SourceTrace
Check the sources behind the claims on a book page
Photograph a page of a book, magazine or newspaper and see the sources behind each claim on it, including the ones that disagree.
Free on iPhone, iPad and the web. No account needed. Exports every source to Zotero, EndNote or BibTeX.
Example: tracing the claims on a page of A Short History of Nearly Everything
On the first claim below, two sources land on opposite sides: noaa.gov says “The pressure increases about one atmosphere for every 10 meters of water depth.”; hawaii.edu says “Seawater is about 800 times more dense than air.” The app shows you both and calls it Mixed support rather than picking a winner.
Water is about 1,300 times heavier than air, causing pressure to rise by the equivalent of one atmosphere for every ten meters (thirty-three feet) of depth.
“Seawater is about 800 times more dense than air.”
SourceTrace's reading: The claim says water is about 1,300 times heavier than air; this source says seawater is about 800 times more dense than air.
The pressure increases about one atmosphere for every 10 meters of water depth. At a depth of 5,000 meters the pressure will be approximately 500 atmospheres or 500 times greater than the pressure at sea level.
SourceTrace's reading: Supports the pressure-per-depth part of the claim but says nothing about water being 1,300 times heavier than air.
For every 10 meters of water, hydrostatic pressure increases by one atmosphere. At the average ocean depth (3,800 meters), pressure on the sea floor is a whopping 380 times greater than it is at the surface.
SourceTrace's reading: Supports the pressure-per-depth part of the claim but does not address the 1,300 times density ratio.
Because liquid water density does not change with depth, water pressure increases at a constant rate with increasing depth. From the previous paragraph, this means that water pressure increases by about one atmosphere (approximately 1000 mb) for every 10 meter increase in depth.
SourceTrace's reading: Supports the pressure-per-depth part of the claim but does not address the 1,300 times density ratio.
Because liquid water density does not change with depth, water pressure increases at a constant rate with increasing depth. From the previous paragraph, this means that water pressure increases by about one atmosphere (approximately 1000 mb) for every 10 meter increase in depth.
SourceTrace's reading: Supports the pressure-per-depth part of the claim but does not address the 1,300 times density ratio.
Of the thousands of exoplanets – planets around other stars – confirmed by our increasingly powerful telescopes, and despite extensive probing of the solar system, ours is still the only planet known to host life.
SourceTrace's reading: Directly supports the claim that Earth is the only known place in the universe that sustains life.
Six of the candidates in this zone ... size of Earth. A more recent study found that one of these candidates (KOI 326.01) is much larger and hotter than first reported. Based on the findings, the Kepler team estimated there to be "at least 50 billion planets in the Milky Way" of which "at least 500 million" are in the habitable zone. In analyzing which environments are likely to support life, a distinction ...
A research team led by the recipient of a U.S. National Science Foundation Faculty Early Career Development grant used computer simulations to determine that white dwarf stars have greater potential to host habitable planets than previously realized.
Anthony, Seb. "Astronomers estimate 100 billion habitable Earth-like planets in the Milky Way, 50 sextillion in the universe." Extreme Tech Crunch. April 4, 2013.
Answer (1 of 9): Earth is not the only planet that support life, there are others that support biological life forms different from ones on earth. Biological equivalent to that of human is also different on those planets. This is just a story until you read the following books to understand the n...
Both claims are from a page of A Short History of Nearly Everything by Bill Bryson. The search results were retrieved and scored by the app on 1 October 2026; each claim shows 5 of the 5 sources it returned, with nothing edited. Photographing the same page again can give a different verdict: on our test pages, a claim kept the same verdict in about three of four re-runs. Either way, every link comes from a search or a Wikipedia footnote, and every quoted passage is checked against its snippet.
What the verdicts mean
A verdict describes the evidence the app found, not whether the claim is true. “Mixed support” means the sources partly back this claim, or disagree about it: a reason to read them, not a ruling. Most claims in good nonfiction hold up; the interesting ones are where the sources part company. The app never writes a source: every link comes from a search or from a Wikipedia article's own footnote, and every quoted line is checked word-for-word against the search snippet it came from.
Who it's for
- Librarians. Every source exports to Zotero or EndNote (.ris) or to BibTeX, and each record notes the claim it was found for and whether the source supports it, contradicts it or neither. The page of A Short History of Nearly Everything above exports as 25 source records, plus one for the page itself.
- History teachers. Lateral reading, one claim at a time: students photograph a page and see what other sources say about each claim on it, including where those sources disagree. The app describes the evidence it found; the judgment stays with the class.
- Readers. Fact-check a striking number before you repeat it, and see which claims in a nonfiction book rest on sources you can open and read.
How it works
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Photograph the page. Or share highlighted text to the app from anywhere on your phone.
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The claims come out first. Each factual statement on the page, and whether the author cited anything for it.
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Well supported Contradicted Mixed support Inconclusive No relevant sourcesThen the sources arrive, claim by claim. Real search results — never invented — scored for how directly they bear on the claim, and for whether they agree with it.
Questions
- Does SourceTrace tell me whether a claim is true?
- No. Each claim gets a verdict that describes the evidence the search found (well supported, mixed support, contradicted, inconclusive or no relevant sources), not whether the claim is true. The sources are there to open and read; the judgment stays with you.
- Where do the sources come from?
- From a live web search (the Brave Search API), run for each claim. An AI model (Claude) reads the page, pulls out the claims and scores the results, but it never writes a source: every link came back from the search or from a Wikipedia article's own footnote, and every quoted line is checked word for word against the search snippet it came from. When a closely relevant result is a Wikipedia article, the app follows Wikipedia's own footnote for the claim and cites that source where it can.
- Can I export the sources to Zotero, EndNote or BibTeX?
- Yes. Every analysis exports as an .ris file for Zotero or EndNote, or as BibTeX. Each record notes the claim it was found for, whether the source supports it, contradicts it or neither, and the passage quoted from it. Sources are exported as web pages, and the app never fills in an author or date the search did not return.
- Is it free? Do I need an account?
- It is free on iPhone, iPad and the web, and works without an account.