RASP UK is irreplaceable. Here is where Convek fits alongside it.
RASP UK has been the soaring forecast for UK pilots for two decades, run by volunteers, free, brilliant. Convek is not trying to replace it. Here is what we actually do differently.
I want to start this one as plainly as possible. RASP UK is irreplaceable, the volunteers who keep it running deserve more recognition than they get, and Convek is not trying to replace it. If you are a UK pilot reading this and you have been using RASP UK to plan flights for years, keep using it. That is the right tool for that job and nothing in this post should be read as a pitch to switch.
The reason this post exists at all is that 'Convek vs RASP UK' is a comparison that lands in my inbox often enough that it deserves a public answer rather than a private one. Both products are in the same lineage - both run regional WRF integrations, both produce RASP-style derived fields, both forecast thermal strength and cloudbase and soaring height. So the question 'why is there a second one' is fair.
The product shapes are different. RASP UK is a free, web-rendered, pilot-facing forecast site, maintained by volunteers, hosted on best-effort infrastructure, with no API, no SLA, and an explicit non-commercial use policy. That shape has served the UK soaring community brilliantly for two decades and is, in real terms, one of the most valuable pieces of community infrastructure the sport has. The whole thing exists because a small number of people care enough to keep it running, and the result is that every UK glider and paraglider pilot has access to a serious soaring forecast for free. That is genuinely remarkable.
Convek is a paid, supported, API-shaped product. We run our own WRF integration on the same class of physics (YSU PBL, WSM3 microphysics, Noah land surface), serve the output as structured JSON, run four cycles a day on a managed schedule, and offer commercial redistribution rights and an SLA. The model overlap with RASP UK is real and intentional - we are in the same scientific lineage. The product overlap is not real - we are aimed at developers, clubs, and instrument makers who need data they can build on, not at individual pilots who need a forecast to look at in a browser.
Where the two answer the same question, RASP UK is the right answer for the cost. If you can get the data you need by looking at a rendered map, and you do not need uptime guarantees, and your use is non-commercial, the volunteer service does the job. That is a lot of cases.
Where Convek fits is the cases the volunteer service is not built for. Building a commercial paragliding app and shipping it to the App Store. Wiring a club website widget that has to stay up reliably during a competition weekend. Pulling forecast values into a vario or instrument firmware. Integrating soaring data into a flight-planning tool with paying users. Any of those needs uptime, support, redistribution rights, and a contract - which is what the paid tiers provide. The side-by-side comparison breaks this down field by field.
There is also a coverage point worth noting. RASP UK is UK-only by design - it serves the UK pilot community and that is the brief. Convek covers UK, Switzerland, Slovenia, Austria, Czechia and Germany at 4 km today. A developer shipping a multi-country app cannot build on a single-country forecast even if the single-country forecast is excellent.
If you fly in the UK, RASP UK is part of why UK soaring is what it is. Use it, donate if there is a donation page, thank the volunteers when you see them. If you are building something that needs more than a free best-effort web forecast can give, Convek is the layer above it that exists to handle that specifically.