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, Pro £29/mo billed annually (£39 monthly). 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 application across 380+ UK councils 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 £29/mo billed annually (£39 monthly) 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 | Included | Included |
| Free forever tier | Included | No (browse free, send paid) |
| Starting price | £0 · Pro £29/mo billed annually (£39 monthly) | £2.00 per letter (or £50/mo for 25 letters) |
| Send branded letters to applicants | No (postal export for your own mail run, Pro) | Yes (£2 per letter, postage included) |
| AI classification by trade & project type | Included | Not included |
| Plain-English brief + estimated value band | Included | Not included |
| Daily alerts filtered to your trade & area | Included | Filters & auto-send, not a daily trade digest |
| Map-based search | Included | Postcode & radius filtering |
| Unlimited application views | Yes (every plan, including free) | 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 gives unlimited application views on every plan, including free. Pro is £29/mo billed annually, or £39 monthly. Figures are from BuildAlert's own site as at August 2026.
SiteLens does not print or post letters for you. What Pro does include is a postal export: applicant names and site addresses for the applications you choose, formatted for a mail run, with a reminder to screen against the Mailing Preference Service before you send. So you can post your own letters for the price of a stamp, or pair SiteLens targeting with BuildAlert fulfilment. If you want the printing and posting handled end to end, BuildAlert is built for exactly that.
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 application across 380+ UK councils 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 not print or post anything for you: Pro gives you a postal export of applicant names and site addresses for your own mail run, and the rest is your envelope and your stamp. If hands-off outreach-by-post is your channel, 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 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 →Whole-UK coverage from £29/mo billed annually, plus the map and classification.
Read →Planning data for the supply chain, not letter campaigns.
Read →Live planning leads for the supply chain, where SearchLand does land sourcing.
Read →Unlimited application views on every plan, not 25 at £60.
Read →Planning leads for the trades, not site sourcing.
Read →Every council included, classified by trade and value.
Read →Leads for your trade, not alerts about your neighbours.
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 →Reach the project before it reaches a tender list.
Read →The 2026 NPPF reforms commit to 1.5 million new homes, mandatory targets and faster decisions. That widens the pipeline for every trade.
Read: What the 2026 NPPF reforms mean for SME construction →