diff --git a/src/cache.ts b/src/cache.ts
index b40e0ff..ca1ba2a 100644
--- a/src/cache.ts
+++ b/src/cache.ts
@@ -5,7 +5,7 @@ export function stringifyCache(cache: Sponsorship[]): string {
   return JSON.stringify(
     cache,
     (_key, value) => {
-      if (value && value.type === 'Buffer' && Array.isArray(value.data)) {
+      if (value?.type === 'Buffer' && Array.isArray(value.data)) {
         return Buffer.from(value.data).toString('base64')
       }
       return value
diff --git a/src/cli.ts b/src/cli.ts
index bb38559..d523af7 100644
--- a/src/cli.ts
+++ b/src/cli.ts
@@ -3,7 +3,7 @@ import cac from 'cac'
 import { version } from '../package.json'
 import { run } from './run'
 
-const RE_FILTER = /([<>=]+)(\d+)/
+const RE_FILTER = /^(<=?|>=?)(\d+)$/
 const cli = cac('contributors-svg')
   .version(version)
   .help()
@@ -37,7 +37,11 @@ cli.parse()
  * @param template
  */
 function createFilterFromString(template: string): ContribkitConfig['filter'] {
-  const [_, op, value] = template.split(RE_FILTER)
+  const match = RE_FILTER.exec(template)
+  if (!match)
+    throw new Error(`Unable to parse filter template ${template}`)
+
+  const [, op, value] = match
   const num = Number.parseInt(value)
   if (op === '<')
     return s => s.monthlyDollars < num
diff --git a/src/configs/index.ts b/src/configs/index.ts
index d7d5250..a680997 100644
--- a/src/configs/index.ts
+++ b/src/configs/index.ts
@@ -69,13 +69,13 @@ export async function loadConfig(inlineConfig: ContribkitConfig = {}): Promise<R
   if (!['sponsors', 'sponsees'].includes(resolved.mode))
     throw new Error(`Invalid mode: ${resolved.mode}. Expected "sponsors" or "sponsees".`)
 
-  resolved.name = inlineConfig.name || config.name || envConfig.name || resolved.mode
+  resolved.name = inlineConfig.name ?? config.name ?? envConfig.name ?? resolved.mode
 
   return resolved
 }
 
 export function partitionTiers(sponsors: Sponsorship[], tiers: Tier[], includePastSponsors?: boolean): TierPartition[] {
-  const tierMappings = tiers!.map<TierPartition>(tier => ({
+  const tierMappings = tiers.map<TierPartition>(tier => ({
     monthlyDollars: tier.monthlyDollars ?? 0,
     tier,
     sponsors: [],
@@ -88,8 +88,9 @@ export function partitionTiers(sponsors: Sponsorship[], tiers: Tier[], includePa
   if (finalSponsors.length !== 1)
     throw new Error(`There should be exactly one tier with no \`monthlyDollars\`, but got ${finalSponsors.length}`)
 
+  sponsors.sort((a, b) => Date.parse(a.createdAt!) - Date.parse(b.createdAt!))
+
   sponsors
-    .sort((a, b) => Date.parse(a.createdAt!) - Date.parse(b.createdAt!))
     .filter(s => s.monthlyDollars > 0 || includePastSponsors) // Past sponsors monthlyDollars is -1
     .forEach((sponsor) => {
       const tier = tierMappings.find(t => sponsor.monthlyDollars >= t.monthlyDollars) ?? tierMappings[0]
diff --git a/src/processing/image.ts b/src/processing/image.ts
index d29a58a..187f689 100644
--- a/src/processing/image.ts
+++ b/src/processing/image.ts
@@ -51,7 +51,7 @@ export async function resolveAvatars(
     if (pngBuffer) {
       // Store the highest resolution version we use of the original image
       // Stored in webp to save space
-      ship.sponsor.avatarBuffer = await resizeImage(pngBuffer, 120, 'webp')
+      ship.sponsor.avatarBuffer = await resizeImage(pngBuffer, 'webp', 120)
     }
   })))
 }
@@ -59,8 +59,8 @@ export async function resolveAvatars(
 const cache = new Map<Buffer, Map<string, Buffer>>()
 export async function resizeImage(
   image: Buffer,
-  size = 100,
   format: ImageFormat,
+  size = 100,
 ) {
   const cacheKey = `${size}:${format}`
   if (cache.has(image)) {
diff --git a/src/processing/svg.ts b/src/processing/svg.ts
index 94a297c..bda2196 100644
--- a/src/processing/svg.ts
+++ b/src/processing/svg.ts
@@ -42,13 +42,13 @@ export async function generateBadge(
   const { size } = preset.avatar
   let avatar = sponsor.avatarBuffer!
   if (size < 50) {
-    avatar = await resizeImage(avatar, 50, imageFormat)
+    avatar = await resizeImage(avatar, imageFormat, 50)
   }
   else if (size < 80) {
-    avatar = await resizeImage(avatar, 80, imageFormat)
+    avatar = await resizeImage(avatar, imageFormat, 80)
   }
   else if (imageFormat === 'png') {
-    avatar = await resizeImage(avatar, 120, imageFormat)
+    avatar = await resizeImage(avatar, imageFormat, 120)
   }
 
   const avatarBase64 = avatar.toString('base64')
@@ -122,5 +122,5 @@ ${this.body}
 }
 
 function encodeHtmlEntities(str: string) {
-  return String(str).replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;')
+  return String(str).replaceAll('&', '&amp;').replaceAll('<', '&lt;').replaceAll('>', '&gt;').replaceAll('"', '&quot;')
 }
diff --git a/src/providers/afdian.ts b/src/providers/afdian.ts
index 3dc915e..9c339bc 100644
--- a/src/providers/afdian.ts
+++ b/src/providers/afdian.ts
@@ -109,5 +109,7 @@ export async function fetchAfdianSponsors(options: ContribkitConfig['afdian'] =
 }
 
 function md5(token: string, params: string, ts: number, userId: string) {
-  return createHash('md5').update(`${token}params${params}ts${ts}user_id${userId}`).digest('hex')
+  return createHash('md5') // NOSONAR(typescript:S4790): Afdian requires MD5 request signatures.
+    .update(`${token}params${params}ts${ts}user_id${userId}`)
+    .digest('hex')
 }
diff --git a/src/providers/githubContributors.ts b/src/providers/githubContributors.ts
index 5ee56a3..a690f7c 100644
--- a/src/providers/githubContributors.ts
+++ b/src/providers/githubContributors.ts
@@ -58,7 +58,7 @@ export async function fetchGitHubContributors(
       },
     )
 
-    if (!response || !response.length)
+    if (!response?.length)
       break
 
     allContributors.push(...response)
diff --git a/src/providers/gitlabContributors.ts b/src/providers/gitlabContributors.ts
index 92cf637..515e7a4 100644
--- a/src/providers/gitlabContributors.ts
+++ b/src/providers/gitlabContributors.ts
@@ -61,7 +61,7 @@ export async function fetchGitlabContributors(
       },
     )
 
-    if (!response || !response.length)
+    if (!response?.length)
       break
 
     allContributors.push(...response)
diff --git a/src/providers/index.ts b/src/providers/index.ts
index db10d17..9ef5765 100644
--- a/src/providers/index.ts
+++ b/src/providers/index.ts
@@ -29,7 +29,7 @@ export const ProvidersMap = {
 export function guessProviders(config: ContribkitConfig) {
   const items: ProviderName[] = []
   const credentials = getCredentials(config)
-  if (config.github && config.github.login)
+  if (config.github?.login)
     items.push('github')
 
   if (credentials.patreon?.token)
@@ -44,7 +44,7 @@ export function guessProviders(config: ContribkitConfig) {
   if (credentials.polar?.token)
     items.push('polar')
 
-  if (config.liberapay && config.liberapay.login)
+  if (config.liberapay?.login)
     items.push('liberapay')
 
   if (config.githubContributors?.login && credentials.githubContributors?.token)
diff --git a/src/providers/opencollective.ts b/src/providers/opencollective.ts
index 10a2f93..04b296d 100644
--- a/src/providers/opencollective.ts
+++ b/src/providers/opencollective.ts
@@ -70,13 +70,12 @@ export async function fetchOpenCollectiveSponsors(
 
       sponsors.push(...(nodes || []))
 
-      if ((nodes.length) !== 0) {
-        if (totalCount > offset + nodes.length)
-          offset += nodes.length
-        else
-          offset = undefined
-      }
-      else { offset = undefined }
+      if (nodes.length === 0)
+        offset = undefined
+      else if (totalCount > offset + nodes.length)
+        offset += nodes.length
+      else
+        offset = undefined
     } while (offset)
   }
 
@@ -99,13 +98,12 @@ export async function fetchOpenCollectiveSponsors(
     const totalCount = data.data.account.transactions.totalCount
 
     monthlyTransactions.push(...(nodes || []))
-    if ((nodes.length) !== 0) {
-      if (totalCount > offset + nodes.length)
-        offset += nodes.length
-      else
-        offset = undefined
-    }
-    else { offset = undefined }
+    if (nodes.length === 0)
+      offset = undefined
+    else if (totalCount > offset + nodes.length)
+      offset += nodes.length
+    else
+      offset = undefined
   } while (offset)
 
   const sponsorships: [string, Sponsorship][] = sponsors
@@ -139,12 +137,12 @@ export async function fetchOpenCollectiveSponsors(
   const transactionsBySponsorId: Map<string, Sponsorship> = monthlySponsorships.reduce((map, [id, sponsor]) => {
     const existingSponsor = map.get(id)
     if (existingSponsor) {
-      const createdAt = new Date(sponsor.createdAt!)
-      const existingSponsorCreatedAt = new Date(existingSponsor.createdAt!)
+      const createdAt = toDate(sponsor.createdAt)
+      const existingSponsorCreatedAt = toDate(existingSponsor.createdAt)
       if (createdAt >= existingSponsorCreatedAt)
         map.set(id, sponsor)
 
-      else if (new Date(existingSponsorCreatedAt.getFullYear(), existingSponsorCreatedAt.getMonth(), 1) === new Date(createdAt.getFullYear(), createdAt.getMonth(), 1))
+      else if (isSameMonth(existingSponsorCreatedAt, createdAt))
         existingSponsor.monthlyDollars += sponsor.monthlyDollars
     }
     else { map.set(id, sponsor) }
@@ -156,8 +154,8 @@ export async function fetchOpenCollectiveSponsors(
     .reduce((map, [id, sponsor]) => {
       const existingSponsor = map.get(id)
       if (existingSponsor) {
-        const createdAt = new Date(sponsor.createdAt!)
-        const existingSponsorCreatedAt = new Date(existingSponsor.createdAt!)
+        const createdAt = toDate(sponsor.createdAt)
+        const existingSponsorCreatedAt = toDate(existingSponsor.createdAt)
         if (createdAt >= existingSponsorCreatedAt)
           map.set(id, sponsor)
       }
@@ -195,7 +193,7 @@ function createSponsorFromOrder(order: any): [string, Sponsorship] | undefined {
       avatarUrl: order.fromAccount.imageUrl,
       websiteUrl: normalizeUrl(getBestUrl(order.fromAccount.socialLinks)),
       linkUrl: `https://opencollective.com/${slug}`,
-      socialLogins: getSocialLogins(order.fromAccount.socialLinks, slug),
+      socialLogins: getSocialLogins(slug, order.fromAccount.socialLinks),
     },
     isOneTime: order.frequency === 'ONETIME',
     monthlyDollars,
@@ -242,14 +240,14 @@ function createSponsorFromTransaction(transaction: any, excludeOrders: string[],
       type: getAccountType(account.type),
       login: slug,
       avatarUrl: account.imageUrl,
-      websiteUrl: normalizeUrl(getBestUrl(account.socialLinks || [])),
+      websiteUrl: normalizeUrl(getBestUrl(account.socialLinks ?? [])),
       linkUrl: `https://opencollective.com/${slug}`,
-      socialLogins: getSocialLogins(account.socialLinks || [], slug),
+      socialLogins: getSocialLogins(slug, account.socialLinks),
     },
     isOneTime: transaction.order?.frequency === 'ONETIME',
     monthlyDollars,
     privacyLevel: sponseesMode ? 'PUBLIC' : (account.isIncognito ? 'PRIVATE' : 'PUBLIC'),
-    tierName: transaction.order?.tier?.name || transaction.tier?.name,
+    tierName: transaction.order?.tier?.name ?? transaction.tier?.name,
     createdAt: sponseesMode
       ? transaction.createdAt
       : transaction.order?.frequency === 'ONETIME'
@@ -432,13 +430,21 @@ function getBestUrl(socialLinks: SocialLink[]): string | undefined {
   return urls[0]
 }
 
+function isSameMonth(a: Date, b: Date) {
+  return a.getFullYear() === b.getFullYear() && a.getMonth() === b.getMonth()
+}
+
+function toDate(value: string | undefined) {
+  return new Date(value ?? Number.NaN)
+}
+
 const RE_GITHUB_URL = /github\.com\/([^/]*)/
 
-function getSocialLogins(socialLinks: SocialLink[] = [], opencollectiveLogin: string): Record<string, string> {
+function getSocialLogins(opencollectiveLogin: string, socialLinks: SocialLink[] = []): Record<string, string> {
   const socialLogins: Record<string, string> = {}
   for (const link of socialLinks) {
     if (link.type === 'GITHUB') {
-      const login = link.url.match(RE_GITHUB_URL)?.[1]
+      const login = RE_GITHUB_URL.exec(link.url)?.[1]
       if (login)
         socialLogins.github = login
     }
diff --git a/src/renders/circles.ts b/src/renders/circles.ts
index aac2a8f..be9c9f8 100644
--- a/src/renders/circles.ts
+++ b/src/renders/circles.ts
@@ -1,6 +1,11 @@
 import type { ContribkitRenderer, Sponsorship } from '../types'
 import { generateBadge, SvgComposer } from '../processing/svg'
 
+interface SponsorHierarchy extends Sponsorship {
+  children?: Sponsorship[]
+  id?: string
+}
+
 export const circlesRenderer: ContribkitRenderer = {
   name: 'contribkit:circles',
   async renderSVG(config, sponsors) {
@@ -18,20 +23,21 @@ export const circlesRenderer: ContribkitRenderer = {
     function defaultInterop(sponsor: Sponsorship) {
       return sponsor.monthlyDollars < 0
         ? radiusPast
-        : lerp(radiusMin, radiusMax, (Math.max(0.1, sponsor.monthlyDollars || 0) / amountMax) ** 0.9)
+        : lerp(radiusMin, radiusMax, (Math.max(0.1, sponsor.monthlyDollars ?? 0) / amountMax) ** 0.9)
     }
 
     if (!config.includePastSponsors)
       sponsors = sponsors.filter(sponsor => sponsor.monthlyDollars > 0)
 
-    const root = hierarchy({ ...sponsors[0], children: sponsors, id: 'root' })
+    const rootData: SponsorHierarchy = { ...sponsors[0], children: sponsors, id: 'root' }
+    const root = hierarchy(rootData)
       .sum(d => weightInterop(d, amountMax))
-      .sort((a, b) => (b.value || 0) - (a.value || 0))
+      .sort((a, b) => (b.value ?? 0) - (a.value ?? 0))
 
-    const p = pack<typeof sponsors[0]>()
+    const p = pack<SponsorHierarchy>()
     p.size([config.width, config.width])
     p.padding(config.width / 400)
-    const circles = p(root as any).descendants().slice(1)
+    const circles = p(root).descendants().slice(1)
 
     for (const circle of circles) {
       composer.addRaw(await generateBadge(
diff --git a/src/run.ts b/src/run.ts
index 41f8e48..6f71ba5 100644
--- a/src/run.ts
+++ b/src/run.ts
@@ -41,7 +41,7 @@ export async function run(inlineConfig?: ContribkitConfig, t = consola) {
       : config.cacheFile,
   )
 
-  const providers = resolveProviders(config.providers || guessProviders(config))
+  const providers = resolveProviders(config.providers ?? guessProviders(config))
 
   if (config.renders?.length) {
     const names = new Set<string>()
@@ -63,60 +63,24 @@ export async function run(inlineConfig?: ContribkitConfig, t = consola) {
       t.info(`Fetching sponsorships from ${i.name}...`)
       let sponsors = await i.fetchSponsors(config)
       sponsors.forEach(s => s.provider = i.name)
-      sponsors = await config.onSponsorsFetched?.(sponsors, i.name) || sponsors
+      sponsors = (await config.onSponsorsFetched?.(sponsors, i.name)) ?? sponsors
       t.success(`${sponsors.length} sponsorships fetched from ${i.name}`)
       allSponsors.push(...sponsors)
     }
 
     // Custom hook
-    allSponsors = await config.onSponsorsAllFetched?.(allSponsors) || allSponsors
+    allSponsors = (await config.onSponsorsAllFetched?.(allSponsors)) ?? allSponsors
 
     // Merge sponsors
     {
       const sponsorsMergeMap = new Map<Sponsorship, Set<Sponsorship>>()
 
-      function pushGroup(group: Sponsorship[]) {
-        const existingSets = new Set(group.map(s => sponsorsMergeMap.get(s)).filter(notNullish))
-        let set: Set<Sponsorship>
-        if (existingSets.size === 1) {
-          set = [...existingSets.values()][0]
-        }
-        else if (existingSets.size === 0) {
-          set = new Set(group)
-        }
-        // Multiple sets, merge them into one
-        else {
-          set = new Set()
-          for (const s of existingSets) {
-            for (const i of s)
-              set.add(i)
-          }
-        }
-
-        for (const s of group) {
-          set.add(s)
-          sponsorsMergeMap.set(s, set)
-        }
-      }
-
-      function matchSponsor(sponsor: Sponsorship, matcher: SponsorMatcher) {
-        if (matcher.provider && sponsor.provider !== matcher.provider)
-          return false
-        if (matcher.login && sponsor.sponsor.login !== matcher.login)
-          return false
-        if (matcher.name && sponsor.sponsor.name !== matcher.name)
-          return false
-        if (matcher.type && sponsor.sponsor.type !== matcher.type)
-          return false
-        return true
-      }
-
       for (const rule of config.mergeSponsors || []) {
         if (typeof rule === 'function') {
           for (const ship of allSponsors) {
             const result = rule(ship, allSponsors)
             if (result)
-              pushGroup(result)
+              pushSponsorGroup(sponsorsMergeMap, result)
           }
         }
         else {
@@ -126,7 +90,7 @@ export async function run(inlineConfig?: ContribkitConfig, t = consola) {
               t.warn(`No sponsor matched for ${JSON.stringify(matcher)}`)
             return matched
           })
-          pushGroup(group)
+          pushSponsorGroup(sponsorsMergeMap, group)
         }
       }
 
@@ -137,23 +101,11 @@ export async function run(inlineConfig?: ContribkitConfig, t = consola) {
           for (const [provider, login] of Object.entries(ship.sponsor.socialLogins)) {
             const matched = allSponsors.filter(s => s.sponsor.login === login && s.provider === provider)
             if (matched)
-              pushGroup([ship, ...matched])
+              pushSponsorGroup(sponsorsMergeMap, [ship, ...matched])
           }
         }
       }
 
-      function mergeSponsors(main: Sponsorship, sponsors: Sponsorship[]) {
-        const all = [main, ...sponsors]
-        main.isOneTime = all.every(s => s.isOneTime)
-        main.expireAt = all.map(s => s.expireAt).filter(notNullish).sort((a, b) => b.localeCompare(a))[0]
-        main.createdAt = all.map(s => s.createdAt).filter(notNullish).sort((a, b) => a.localeCompare(b))[0]
-        main.monthlyDollars = all.every(s => s.monthlyDollars === -1)
-          ? -1
-          : all.filter(s => s.monthlyDollars > 0).reduce((a, b) => a + b.monthlyDollars, 0)
-        main.provider = [...new Set(all.map(s => s.provider))].join('+')
-        return main
-      }
-
       const removeSponsors = new Set<Sponsorship>()
       const groups = new Set(sponsorsMergeMap.values())
       for (const group of groups) {
@@ -218,10 +170,10 @@ export async function run(inlineConfig?: ContribkitConfig, t = consola) {
   allSponsors.sort((a, b) =>
     b.monthlyDollars - a.monthlyDollars // DESC amount
     || Date.parse(b.createdAt!) - Date.parse(a.createdAt!) // DESC date
-    || (b.sponsor.login || b.sponsor.name).localeCompare(a.sponsor.login || a.sponsor.name), // ASC name
+    || (b.sponsor.login ?? b.sponsor.name).localeCompare(a.sponsor.login ?? a.sponsor.name), // ASC name
   )
 
-  allSponsors = await config.onSponsorsReady?.(allSponsors) || allSponsors
+  allSponsors = (await config.onSponsorsReady?.(allSponsors)) ?? allSponsors
 
   if (config.renders?.length) {
     t.info(`Generating with ${config.renders.length} renders...`)
@@ -230,7 +182,7 @@ export async function run(inlineConfig?: ContribkitConfig, t = consola) {
         ...fullConfig,
         ...renderOptions,
       }
-      const renderer = builtinRenderers[mergedOptions.renderer || 'tiers']
+      const renderer = builtinRenderers[mergedOptions.renderer ?? 'tiers']
       await applyRenderer(
         renderer,
         config,
@@ -241,7 +193,7 @@ export async function run(inlineConfig?: ContribkitConfig, t = consola) {
     }))
   }
   else {
-    const renderer = builtinRenderers[fullConfig.renderer || 'tiers']
+    const renderer = builtinRenderers[fullConfig.renderer ?? 'tiers']
     await applyRenderer(
       renderer,
       config,
@@ -260,7 +212,7 @@ export async function applyRenderer(
   t = consola,
 ) {
   sponsors = [...sponsors]
-  sponsors = await renderOptions.onBeforeRenderer?.(sponsors) || sponsors
+  sponsors = (await renderOptions.onBeforeRenderer?.(sponsors)) ?? sponsors
 
   const logPrefix = c.dim`[${renderOptions.name}]`
   const dir = resolve(process.cwd(), config.outputDir)
@@ -271,14 +223,13 @@ export async function applyRenderer(
   if (!renderOptions.includePrivate)
     sponsors = sponsors.filter(s => s.privacyLevel !== 'PRIVATE')
 
-  if (!renderOptions.imageFormat)
-    renderOptions.imageFormat = 'webp'
+  renderOptions.imageFormat ??= 'webp'
 
   const processingSvg = (async () => {
     let svgWebp = await renderer.renderSVG(renderOptions, sponsors)
 
     if (renderOptions.onSvgGenerated) {
-      svgWebp = await renderOptions.onSvgGenerated(svgWebp) || svgWebp
+      svgWebp = (await renderOptions.onSvgGenerated(svgWebp)) ?? svgWebp
     }
     return svgWebp
   })()
@@ -286,59 +237,95 @@ export async function applyRenderer(
   if (renderOptions.formats) {
     let svgPng: Promise<string> | undefined
 
-    await Promise.all([
-      renderOptions.formats.map(async (format) => {
-        if (!outputFormats.includes(format))
-          throw new Error(`Unsupported format: ${format}`)
+    await Promise.all(renderOptions.formats.map(async (format) => {
+      if (!outputFormats.includes(format))
+        throw new Error(`Unsupported format: ${format}`)
 
-        const path = join(dir, `${renderOptions.name}.${format}`)
+      const path = join(dir, `${renderOptions.name}.${format}`)
 
-        let data: string | Buffer
+      let data: string | Buffer
 
-        if (format === 'svg') {
-          t.info(`${logPrefix} Composing SVG...`)
-          data = await processingSvg
-        }
+      if (format === 'svg') {
+        t.info(`${logPrefix} Composing SVG...`)
+        data = await processingSvg
+      }
+      else if (format === 'json') {
+        data = JSON.stringify(sponsors, null, 2)
+      }
+      else {
+        svgPng ??= renderer.renderSVG({
+          ...renderOptions,
+          imageFormat: 'png',
+        }, sponsors)
+
+        const pngSvg = await svgPng
+        data = format === 'png'
+          ? await svgToPng(pngSvg)
+          : await svgToWebp(pngSvg)
+      }
 
-        if (format === 'json') {
-          data = JSON.stringify(sponsors, null, 2)
-        }
+      await fsp.writeFile(path, data)
 
-        if (format === 'png' || format === 'webp') {
-          if (!svgPng) {
-            // Sharp can't render embedded Webp so re-generate with png
-            // https://github.com/lovell/sharp/issues/4254
-            svgPng = renderer.renderSVG({
-              ...renderOptions,
-              imageFormat: 'png',
-            }, sponsors)
-          }
+      t.success(`${logPrefix} Wrote to ${r(path)}`)
+    }))
+  }
+}
 
-          if (format === 'png') {
-            data = await svgToPng(await svgPng)
-          }
+function pushSponsorGroup(sponsorsMergeMap: Map<Sponsorship, Set<Sponsorship>>, group: Sponsorship[]) {
+  const existingSets = new Set(group.map(s => sponsorsMergeMap.get(s)).filter(notNullish))
+  let set = existingSets.values().next().value
+  if (!set) {
+    set = new Set(group)
+  }
+  // Multiple sets, merge them into one
+  else if (existingSets.size > 1) {
+    set = new Set()
+    for (const existingSet of existingSets) {
+      for (const sponsor of existingSet)
+        set.add(sponsor)
+    }
+  }
 
-          if (format === 'webp') {
-            data = await svgToWebp(await svgPng)
-          }
-        }
+  for (const sponsor of group) {
+    set.add(sponsor)
+    sponsorsMergeMap.set(sponsor, set)
+  }
+}
 
-        await fsp.writeFile(path, data!)
+function matchSponsor(sponsor: Sponsorship, matcher: SponsorMatcher) {
+  if (matcher.provider && sponsor.provider !== matcher.provider)
+    return false
+  if (matcher.login && sponsor.sponsor.login !== matcher.login)
+    return false
+  if (matcher.name && sponsor.sponsor.name !== matcher.name)
+    return false
+  if (matcher.type && sponsor.sponsor.type !== matcher.type)
+    return false
+  return true
+}
 
-        t.success(`${logPrefix} Wrote to ${r(path)}`)
-      }),
-    ])
-  }
+function mergeSponsors(main: Sponsorship, sponsors: Sponsorship[]) {
+  const all = [main, ...sponsors]
+  main.isOneTime = all.every(s => s.isOneTime)
+  main.expireAt = all.map(s => s.expireAt).filter(notNullish).sort((a, b) => b.localeCompare(a))[0]
+  main.createdAt = all.map(s => s.createdAt).filter(notNullish).sort((a, b) => a.localeCompare(b))[0]
+  main.monthlyDollars = all.every(s => s.monthlyDollars === -1)
+    ? -1
+    : all.filter(s => s.monthlyDollars > 0).reduce((a, b) => a + b.monthlyDollars, 0)
+  main.provider = [...new Set(all.map(s => s.provider))].join('+')
+  return main
 }
 
+type Replacement = ((sponsor: Sponsorship) => string) | [string, string]
+
 function normalizeReplacements(replaces: ContribkitMainConfig['replaceLinks']) {
   const array = (Array.isArray(replaces) ? replaces : [replaces]).filter(notNullish)
-  const entries = array.map((i) => {
-    if (!i)
-      return []
-    if (typeof i === 'function')
-      return [i]
-    return Object.entries(i) as [string, string][]
-  }).flat()
+  const entries: Replacement[] = []
+  for (const item of array) {
+    if (typeof item === 'function')
+      entries.push(item)
+    else
+      entries.push(...Object.entries(item) as [string, string][])
+  }
   return entries
 }
diff --git a/src/types.ts b/src/types.ts
index a85df63..cafd88f 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -64,7 +64,7 @@ export interface Sponsorship {
   createdAt?: string
   expireAt?: string
   isOneTime?: boolean
-  provider?: ProviderName | string
+  provider?: string
   /**
    * Raw data from provider
    */
@@ -76,6 +76,7 @@ export const outputFormats = ['svg', 'png', 'webp', 'json'] as const
 export type OutputFormat = typeof outputFormats[number]
 
 export type ProviderName = 'github' | 'patreon' | 'opencollective' | 'afdian' | 'polar' | 'liberapay' | 'githubContributors' | 'gitlabContributors' | 'crowdinContributors' | 'githubContributions'
+export type HookResult<T> = PromiseLike<T | void | undefined | null> | T | void | undefined | null
 
 export type GitHubAccountType = 'user' | 'organization'
 export type SponsorshipMode = 'sponsors' | 'sponsees'
@@ -340,12 +341,12 @@ export interface ContribkitRenderOptions {
   /**
    * Hook to modify sponsors data before rendering.
    */
-  onBeforeRenderer?: (sponsors: Sponsorship[]) => PromiseLike<void | Sponsorship[]> | void | Sponsorship[]
+  onBeforeRenderer?: (sponsors: Sponsorship[]) => HookResult<Sponsorship[]>
 
   /**
    * Hook to get or modify the SVG before writing.
    */
-  onSvgGenerated?: (svg: string) => PromiseLike<string | void | undefined | null> | string | void | undefined | null
+  onSvgGenerated?: (svg: string) => HookResult<string>
 }
 
 export interface ContribkitConfig extends ProvidersConfig, ContribkitRenderOptions {
@@ -427,17 +428,17 @@ export interface ContribkitConfig extends ProvidersConfig, ContribkitRenderOptio
   /**
    * Hook to modify sponsors data for each provider.
    */
-  onSponsorsFetched?: (sponsors: Sponsorship[], provider: ProviderName | string) => PromiseLike<void | Sponsorship[]> | void | Sponsorship[]
+  onSponsorsFetched?: (sponsors: Sponsorship[], provider: string) => HookResult<Sponsorship[]>
 
   /**
    * Hook to modify merged sponsors data before fetching the avatars.
    */
-  onSponsorsAllFetched?: (sponsors: Sponsorship[]) => PromiseLike<void | Sponsorship[]> | void | Sponsorship[]
+  onSponsorsAllFetched?: (sponsors: Sponsorship[]) => HookResult<Sponsorship[]>
 
   /**
    * Hook to modify sponsors data before rendering.
    */
-  onSponsorsReady?: (sponsors: Sponsorship[]) => PromiseLike<void | Sponsorship[]> | void | Sponsorship[]
+  onSponsorsReady?: (sponsors: Sponsorship[]) => HookResult<Sponsorship[]>
 
   /**
    * Url to fallback avatar.
@@ -457,7 +458,7 @@ export interface ContribkitConfig extends ProvidersConfig, ContribkitRenderOptio
 }
 
 export interface SponsorMatcher extends Partial<Pick<Sponsor, 'login' | 'name' | 'type'>> {
-  provider?: ProviderName | string
+  provider?: string
 }
 
 export type ContribkitMainConfig = Omit<ContribkitConfig, keyof ContribkitRenderOptions>