Konvertera.nu
Unit and school-data conversion, in Swedish and English. The reference data is generated from open sources and stays current without anyone editing a page.
Products
What I build when nobody is paying me
My own products and free tools. The products are live sites I built and still run.
Formelsamling.se
Upper secondary maths, physics and chemistry, one page per formula, each with its variables, units, a worked example and the mistakes that are easy to make. The site is in Swedish.
237 formulas
Valutakurs.nu
Daily krona exchange rates from Riksbanken going back to 1993, with the rate for any date, averages for the books, and a tool that compares what a bank charged on a card payment abroad. The site is in Swedish.
Utland.se
An independent guide for Swedes buying a home abroad: what the purchase really costs, country by country, with a calculator for the taxes and fees and a source and a last-checked date for every figure. The site is in Swedish.
Tools
Free, and they run entirely in your browser.
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Eval-set inspector
Check an eval set before you trust a number that came out of it: row counts, field coverage, duplicate prompts and length spread, all read in your browser.
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Eval-set leakage inspector
Compare the splits of an eval set and see which prompts appear in more than one. Reports the overlap it finds, with the rows on each side, and never claims that finding none proves there is no leakage.
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LLM JSON repairer
Paste model output that is almost JSON and get back a document that parses, with every character that changed listed line by line. Nothing is repaired quietly.
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MCP server inspector for the whole tools/list
Paste an MCP tools/list answer and get an exact report: two tools described the same way, names that collide once case is ignored, one enum spelled two ways, plus ten per-tool schema checks. Runs in your browser, nothing is uploaded.
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Message-format converter
Paste a conversation in OpenAI, Anthropic or Gemini shape and get it back in another. Every construct that could not be carried across is named rather than dropped.
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SSE stream reassembler
Paste a raw streaming response and get the message back, the tool calls rebuilt delta by delta, and the point where the stream stopped. A cut-off stream is labelled as one, never handed back as a finished answer.
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Tool-schema linter
Paste a function-calling schema and get the ten things that actually break tool use, such as a parameter with no description or a required field that does not exist. Each finding says what goes wrong when a model meets it.
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Trace redactor
Strip API keys, tokens, emails, phone numbers and IPs from a transcript before you share it. Placeholders are stable, so it still reads as a conversation. The original never leaves this page.
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