Staleness-aware median pricing with source fallback

[Miracle656]

Background

A single price source can go stale or wrong. A median across sources with explicit staleness handling produces a robust price (distinct from a per-source confidence score).

What to build

Aggregate multiple sources into a median, drop sources older than a freshness threshold, and fall back through a priority chain when too few fresh sources remain — annotating which sources contributed and which were excluded for staleness.

Key files

• src/pricing/median.ts (new)
• src/api/rest.ts

Acceptance criteria

• Median computed only from fresh sources
• Fallback chain engages when sources are stale/missing
• Response notes included vs excluded sources; unit tests

Drips Wave · Complexity: Advanced · 200 points

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[smith961]

@smith961 has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

I would like to work on this issue

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[fadesany]

@fadesany has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hello maintainer, i would like to work on this issue

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[aboyejirebecca-prog]

@aboyejirebecca-prog has applied to work on this issue as part of the Stellar Wave Program's 6th wave.

Hey maintainer, I understand that this issue requires building a staleness-aware median pricing engine that filters out stale price sources before computing the median, engages a priority fallback chain when too few fresh sources remain, and annotates the response with which sources were included vs excluded.
My approach: create src/pricing/median.ts with a getMedianPrice function that accepts a freshness threshold (default 60s), filters sources by now - timestamp, computes a true median (not mean) on fresh sources only, and walks a configurable priority fallback chain when the fresh source count drops below the minimum. The REST layer in src/api/rest.ts will surface the annotated result including includedSources, excludedSources with staleness reasons, and a fallbackEngaged flag. Unit tests will cover fresh-only median, stale exclusion, fallback engagement, edge cases (even/odd source counts, all-stale, empty).
I have strong TypeScript experience and have shipped similar data aggregation logic in production. Happy to be assigned and can have a PR up promptly.

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[drips-wave]

Congratulations, @aboyejirebecca-prog! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on June 30, 2026.

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