Fathom Upgrade & Migration

Overview

Fathom is an AI meeting assistant that records, transcribes, and summarizes meetings. The API operates under

/external/v1

and exposes endpoints for meetings, transcripts, and action items. Tracking API changes is important because Fathom iterates rapidly on transcript schema fields (speaker attribution, sentiment data, highlight clips) and breaking changes to response shapes can silently corrupt downstream integrations that consume meeting data for CRM sync or analytics pipelines.

Version Detection

const FATHOM_BASE = "https://api.fathom.video/external/v1";

interface FathomVersionCheck {
  apiVersion: string;
  knownFields: string[];
  detectedFields: string[];
  newFields: string[];
  removedFields: string[];
}

async function detectFathomApiChanges(apiKey: string): Promise<FathomVersionCheck> {
  const res = await fetch(`${FATHOM_BASE}/meetings?limit=1`, {
    headers: { Authorization: `Bearer ${apiKey}` },
  });
  const data = await res.json();
  const knownFields = ["id", "title", "created_at", "duration", "attendees", "transcript_url"];
  const detectedFields = data.meetings?.[0] ? Object.keys(data.meetings[0]) : [];
  return {
    apiVersion: res.headers.get("x-api-version") ?? "v1",
    knownFields,
    detectedFields,
    newFields: detectedFields.filter((f) => !knownFields.includes(f)),
    removedFields: knownFields.filter((f) => !detectedFields.includes(f)),
  };
}

Migration Checklist

Review Fathom product updates for API changes and deprecations
Audit all endpoints referencing
```
/external/v1
```
in codebase
Verify meeting list response schema matches current field expectations
Check transcript endpoint for new speaker attribution fields
Validate action item extraction format (structured vs. plain text)
Update OAuth token refresh flow if auth endpoints changed
Test webhook payloads for meeting completion events
Verify pagination parameters (
```
cursor
```
vs.
```
offset
```
) are current
Update CRM sync mappings if meeting metadata fields renamed
Run integration tests against Fathom sandbox environment

Schema Migration

// Fathom transcript response evolved: flat text → speaker-attributed segments
interface OldTranscript {
  meeting_id: string;
  text: string;
  created_at: string;
}

interface NewTranscript {
  meeting_id: string;
  segments: Array<{
    speaker: string;
    text: string;
    start_time: number;
    end_time: number;
    confidence: number;
  }>;
  summary: string;
  action_items: Array<{ text: string; assignee?: string }>;
  created_at: string;
}

function migrateTranscript(old: OldTranscript): NewTranscript {
  return {
    meeting_id: old.meeting_id,
    segments: [{ speaker: "Unknown", text: old.text, start_time: 0, end_time: 0, confidence: 1.0 }],
    summary: "",
    action_items: [],
    created_at: old.created_at,
  };
}

Rollback Strategy

class FathomClient {
  private baseUrl: string;
  private fallbackUrl: string;

  constructor(private apiKey: string) {
    this.baseUrl = "https://api.fathom.video/external/v1";
    this.fallbackUrl = "https://api.fathom.video/external/v1"; // same base, version in path
  }

  async getMeetings(limit = 20): Promise<any> {
    try {
      const res = await fetch(`${this.baseUrl}/meetings?limit=${limit}`, {
        headers: { Authorization: `Bearer ${this.apiKey}` },
      });
      if (!res.ok) throw new Error(`Fathom API ${res.status}`);
      return await res.json();
    } catch (err) {
      console.warn("Primary endpoint failed, attempting fallback:", err);
      const res = await fetch(`${this.fallbackUrl}/meetings?limit=${limit}`, {
        headers: { Authorization: `Bearer ${this.apiKey}`, Accept: "application/json; version=legacy" },
      });
      return await res.json();
    }
  }
}

Error Handling

Migration Issue	Symptom	Fix
Transcript schema changed	Missing `segments` array, only flat `text` returned	Update parser to handle both old flat and new segmented formats
Webhook payload mismatch	`meeting.completed` event missing expected fields	Re-register webhook with updated event schema version
OAuth scope expansion	`403 Forbidden` on transcript endpoint	Re-authorize with updated scopes ( `meetings.read` , `transcripts.read` )
Pagination cursor invalid	`400 Bad Request` with cursor token	Switch from offset-based to cursor-based pagination if API changed
Rate limit headers changed	`429` without `Retry-After` header	Implement exponential backoff instead of relying on header

Resources

Next Steps

For CI pipeline integration, see

fathom-ci-integration

Claude-code-plugins-plus-skills fathom-upgrade-migration