Opportunities › AI API cost management for developers › Proposed app
Tollgate Keep
Spending caps, context alerts and model routing for teams building on AI APIs
- Score
- 62
- confidence 49
- Evidence
- 6
- items on the page
- Rivals
- 0
- named in sources
- First version
- 35 d
- estimate
- Type
- Desktop app
- PWA: runs in the browser, installs on Mac and Windows
- Market since
- 2023
- Emerging market · Verified
ScreensConcept
Desktop app: Developers configure budgets, review cost breakdowns, and analyze context growth in dashboards—seated work that benefits from a full screen and keyboard. Sample screens on a computer, in the proposed brand. Their numbers are sample data.
Budget
Over pace$212 / $300
About this appAI proposal
Tollgate Keep sits between your code and your AI model providers. You set a budget and an input size limit before you build, and it enforces both on every request. When a prompt starts to grow, it shows which part grew and when.
It is made for developers and small teams running language models in experiments or production, who today set rules by hand and read the bill afterwards.
Requests can be routed by rules you write: a cheaper model for short, simple calls, a stronger one for hard calls. Each rule shows its estimated saving before you switch it on. Unlike a log viewer, it acts before the money is spent: warn, trim, reroute or block.
- Tagline
- Set the limit first. Keep the bill predictable.
- Voice
- PlainCalmPrecise
- Why this name
- A tollgate is where you pay before passing; a keep is a safe place. Together: a checkpoint that guards your AI spend.
In the first version
Members say which features they would use. It tells PWAS what people want; it changes no score.
Budgets that stop spending
Set daily or monthly caps per project, key or teammate. At the limit, requests are blocked, rerouted to a cheaper model or let through with an alert.
No member yet
Input size limits
Set a maximum prompt size per endpoint. Oversized requests are rejected, trimmed or flagged before they reach the provider.
No member yet
Context creep tracker
Average prompt tokens per endpoint over time, split into system prompt, history and retrieved text, so you see what grew.
No member yet
Model routing rules
Route by size, tag or task. Preview estimated savings against your own recent traffic before enabling a rule.
No member yet
Brand identityAI proposal
Check the name against trademark registers before using it.
Palette
#0F4C4ADeep Teal · primary#F6F1E7Warm Paper · surface#1B2422Ink · text#E0A100Signal Amber · accent#B3402ABrick · alert#7FA99BSage · data
Typography
Aa
Tollgate Keep
PricingAI proposal
The material gives no competitor prices. These tiers are a starting point to test, not based on market data.
Free
Free
- 1 project
- Budget caps and alerts
- 7 days of history
Builder
$29 a month
- 5 projects
- Input size limits
- Routing rules with previews
- 90 days of history
Team
$99 a month
- Unlimited projects
- 10 seats
- Per-teammate budgets
- Webhooks and exports
Would you pay Builder · $29 a month?
Your answer tells PWAS which prices people accept. It changes no score.
No answers yet.
What it could be worthEstimate
What a software business making this much sells for today, from real deals. Pick a monthly revenue.
If it makes
Worth about
$194,000
Sale range $132,000 to $263,000
$120,000 a year in revenue
From 87 software businesses listed and sold on Empire Flippers in the last year, revenue vetted by the broker: they sell for about 19× their monthly revenue, most between 13× and 26×.
Measured on profit, the middle deal is 32× monthly net profit: about 2.7 years of profit.
An estimate, not an offer or financial advice. A real price depends on profit, growth, churn, how much of the work is the owner's, and the buyer.
How it would growAI proposal
How the product would reach new customers through its own use, and how the first ones would be found. A plan to test, not a result.
- Built-in loop
- No loop in the product. It runs behind customers' code, so users of their apps never see it. Reach comes from developer content, such as cost-saving write-ups, an open limits-config format and community posts.
- Do they become customers?
- Teammates who see the dashboard are already developers and could become paying seats. Test whether invited teammates upgrade the account, or whether one buyer decides alone.
- First customers
- Small teams of 2 to 10 developers running one LLM-based feature in production on a pay-per-token API, where one engineer owns the bill.
- Where to reach them
- Hacker News: Share a write-up on context creep with a free prompt-size checker, where developers already discuss overruns.
- Developer communities: Offer free setup help in AI engineering Discords and subreddits to teams that report a surprise bill.
- Direct outreach: Message founders and engineers who publicly post about LLM costs and offer a 30-minute audit.
- First milestone
- Ten teams route live traffic through the proxy for 30 days, and five pay for Builder or Team.
Why people already pay for this
- Public claimDevelopers experience significant unplanned cost overruns due to gradual expansion of prompts and requests without cost awareness.
- Public claimSetting input size limits upfront helps developers manage AI API costs more effectively.
- Public claimDevelopers are actively switching to lower-cost models when performance allows, indicating price sensitivity in AI API usage.
- Public claimLangfuse: more than 2,000 paying customers (Jan 2026)
- Public claimLangfuse: $4m seed round (Lightspeed, La Famiglia, Y Combinator) (Nov 2023)
Tech stack
Every proposal builds on the same PWA base, installable from the browser on any phone or computer. Dashed boxes are what this app adds.
- AppNext.js and TypeScript
- PWAManifest and service worker
- UITailwind CSS
- Data and authSupabase Postgres
- PaymentsStripe
- EmailResend
- HostingVercel
- This app · Proxy runtimeEdge functions for low-latency request forwardingEvery AI request passes through it, so it must add little delay and handle streaming responses.
- This app · Token countingProvider-compatible tokenizer librariesLimits and estimates need token counts before a request is sent.
RisksAI inference
- TechnicalA proxy in the request path adds latency and a failure point. Streaming, retries and provider outages must pass through without breaking customers' apps.
- CommercialLangfuse is cited with over 2,000 paying customers (public claim), so observability is served. Cost enforcement must prove it differs enough to win.
- PlatformProviders may add their own budgets and limits, and may change APIs and pricing, which would erode the value or break routing.
- DataHolding provider keys and prompt metadata is a security risk; a breach would end trust. Store only counts by default, not prompt text.
- AIAutomatic routing to cheaper models may lower answer quality unnoticed. Savings estimates cannot judge quality, so rules need opt-in and fallback.
Everything marked AI proposal or AI inference was written by a model from the evidence on the opportunity page. The proposed name must be checked against trademark registers before it is used.