Turn Reddit complaints into SaaS ideas with Claude and the TrendsFast MCP

Why start from complaints

An idea that starts from a problem people already describe in public has one thing a brainstormed idea lacks: someone, somewhere, said it hurt. The Customers product returns exactly that kind of evidence: conversations where people like your customers describe a problem, ask a question or request something. It reads Reddit, X, Hacker News and GitHub. What it cannot tell you is whether anyone would pay; that is the question this workflow ends on, not one it answers.

1. Connect TrendsFast to Claude

Create an API key in the dashboard under Add to your agent, set it as TRENDSFAST_API_KEY in your shell, and add the server to Claude Code in a folder of its own:

mkdir saas-ideas && cd saas-ideas
claude mcp add --transport http trendsfast https://trendsfast.com/api/mcp/v3 \
  --header "Authorization: Bearer $TRENDSFAST_API_KEY"

The Claude apps can use the custom connector instead, where your Add to your agent page offers it. Your project’s confirmed context decides which communities are read, so check that it names the audience and subreddits you care about before the first call.

2. Ask for problems, not ideas

Ask for the grouping first and the ideas last. A model asked straight for “SaaS ideas” invents demand; asked to group cited threads, it can only work from what the result contains.

Use TrendsFast. First read my project context and my credit balance (both free).
Then run one Customers call (trendsfast_niche_trends with product "customers"
and my context_id), with max_credits 10 and a request_id you keep.
From the items that state a problem, a question or a request:
1. group them by the problem they describe, in the posters' own words;
2. for each group give the thread links, dates, scores and comment counts;
3. say which groups are one-off and which recur across two or more threads;
4. for the two strongest groups, propose a small product that solves the problem,
   who pays for it, and the one question I must answer before building it.
Do not call anything trending or growing unless the result measured it.
Only titles and counts are retained: tell me which threads to open and read first.

3. Keep the spend bounded

• The Customers call costs 10 credits and collects your communities fresh first. max_credits is a ceiling: a call whose quote is above it is refused with CREDIT_QUOTE_EXCEEDS_LIMIT before anything is charged.
• Keep the request_id. Sending the same one again replays the saved result instead of paying twice, and trendsfast_read_result rereads or pages it for free.
• A follow-up question with trendsfast_ask_trends costs at most 5 credits and answers from saved evidence only; an answer with no findings costs nothing.

What a useful answer looks like

Illustrative, not real output: for a niche of small B2B software teams, a useful answer reads something like this.

1. Recurring: usage costs that run away. Three threads in one week, each with its link, date and counts, describing a bill that grew overnight.
2. One-off: a single question about business email pricing, kept but not developed, because nothing else in the result repeats it.
3. Proposal: a spending alert for teams that resell model usage, paid by the team that carries the bill. Question to answer first: do they already watch this in their provider’s dashboard?
4. Not shown by the evidence: whether the problem is growing; the result had no earlier window to compare with.

Evidence and limitations

• Only titles, links and counts are retained. Open every thread you build on and read the discussion before you trust the summary.
• A score or comment count says a thread drew attention, not that the problem is common or that anyone would pay to solve it.
• Coverage is what your result reports. A platform marked not collected is unknown, not quiet.
• TrendsFast does not post or reply anywhere. Anything you publish, you publish.

When this is not the right approach

• Your buyers do not discuss their problems in public, as with most enterprise purchases.
• You already have customers to interview: twenty minutes with one of them beats a week of public threads.
• You need search demand first: start with the content opportunity finder or a search tool, then come back for the conversations.