Features

Built with a cappella singing in mind.

Most worship-presentation software is built for the praise-band model — and a cappella congregations make do. AssemblyFlow flips that. Shape-note SATB hymnal projection, song leader mode with a built-in pitch generator, multi-hymnal cross-references — plus a livestream stack that's a first-class citizen, not an afterthought.

What sets it apart

Three things AssemblyFlow does that nothing else does well.

Built with a cappella singing in mind.

Shape-note SATB hymnal projection. Hymnal page references across Songs of Faith and Praise, Sacred Selections, Christian Hymnal, and Praise for the Lord. Song leader mode with a starting-pitch tone generator. Lord's Supper and communion templates. A Gospel Meeting series planner with printable flyers.

Livestream-first, not an afterthought.

An HTTP server you point OBS at as a Browser Source — your YouTube and Zoom viewers see the same slides as the in-room audience, rendered live at any resolution. Plus NDI broadcast for vMix and Wirecast. Plus a virtual webcam for direct Zoom and Teams.

Honor-system licensing.

Free forever for congregations of 50 or fewer — no nag, no watermark, no time bomb. Honest tier-based pricing for larger churches that scales by scope of use, not head count. And we will never block projection mid-service, even if a billing card fails.

Song leader mode

Everything an a cappella song leader needs, in one panel.

For congregations with a song leader instead of a band. A starting-pitch tone generator pipes a sine wave through the computer speakers — no pitch pipe required. Singing key, tempo BPM, hymnal page references, and leader notes ("men only on chorus," "v3 a cappella echo") are stored per song and shown on the stage display where only the leader can see them.

  • Pitch generator — sine-wave starting note through computer speakers
  • Hymnal cross-references — Songs of Faith and Praise, Sacred Selections, Christian Hymnal, Praise for the Lord
  • Singing key per song; per-service override when the regular leader is out
  • Tempo BPM and leader notes per song
  • Verse selection — pick "1, 2, 4" and Next auto-skips unselected verses
Song · 3 of 11
A Mighty Fortress
Key · D
Tempo · 88 BPM
D4
293.66 Hz · sine · 0.8 s
SOFP 59 SS 121 CH 47 PFL 38
Singing 1, 2, 4 · v.3 skipped
1 — A Mighty Fortress
△◯△◯ △◯△◯ △◯◯△ △◯△◯ ◯△◯△ ◯△◯△ ◯△△◯ ◯△◯△ △△◯◯ △△◯◯ △△◯◯ △△◯◯ ◯◯△△ ◯◯△△ ◯◯△△ ◯◯△△
A might-y for-tress is our God,
A bul-wark nev-er fail-ing.
Words and music: Martin Luther
Song library

85 shape-note hymns. Or any song, any format, your way.

The 85-hymn library ships pre-rendered as SATB shape-note slides from The Paperless Hymnal — drop one onto the order and it projects without setup. Every song can also be displayed as live-styled lyric text instead, so the same hymn projects as sheet music on Sunday morning and as plain words on Wednesday night.

Bring your own songs by typing them, pasting them, or bulk-dropping a folder of ChordPro, OnSong, and plain-text files.

Display mode per song

Auto · Image · Lyrics. The same hymn can project as SATB sheet music or as live-styled lyric text — toggle per service.

Custom song editor

Type or paste lyrics. Auto-detects "Verse 1," "Chorus," "Bridge," "Refrain" headers; falls back to blank-line splitting.

Bulk import

Drop .txt, .cho, .chopro, .crd, .pro, .onsong, .md. ChordPro directives auto-extracted; chord markers stripped.

PowerPoint drag-and-drop

Drop a .pptx onto the window; each slide becomes a projection slide — sermon decks, special-music slides, anything.

Bilingual lyrics

Parallel translation side-by-side — English + Spanish, English + Korean, or any pair.

Chord charts (stage-only)

ChordPro / OnSong text stored per song, rendered on the stage display where the band sees it — never on the audience screen.

Chord transposition

Shift chords up or down without changing the stored file. Per-service override for visiting singers.

Audio backing tracks

MP3 or WAV per song. Play / Pause / Stop controls during projection.

Full-text search & tags

Search title, lyrics, authors, copyright, publisher. Filter by tag — "Christmas," "Communion," "Invitation."

Video and image slides

Video and image slides.

Drop in any video or image. Announcements, special music, sermon illustrations.

Two new service-item types in v1.3 round out what a service plan can hold. Drop an MP4, MOV, WebM, or MKV file — or paste a YouTube URL and AssemblyFlow downloads it locally for offline playback. Drop a PNG, JPG, WebP, BMP, or GIF — Canva announcement graphics, family photos for memorial services, sermon illustrations.

  • Video — local file or YouTube URL. Auto-download via yt-dlp. Operator pause / resume / restart controls during playback.
  • Image — drag-and-drop or file picker. Full-screen projection. Ideal for announcement slides designed in Canva.
  • Honors the standard service flow — preview pane, Go Live, projection + livestream + virtual webcam all show them.
Farewell, Rob!
Fellowship hall · after morning assembly
Image slide 1920 × 1080
Sunday Morning · May 31, 2026
Preacher: Tim Brown · Planned: 1h 12m
  1. Pre-service countdown 5:00
  2. Welcome & announcements 2:30
  3. A Mighty Fortress — v.1, 2, 4 4:10
  4. Romans 8:28–30 (KJV) 1:20
  5. Lord's Supper 8:00
  6. Sermon — Predestined 38:00
Service planning

Templates for the way real services run.

Drag-and-drop service order, autosave every change, undo back twenty steps. Templates for Sunday Morning, Wednesday Night, Bible Class, and Gospel Meeting are built in — clone one and customize it for next week. The vocabulary follows your tradition ("assembly" vs "service," "preacher" vs "pastor") via a toggle.

  • Lord's Supper template — pre-built with scripture readings, suggested hymns, prayer prompts
  • Baptism quick-launch — water-drop icon in the toolbar projects baptism scripture on demand
  • Gospel Meeting series planner — plan a multi-night series once, generate per-night templates, export a printable promotional flyer PDF
  • Quick navigator (Ctrl+K) — fuzzy-find any item, song, or scripture
  • Service duration tracking — planned vs actual elapsed
  • PDF export of the service order for the preacher / AV tech; email summary to the team
Scripture

The BSV — built in, defaulted on, no extra setup.

Other worship-presentation software treats Bible translations as plumbing — you pick from a generic list and they all look the same. AssemblyFlow defaults to the Biblical Standard Version, Straight Truth Press's own faithful, readable translation, available free with every install. KJV, ASV, ESV, and api.bible's catalog are all built in — but the BSV is the one you'll find waiting when you open AssemblyFlow for the first time.

Type John 3:16 or Romans 8:28-30 and hit Enter. AssemblyFlow validates the reference against the active translation, then splits each verse onto its own slide with the reference as the heading.

  • BSVBiblical Standard Version. Default, bundled, offline, free. Translated & published by Straight Truth Press.
  • KJV & ASV bundled offline — never need internet for these
  • ESV via the free api.esv.org key — 5,000 verses/day, non-commercial
  • api.bible Starter — any 3 copyrighted Bibles (NIV, NASB, CSB, NLT, NKJV, The Message), plus a deep Creative Commons / Public Domain library including non-English languages. Free key, 5,000 calls/month.
  • Bilingual scripture — English + Spanish, English + Korean, or any pair side-by-side
  • Verse / phrase highlighter — paste a phrase mid-service; matching text gets yellow underline emphasis on every output (projection, livestream, stage display) at once
  • All API responses cached to disk — re-using the same verse is instant and works offline next time
Romans 8:28-30
BSV KJV ASV ESV NIV + es
ROMANS 8:28 · BSV
And we know that for those who love God all things work together for good, for those who are called according to his purpose.
ROMANS 8:29 · BSV
For those whom he foreknew he also predestined to be conformed to the image of his Son…
Livestream integration

The reason most churches buy AssemblyFlow.

Other tools treat livestream as a "second screen" exported as a video signal. AssemblyFlow exposes your slides as an HTTP endpoint OBS can subscribe to directly — your YouTube and Zoom viewers see crisp, scaled, real-time slides at whatever resolution the platform wants.

OBS Browser Source · the headline feature

Point OBS at one URL. Your livestream sees the slides.

AssemblyFlow exposes an HTTP endpoint at http://<lan-ip>:<port>/obs. Add it to OBS as a Browser Source and your livestream is now showing real-time projection slides. Query params let you target every platform's preferred resolution — fonts and padding scale automatically.

  • /obs?resolution=1920x1080 — YouTube
  • /obs?resolution=1280x720 — Facebook
  • /obs?resolution=854x480 — low-bandwidth fallback
  • Fonts and padding auto-scale for legibility at every size
  • Live updates — operator clicks Next, the stream updates in <1 frame
OBS Studio · Browser Source · http://192.168.1.42:8788/obs?resolution=1920x1080
● ON AIR
A might-y for-tress is our God,
A bul-wark nev-er fail-ing.
1920×1080 · 30fps live · 4.2 Mbps · 0 dropped
Auto-setup OBS scenes · new in v1.3

One button builds your three OBS scenes for you.

Open the OBS Studio integration dialog, click Test connection, and once it succeeds a single Auto-setup scenes button creates three pre-configured scenes in OBS over the WebSocket connection — no manual Browser Source URLs, no JSON export/import. It's idempotent, so you can re-run it without clobbering scenes you've edited by hand.

  • AssemblyFlow Worship — Browser Source pre-pointed at the /obs endpoint at 1920×1080
  • AssemblyFlow Standby — empty scene; drop your camera source in
  • AssemblyFlow Blackout — empty scene for prayer or silence
OBS WebSocket control

Drive OBS without leaving AssemblyFlow.

AssemblyFlow connects to OBS via WebSocket — switch scenes, toggle stream / record, control the audio mixer, and show or hide sources from inside the booth window.

  • Per-item OBS scene override — song goes live, OBS switches to "Slides"; sermon starts, switches to "Camera"
  • Audio mixer panel — per-input volume, mute, monitor
  • Source visibility toggles in the current scene
  • Stream health in the toolbar — bitrate, dropped frames
Stream destination wizard

Set up YouTube, Facebook, Zoom, or RTMP in four steps.

A guided wizard walks first-time streamers through the platform-specific settings — server URL, stream key, bitrate, audio. Save multiple destinations per service.

  • Presets for YouTube Live, Facebook Live, Zoom Webinar, custom RTMP
  • Multi-destination per service (YouTube + Zoom + backup RTMP)
  • OBS scene-collection export — hand your AV volunteer an importable file
  • Printable setup-card PDF for the AV booth
NDI output

Broadcast-grade IP video over your LAN.

Subscribe from vMix, Wirecast, OBS-NDI, or any NDI-capable hardware switcher (Roland, Blackmagic). Zero-config — the switcher auto-discovers the AssemblyFlow NDI source on the network.

  • Slides plus alpha channel — composite freely on the switcher
  • Multiple subscribers OK — one source, many destinations
  • Sub-frame latency on a wired LAN
Virtual webcam

Appears in Zoom & Teams as a camera.

A Windows DirectShow virtual camera publishes your projection feed. Zoom, Teams, OBS, YouTube Studio, and Google Meet all see "AssemblyFlow Camera" in the camera-picker dropdown — no extra software, no cables.

  • Works with any app that accepts a webcam input
  • Same slides as the in-room audience, in real time
  • Great for shut-ins on a Zoom call or hybrid services
A mighty fortress is our God,
A bulwark never failing
— Tim Brown · Pulpit Minister
Projection

Borderless, fullscreen, no chrome.

What the congregation sees. A clean fullscreen window with hover-revealed controls and ~250 ms cross-fades between every slide. Three blank states: Standby with the AF or church logo, true blackout, and your custom logo screen.

  • Multi-monitor auto-detection — pick which display projection lands on
  • Themed backgrounds: solids, gradients, animated drift gradients, custom images or videos
  • Per-item background override for that one communion song
  • Church logo overlay — corner, configurable size + opacity
  • Lower thirds — animated speaker-name banners for preachers and guests
  • Closed-caption overlay — operator-typed or derived from the current slide
  • Pre-service countdown timer with quick presets (5 / 10 / 15 / 30 / 60 minutes)
  • Text effects: shadow, outline, custom fonts, per-item alignment
Stage display

What the worship team needs to see — and only them.

A second screen for the people on stage. Current slide in big text, UP NEXT preview, a live clock and elapsed-since-launch timer, and amber-bordered notes that never reach the congregation. For a cappella song leaders, the same window shows the pitch readout, hymnal page chips, key, tempo, and verse plan.

  • Large current-slide text, optimized for stage distance
  • UP NEXT preview so transitions don't surprise anyone
  • Live clock + elapsed timer in tabular numerals
  • Chord chart panel — visible only to the band, never the audience
  • Speaker notes & amber-bordered leader notes
SONG · 3 of 11
A Mighty Fortress
10:47:12
+18:04
Our helper He, amid the flood
Of mortal ills prevailing
UP NEXT Verse 4 — "That Word above all earthly pow'rs…"
NOTES Hold the half cadence at the end of v.2. Men only on bridge.
Web remote

Drive the screen from a phone — with roles and per-user links.

A built-in HTTP server binds to your church Wi-Fi. Any phone, tablet, or laptop on the same network opens a mobile-first page with Prev / Next / Blank and item-level jumps. For services with multiple operators, generate per-user links with role-based permissions.

  • Three roles: Operator (full control), Worship Leader (nav only — no blank/blackout), View-only (sees current slide)
  • Per-user access links with unique tokens — grant the song leader Worship Leader access without granting full control
  • Installable as a PWA — Android "Install app," iOS "Add to Home Screen" — gets the AF icon
  • Same command file as the booth — state stays in one place
  • Bound to LAN IP only — never leaves your network
AssemblyFlow ● LIVE
Role: Worship Leader · nav only
SONG · 3 of 16
A Mighty Fortress
Our helper He, amid the flood
Song Usage Analytics · Last 6 months
Amazing Grace 14×
How Great Thou Art 11×
A Mighty Fortress
Haven't sung in 6+ months
In Christ Alone · King of Kings · 12 more
52 services · 184 entries · 1 missing CCLI # Export CSV
CCLI tracking

Logs every song. Generates the report. Tells you what you haven't sung.

Every time a song projects, AssemblyFlow appends a log entry with timestamp, song title, your CCLI metadata, and your church's license number. When reporting season comes, export a CSV already in the right shape — and a usage-analytics dashboard surfaces patterns you can act on.

  • Per-song CCLI #, authors, copyright, publisher
  • Date-range reports (defaults to CCLI biannual)
  • Song usage analytics — most-sung, last-sung, songs not used in 6+ months
  • Practice mode — when rehearsing, AssemblyFlow doesn't log songs to CCLI (a visible banner reminds the operator)
  • Missing-data warnings catch blanks before submission
  • Edit metadata UI for filling in CCLI data as you go
  • All logs stored in data/ccli-usage/ — never sent anywhere
And the rest

Operator UX, accessibility, files & data.

The pieces that don't get marketed but matter every Sunday morning.

Lock / kiosk mode

Most editing controls grey out; only live-operation controls remain. Hand the booth to a volunteer without fear.

Live layout preset

Hide the song library, expand the preview pane, full focus on the live service. One click in the toolbar.

Pre-service walkthrough

Auto-cycles through every slide for a final QA pass before the doors open.

Keyboard shortcuts

next/prev slide · item · Space advance · B blank · . blackout

UI scale

Normal · Large · Extra Large. Roughly 30% bigger fonts and icons for older eyes or dim booths.

High contrast mode

Stronger text, darker outlines. For low-vision operators or service booths with bright Sunday sun.

Auto-advance

Configurable per item, 5–60 seconds, off by default. Useful for unattended pre-service announcement loops.

Undo / redo

Up to 20 service-plan states. Ctrl+Z / Ctrl+Y.

Recent services

Last 10 services, one click to reopen. Continuous autosave plus named saves ("Easter Sunday").

Backup to ZIP

One click bundles the entire data/ folder — services, custom songs, settings, license, web-remote users.

Restore from ZIP

Safety net: existing data is moved to data.before-restore-<timestamp> so a bad restore can be reversed.

Diagnostic export

Bundles logs, settings, and system info into one ZIP for support tickets — no scavenger hunt through Program Files.

Ready when you are.

Free for congregations of 50 or fewer. From $20/month for everyone else — Standard, Church, or Multi-campus.