It auto-fills a homeowner's name and address, designs the letter, and handles printing, postage and tracking for £2 a letter, so you never touch an envelope. SiteLens does none of that, it does not send letters, postcards or any direct mail at all, so if outreach-by-post is your channel then BuildAlert is purpose-built for it.
BuildAlert also leans into the campaign side that SiteLens leaves to you: scheduled follow-up letters, QR business profiles, and a dashboard that tracks responses, jobs won and revenue from your mailings. If you measure success by letters out the door and replies in, and you'd rather pay only when you send, its pay-as-you-go £2-a-letter model is a fair fit, and that is a genuinely different job from the lead-finding SiteLens does.
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The £5,000/yr enterprise platform — without the sales call.
Read →Same daily UK planning feed — without the daily phone call.
Read →Same price, plus the map, classification, and analytics.
Read →Planning data for the supply chain, not letter campaigns.
Read →Live planning leads for the supply chain, not just land sourcing.
Read →Unlimited application views at £39/mo, not 25 views at £60.
Read →Planning leads for the trades, not site sourcing.
Read →Every council included, classified by trade and value.
Read →Construction leads from planning, not investment data.
Read →Planning-stage projects, not shared homeowner leads.
Read →Projects at planning stage, not pay-per-lead homeowner jobs.
Read →Find the projects, not just get listed for tenders.
Read →The 2026 NPPF reforms commit to 1.5 million new homes, mandatory targets, and faster decisions — expanding the pipeline for every trade.
Read: What the 2026 NPPF reforms mean for SME construction →