Both apps let a tradesman send an invoice from his phone, capture a customer signature, and push the result into QuickBooks. That’s where the similarities end. Invoice ASAP has been around since 2009 and is built primarily for the solo end of field service. Billet is newer, launched in 2026, and is built for shops that send drivers out with trucks of inventory. Here’s the actual difference, by the numbers, with no marketing fluff.
Pricing
| App | Cheapest paid tier | What’s free | Top paid tier |
|---|---|---|---|
| Invoice ASAP | $3.99/mo Base | Free tier with unlimited invoices | $14.99/mo (QuickBooks or Xero edition) |
| Billet | $5/user/mo Essentials | 14-day trial, no credit card | $40/user/mo Professional |
Invoice ASAP’s pricing is per account. Billet’s is per active user. For a one-truck operation Invoice ASAP is cheaper. For a 4-driver shop the math flips. Invoice ASAP’s $14.99 is one fixed fee but locks you into one accounting integration and a smaller feature set, while Billet’s $5 × 4 = $20 unlocks the full Essentials tier including all four accounting integrations (QuickBooks Online, Xero, FreshBooks, Microsoft Dynamics 365).
What’s in the box
| Feature | Invoice ASAP | Billet |
|---|---|---|
| Mobile signature capture | Yes | Yes |
| Per-signature GPS proof | Used for routing; per-invoice not documented | Yes, stamped on every signed PDF |
| Photo capture per invoice | Yes, unlimited | 5 / 10 / unlimited by tier |
| Offline mode | Vendor says yes; users report frequent crashes when signal drops | Built for offline; signing and sync queue work with zero signal |
| Tap-to-pay credit card | 2.9% + $0.30 | Stripe Connect at Stripe’s standard rate, 0% Billet fee on top |
| ACH | 1% + $0.30 | Stripe Connect, 0.8% capped at $5 |
| QuickBooks Online | Two-way | Two-way |
| Xero | Direction not publicly documented | Two-way, with Quote import and tax-rate sync |
| FreshBooks | No integration | Two-way |
| Microsoft Dynamics 365 | No integration | Two-way |
| Public REST API + webhooks | Not advertised | All tiers |
| Zapier app | Not listed | 6 triggers, 3 actions, 2 searches (coming soon) |
| Route optimization | No | Standard tier, Google Routes API |
| Fleet GPS map | No | Standard tier, live driver positions |
| Counter / kiosk mode | No | Yes, $5 per device |
Where Invoice ASAP wins
The Free tier
If you’re sending five invoices a month and don’t need a fleet map, $0 beats $5. Invoice ASAP’s free tier handles unlimited invoices with signatures and photos. Billet’s free trial is 14 days, then $5 per active user per month. For someone running a one-person side business that’s a real difference.
Mature in solo field service
Sixteen years of plumbers and HVAC techs have shaped Invoice ASAP into something that fits the single-truck workflow naturally. The form fields, the recurring invoice setup, the deposit handling. It’s polished for that audience. Billet’s UX is built around someone leaving a warehouse with three deliveries in the truck, not someone diagnosing a leaky faucet.
Lower fixed processing fees on small ACH transactions
Invoice ASAP charges a flat 1% + $0.30 for ACH bank-to-bank payments. Billet routes through Stripe Connect at Stripe’s published rate (0.8% capped at $5). For a $50 invoice Invoice ASAP is slightly cheaper. For a $5,000 invoice Billet’s $5 cap saves real money. Different math depending on your average ticket size.
Where Billet wins
GPS proof on every signature
This is the biggest single difference. Billet captures the GPS coordinates of the device at the moment a customer signs, embeds them on the signed PDF, and syncs them back to QuickBooks. If a customer disputes the delivery, you have the timestamp, the GPS coordinates, and the customer’s signature on one document. Invoice ASAP uses GPS for travel-time reporting and route tracking, but per-invoice signature GPS is not a documented feature in the product.
For shops where a $4,000 boiler arrived at 8 in the morning and the customer is now telling their accountant nothing came, that single coordinate stamp is the proof that ends the dispute.
Offline mode that actually works
Read Invoice ASAP’s recent App Store and Capterra reviews and “the app crashes when it loses signal” is a top-five user complaint. Billet was built around the assumption that signal is going to drop. Warehouses with no cell service, customer driveways behind metal buildings, basements with one bar of LTE. Signing, photo capture, and the full sync queue all work fully offline. The queue processes the moment the device reconnects.
FreshBooks and Microsoft Dynamics integration
Invoice ASAP integrates with QuickBooks and Xero. Billet adds FreshBooks and Microsoft Dynamics 365 Business Central, both two-way. If you’re a Dynamics shop or a FreshBooks shop, Invoice ASAP isn’t on the table at all.
Counter Mode
A lot of distribution shops have a counter where walk-in customers pick up parts. Invoice ASAP doesn’t handle that workflow. Billet has a dedicated counter device mode: a tablet sits on the counter, the office assigns a ticket, the customer signs and optionally taps a card, done. Flat $5 per device per month on every tier.
Open API and webhooks on every tier
Invoice ASAP doesn’t advertise a public API. Billet ships a documented REST API on all three tiers and 15 webhook events with HMAC signing. A Zapier app with 6 triggers, 3 actions, and 2 searches is currently in Zapier marketplace review. If you ever want to build something custom on top of your invoicing, Billet has the surface to do it.
Per-active-user pricing scales fairly for teams
Invoice ASAP’s account-level $14.99 makes sense for solo. Billet’s per-active-user $5 makes sense for teams that want every driver, every office user, and every counter station on the same shared dispatch view. View-only office staff are free and don’t count toward the bill.
Which to pick
Pick Invoice ASAP if
- You’re a solo operator who needs an invoicing app on your phone
- You send fewer than 50 invoices a month
- $0 is the right price
- Your accounting software is QuickBooks or Xero only
- You don’t need GPS proof, route optimization, fleet visibility, or a counter
Pick Billet if
- You have a team (drivers, office staff, counter clerks)
- You deliver inventory rather than only service hours
- You want GPS embedded in every signature for proof of delivery
- You use FreshBooks or Microsoft Dynamics 365
- You expect to outgrow $14.99 within a year and don’t want to migrate later
The honest summary
Both are honest tools for honest work. Invoice ASAP is built for the one-truck plumber. Billet is built for the four-truck supply yard. Pick the one whose shape matches your shop, not the one that has the louder marketing.
If you’ve already got Invoice ASAP and the only thing you wish it had is signature-time GPS proof or proper offline mode or a counter device, Billet’s 14-day trial is the cheapest way to test whether the swap is worth it.
Try Billet free for 14 days
No credit card required. Connect QuickBooks, Xero, FreshBooks, or Microsoft Dynamics 365 during signup. Your first GPS-stamped signed invoice can go out this afternoon.